AES vs Blowfish for file encryption
Probably AES. Blowfish was the direct predecessor to Twofish. Twofish was Bruce Schneier's entry into the competition that produced AES. It was judged as inferior to an entry named Rijndael, which was what became AES.
Interesting aside: at one point in the competition, all the entrants were asked to give their opinion of how the ciphers ranked. It's probably no surprise that each team picked its own entry as the best -- but every other team picked Rijndael as the second best.
That said, there are some basic differences in the basic goals of Blowfish vs. AES that can (arguably) favor Blowfish in terms of absolute security. In particular, Blowfish attempts to make a brute-force (key-exhaustion) attack difficult by making the initial key setup a fairly slow operation. For a normal user, this is of little consequence (it's still less than a millisecond) but if you're trying out millions of keys per second to break it, the difference is quite substantial.
In the end, I don't see that as a major advantage, however. I'd generally recommend AES. My next choices would probably be Serpent, MARS and Twofish in that order. Blowfish would come somewhere after those (though there are a couple of others that I'd probably recommend ahead of Blowfish).
Encrypt and decrypt a string in C#?
I want to give you my contribute, with my code for AES Rfc2898DeriveBytes (here the documentation) algorhytm, written in C# (.NET framework 4) and fully working also for limited platforms, as .NET Compact Framework for Windows Phone 7.0+ (not all platforms support every criptographic method of the .NET framework!).
I hope this can help anyone!
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
public static class Crypto
{
private static readonly byte[] IVa = new byte[] { 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x11, 0x11, 0x12, 0x13, 0x14, 0x0e, 0x16, 0x17 };
public static string Encrypt(this string text, string salt)
{
try
{
using (Aes aes = new AesManaged())
{
Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(Encoding.UTF8.GetString(IVa, 0, IVa.Length), Encoding.UTF8.GetBytes(salt));
aes.Key = deriveBytes.GetBytes(128 / 8);
aes.IV = aes.Key;
using (MemoryStream encryptionStream = new MemoryStream())
{
using (CryptoStream encrypt = new CryptoStream(encryptionStream, aes.CreateEncryptor(), CryptoStreamMode.Write))
{
byte[] cleanText = Encoding.UTF8.GetBytes(text);
encrypt.Write(cleanText, 0, cleanText.Length);
encrypt.FlushFinalBlock();
}
byte[] encryptedData = encryptionStream.ToArray();
string encryptedText = Convert.ToBase64String(encryptedData);
return encryptedText;
}
}
}
catch
{
return String.Empty;
}
}
public static string Decrypt(this string text, string salt)
{
try
{
using (Aes aes = new AesManaged())
{
Rfc2898DeriveBytes deriveBytes = new Rfc2898DeriveBytes(Encoding.UTF8.GetString(IVa, 0, IVa.Length), Encoding.UTF8.GetBytes(salt));
aes.Key = deriveBytes.GetBytes(128 / 8);
aes.IV = aes.Key;
using (MemoryStream decryptionStream = new MemoryStream())
{
using (CryptoStream decrypt = new CryptoStream(decryptionStream, aes.CreateDecryptor(), CryptoStreamMode.Write))
{
byte[] encryptedData = Convert.FromBase64String(text);
decrypt.Write(encryptedData, 0, encryptedData.Length);
decrypt.Flush();
}
byte[] decryptedData = decryptionStream.ToArray();
string decryptedText = Encoding.UTF8.GetString(decryptedData, 0, decryptedData.Length);
return decryptedText;
}
}
}
catch
{
return String.Empty;
}
}
}
}
java.io.IOException: Invalid Keystore format
go to build clean the project then rebuild your project it worked for me.
javax.crypto.IllegalBlockSizeException : Input length must be multiple of 16 when decrypting with padded cipher
The algorithm you are using, "AES", is a shorthand for "AES/ECB/NoPadding". What this means is that you are using the AES algorithm with 128-bit key size and block size, with the ECB mode of operation and no padding.
In other words: you are only able to encrypt data in blocks of 128 bits or 16 bytes. That's why you are getting that IllegalBlockSizeException exception.
If you want to encrypt data in sizes that are not multiple of 16 bytes, you are either going to have to use some kind of padding, or a cipher-stream. For instance, you could use CBC mode (a mode of operation that effectively transforms a block cipher into a stream cipher) by specifying "AES/CBC/NoPadding" as the algorithm, or PKCS5 padding by specifying "AES/ECB/PKCS5", which will automatically add some bytes at the end of your data in a very specific format to make the size of the ciphertext multiple of 16 bytes, and in a way that the decryption algorithm will understand that it has to ignore some data.
In any case, I strongly suggest that you stop right now what you are doing and go study some very introductory material on cryptography. For instance, check Crypto I on Coursera. You should understand very well the implications of choosing one mode or another, what are their strengths and, most importantly, their weaknesses. Without this knowledge, it is very easy to build systems which are very easy to break.
Update: based on your comments on the question, don't ever encrypt passwords when storing them at a database!!!!! You should never, ever do this. You must HASH the passwords, properly salted, which is completely different from encrypting. Really, please, don't do what you are trying to do... By encrypting the passwords, they can be decrypted. What this means is that you, as the database manager and who knows the secret key, you will be able to read every password stored in your database. Either you knew this and are doing something very, very bad, or you didn't know this, and should get shocked and stop it.
mcrypt is deprecated, what is the alternative?
You can use phpseclib pollyfill package. You can not use open ssl or libsodium for encrypt/decrypt with rijndael 256. Another issue, you don't need replacement any code.
How to fix Invalid AES key length?
Things to know in general:
- Key != Password
SecretKeySpecexpects a key, not a password. See below
- It might be due to a policy restriction that prevents using 32 byte keys. See other answer on that
In your case
The problem is number 1: you are passing the password instead of the key.
AES only supports key sizes of 16, 24 or 32 bytes. You either need to provide exactly that amount or you derive the key from what you type in.
There are different ways to derive the key from a passphrase. Java provides a PBKDF2 implementation for such a purpose.
I used erickson's answer to paint a complete picture (only encryption, since the decryption is similar, but includes splitting the ciphertext):
SecureRandom random = new SecureRandom();
byte[] salt = new byte[16];
random.nextBytes(salt);
KeySpec spec = new PBEKeySpec("password".toCharArray(), salt, 65536, 256); // AES-256
SecretKeyFactory f = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
byte[] key = f.generateSecret(spec).getEncoded();
SecretKeySpec keySpec = new SecretKeySpec(key, "AES");
byte[] ivBytes = new byte[16];
random.nextBytes(ivBytes);
IvParameterSpec iv = new IvParameterSpec(ivBytes);
Cipher c = Cipher.getInstance("AES/CBC/PKCS5Padding");
c.init(Cipher.ENCRYPT_MODE, keySpec, iv);
byte[] encValue = c.doFinal(valueToEnc.getBytes());
byte[] finalCiphertext = new byte[encValue.length+2*16];
System.arraycopy(ivBytes, 0, finalCiphertext, 0, 16);
System.arraycopy(salt, 0, finalCiphertext, 16, 16);
System.arraycopy(encValue, 0, finalCiphertext, 32, encValue.length);
return finalCiphertext;
Other things to keep in mind:
- Always use a fully qualified Cipher name.
AESis not appropriate in such a case, because different JVMs/JCE providers may use different defaults for mode of operation and padding. UseAES/CBC/PKCS5Padding. Don't use ECB mode, because it is not semantically secure. - If you don't use ECB mode then you need to send the IV along with the ciphertext. This is usually done by prefixing the IV to the ciphertext byte array. The IV is automatically created for you and you can get it through
cipherInstance.getIV(). - Whenever you send something, you need to be sure that it wasn't altered along the way. It is hard to implement a encryption with MAC correctly. I recommend you to use an authenticated mode like CCM or GCM.
InvalidKeyException : Illegal Key Size - Java code throwing exception for encryption class - how to fix?
Add below code in your client code :
static {
Security.insertProviderAt(new BouncyCastleProvider(),1);
}
with this there is no need to add any entry in java.security file.
How to send password securely over HTTP?
You can use SRP to use secure passwords over an insecure channel. The advantage is that even if an attacker sniffs the traffic, or compromises the server, they can't use the passwords on a different server. https://github.com/alax/jsrp is a javascript library that supports secure passwords over HTTP in the browser, or server side (via node).
What's the difference between SHA and AES encryption?
SHA isn't encryption, it's a one-way hash function. AES (Advanced_Encryption_Standard) is a symmetric encryption standard.
How do I encrypt and decrypt a string in python?
Take a look at PyCrypto. It supports Python 3.2 and does exactly what you want.
From their pip website:
>>> from Crypto.Cipher import AES
>>> obj = AES.new('This is a key123', AES.MODE_CFB, 'This is an IV456')
>>> message = "The answer is no"
>>> ciphertext = obj.encrypt(message)
>>> ciphertext
'\xd6\x83\x8dd!VT\x92\xaa`A\x05\xe0\x9b\x8b\xf1'
>>> obj2 = AES.new('This is a key123', AES.MODE_CFB, 'This is an IV456')
>>> obj2.decrypt(ciphertext)
'The answer is no'
If you want to encrypt a message of an arbitrary size use AES.MODE_CFB instead of AES.MODE_CBC.
How to use OpenSSL to encrypt/decrypt files?
Update using a random generated public key.
Encypt:
openssl enc -aes-256-cbc -a -salt -in {raw data} -out {encrypted data} -pass file:{random key}
Decrypt:
openssl enc -d -aes-256-cbc -in {ciphered data} -out {raw data}
C# Example of AES256 encryption using System.Security.Cryptography.Aes
Maybe this example listed here can help you out. Statement from the author
about 24 lines of code to encrypt, 23 to decrypt
Due to the fact that the link in the original posting is dead - here the needed code parts (c&p without any change to the original source)
/*
Copyright (c) 2010 <a href="http://www.gutgames.com">James Craig</a>
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.*/
#region Usings
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
#endregion
namespace Utilities.Encryption
{
/// <summary>
/// Utility class that handles encryption
/// </summary>
public static class AESEncryption
{
#region Static Functions
/// <summary>
/// Encrypts a string
/// </summary>
/// <param name="PlainText">Text to be encrypted</param>
/// <param name="Password">Password to encrypt with</param>
/// <param name="Salt">Salt to encrypt with</param>
/// <param name="HashAlgorithm">Can be either SHA1 or MD5</param>
/// <param name="PasswordIterations">Number of iterations to do</param>
/// <param name="InitialVector">Needs to be 16 ASCII characters long</param>
/// <param name="KeySize">Can be 128, 192, or 256</param>
/// <returns>An encrypted string</returns>
public static string Encrypt(string PlainText, string Password,
string Salt = "Kosher", string HashAlgorithm = "SHA1",
int PasswordIterations = 2, string InitialVector = "OFRna73m*aze01xY",
int KeySize = 256)
{
if (string.IsNullOrEmpty(PlainText))
return "";
byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
byte[] PlainTextBytes = Encoding.UTF8.GetBytes(PlainText);
PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.Mode = CipherMode.CBC;
byte[] CipherTextBytes = null;
using (ICryptoTransform Encryptor = SymmetricKey.CreateEncryptor(KeyBytes, InitialVectorBytes))
{
using (MemoryStream MemStream = new MemoryStream())
{
using (CryptoStream CryptoStream = new CryptoStream(MemStream, Encryptor, CryptoStreamMode.Write))
{
CryptoStream.Write(PlainTextBytes, 0, PlainTextBytes.Length);
CryptoStream.FlushFinalBlock();
CipherTextBytes = MemStream.ToArray();
MemStream.Close();
CryptoStream.Close();
}
}
}
SymmetricKey.Clear();
return Convert.ToBase64String(CipherTextBytes);
}
/// <summary>
/// Decrypts a string
/// </summary>
/// <param name="CipherText">Text to be decrypted</param>
/// <param name="Password">Password to decrypt with</param>
/// <param name="Salt">Salt to decrypt with</param>
/// <param name="HashAlgorithm">Can be either SHA1 or MD5</param>
/// <param name="PasswordIterations">Number of iterations to do</param>
/// <param name="InitialVector">Needs to be 16 ASCII characters long</param>
/// <param name="KeySize">Can be 128, 192, or 256</param>
/// <returns>A decrypted string</returns>
public static string Decrypt(string CipherText, string Password,
string Salt = "Kosher", string HashAlgorithm = "SHA1",
int PasswordIterations = 2, string InitialVector = "OFRna73m*aze01xY",
int KeySize = 256)
{
if (string.IsNullOrEmpty(CipherText))
return "";
byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
byte[] CipherTextBytes = Convert.FromBase64String(CipherText);
PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
RijndaelManaged SymmetricKey = new RijndaelManaged();
SymmetricKey.Mode = CipherMode.CBC;
byte[] PlainTextBytes = new byte[CipherTextBytes.Length];
int ByteCount = 0;
using (ICryptoTransform Decryptor = SymmetricKey.CreateDecryptor(KeyBytes, InitialVectorBytes))
{
using (MemoryStream MemStream = new MemoryStream(CipherTextBytes))
{
using (CryptoStream CryptoStream = new CryptoStream(MemStream, Decryptor, CryptoStreamMode.Read))
{
ByteCount = CryptoStream.Read(PlainTextBytes, 0, PlainTextBytes.Length);
MemStream.Close();
CryptoStream.Close();
}
}
}
SymmetricKey.Clear();
return Encoding.UTF8.GetString(PlainTextBytes, 0, ByteCount);
}
#endregion
}
}
AES Encrypt and Decrypt
Update Swift 4.2
Here, for instance, we encrypt a string to base64encoded string. And then we decrypt the same to a readable string. (That would be same as our input string).
In my case, I use this to encrypt a string and embed that to QR Code. Then another party scan that and decrypt the same. So intermediate won't understand the QR codes.
Step 1: Encrypt a string "Encrypt My Message 123"
Step 2: Encrypted base64Encoded string : +yvNjiD7F9/JKmqHTc/Mjg== (The same printed on QR code)
Step 3: Scan and decrypt the string "+yvNjiD7F9/JKmqHTc/Mjg=="
Step 4: It comes final result - "Encrypt My Message 123"
Functions for Encrypt & Decrypt
func encryption(stringToEncrypt: String) -> String{
let key = "MySecretPKey"
//let iv = "92c9d2c07a9f2e0a"
let data = stringToEncrypt.data(using: .utf8)
let keyD = key.data(using: .utf8)
let encr = (data as NSData?)!.aes128EncryptedData(withKey: keyD)
let base64String: String = (encr as NSData?)!.base64EncodedString(options: NSData.Base64EncodingOptions(rawValue: 0))
print(base64String)
return base64String
}
func decryption(encryptedString:String) -> String{
let key = "MySecretPKey"
//let iv = "92c9d2c07a9f2e0a"
let keyD = key.data(using: .utf8)
let decrpStr = NSData(base64Encoded: encryptedString, options: NSData.Base64DecodingOptions(rawValue: 0))
let dec = (decrpStr)!.aes128DecryptedData(withKey: keyD)
let backToString = String(data: dec!, encoding: String.Encoding.utf8)
print(backToString!)
return backToString!
}
Usage:
let enc = encryption(stringToEncrypt: "Encrypt My Message 123")
let decryptedString = decryption(encryptedString: enc)
print(decryptedString)
Classes for supporting AES encrypting functions, these are written in Objective-C. So for swift, you need to use bridge header to support these.
Class Name: NSData+AES.h
#import <Foundation/Foundation.h>
@interface NSData (AES)
- (NSData *)AES128EncryptedDataWithKey:(NSData *)key;
- (NSData *)AES128DecryptedDataWithKey:(NSData *)key;
- (NSData *)AES128EncryptedDataWithKey:(NSData *)key iv:(NSData *)iv;
- (NSData *)AES128DecryptedDataWithKey:(NSData *)key iv:(NSData *)iv;
@end
Class Name: NSData+AES.m
#import "NSData+AES.h"
#import <CommonCrypto/CommonCryptor.h>
@implementation NSData (AES)
- (NSData *)AES128EncryptedDataWithKey:(NSData *)key
{
return [self AES128EncryptedDataWithKey:key iv:nil];
}
- (NSData *)AES128DecryptedDataWithKey:(NSData *)key
{
return [self AES128DecryptedDataWithKey:key iv:nil];
}
- (NSData *)AES128EncryptedDataWithKey:(NSData *)key iv:(NSData *)iv
{
return [self AES128Operation:kCCEncrypt key:key iv:iv];
}
- (NSData *)AES128DecryptedDataWithKey:(NSData *)key iv:(NSData *)iv
{
return [self AES128Operation:kCCDecrypt key:key iv:iv];
}
- (NSData *)AES128Operation:(CCOperation)operation key:(NSData *)key iv:(NSData *)iv
{
NSUInteger dataLength = [self length];
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);
size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(operation,
kCCAlgorithmAES128,
kCCOptionPKCS7Padding | kCCOptionECBMode,
key.bytes,
kCCBlockSizeAES128,
iv.bytes,
[self bytes],
dataLength,
buffer,
bufferSize,
&numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}
free(buffer);
return nil;
}
@end
I hope that helps.
Thanks!!!
Given final block not properly padded
This can also be a issue when you enter wrong password for your sign key.
Image encryption/decryption using AES256 symmetric block ciphers
Warning: This answer contains code you should not use as it is insecure (using SHA1PRNG for key derivation and using AES in ECB mode)
Instead (as of 2016), use PBKDF2WithHmacSHA1 for key derivation and AES in CBC or GCM mode (GCM provides both privacy and integrity)
You could use functions like these:
private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(clear);
return encrypted;
}
private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decrypted = cipher.doFinal(encrypted);
return decrypted;
}
And invoke them like this:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bm.compress(Bitmap.CompressFormat.PNG, 100, baos); // bm is the bitmap object
byte[] b = baos.toByteArray();
byte[] keyStart = "this is a key".getBytes();
KeyGenerator kgen = KeyGenerator.getInstance("AES");
SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");
sr.setSeed(keyStart);
kgen.init(128, sr); // 192 and 256 bits may not be available
SecretKey skey = kgen.generateKey();
byte[] key = skey.getEncoded();
// encrypt
byte[] encryptedData = encrypt(key,b);
// decrypt
byte[] decryptedData = decrypt(key,encryptedData);
This should work, I use similar code in a project right now.
RSA encryption and decryption in Python
You can use simple way for genarate RSA . Use rsa library
pip install rsa
Does my application "contain encryption"?
If you're not explicitly using an encryption library, or rolling your own encryption code, then I think the answer is "no"
Java 256-bit AES Password-Based Encryption
Adding to @Wufoo's edits, the following version uses InputStreams rather than files to make working with a variety of files easier. It also stores the IV and Salt in the beginning of the file, making it so only the password needs to be tracked. Since the IV and Salt do not need to be secret, this makes life a little easier.
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.AlgorithmParameters;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.InvalidParameterSpecException;
import java.security.spec.KeySpec;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
public class AES {
public final static int SALT_LEN = 8;
static final String HEXES = "0123456789ABCDEF";
String mPassword = null;
byte[] mInitVec = null;
byte[] mSalt = new byte[SALT_LEN];
Cipher mEcipher = null;
Cipher mDecipher = null;
private final int KEYLEN_BITS = 128; // see notes below where this is used.
private final int ITERATIONS = 65536;
private final int MAX_FILE_BUF = 1024;
/**
* create an object with just the passphrase from the user. Don't do anything else yet
* @param password
*/
public AES(String password) {
mPassword = password;
}
public static String byteToHex(byte[] raw) {
if (raw == null) {
return null;
}
final StringBuilder hex = new StringBuilder(2 * raw.length);
for (final byte b : raw) {
hex.append(HEXES.charAt((b & 0xF0) >> 4)).append(HEXES.charAt((b & 0x0F)));
}
return hex.toString();
}
public static byte[] hexToByte(String hexString) {
int len = hexString.length();
byte[] ba = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
ba[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4)
+ Character.digit(hexString.charAt(i + 1), 16));
}
return ba;
}
/**
* debug/print messages
* @param msg
*/
private void Db(String msg) {
System.out.println("** Crypt ** " + msg);
}
/**
* This is where we write out the actual encrypted data to disk using the Cipher created in setupEncrypt().
* Pass two file objects representing the actual input (cleartext) and output file to be encrypted.
*
* there may be a way to write a cleartext header to the encrypted file containing the salt, but I ran
* into uncertain problems with that.
*
* @param input - the cleartext file to be encrypted
* @param output - the encrypted data file
* @throws IOException
* @throws IllegalBlockSizeException
* @throws BadPaddingException
*/
public void WriteEncryptedFile(InputStream inputStream, OutputStream outputStream)
throws IOException, IllegalBlockSizeException, BadPaddingException {
try {
long totalread = 0;
int nread = 0;
byte[] inbuf = new byte[MAX_FILE_BUF];
SecretKeyFactory factory = null;
SecretKey tmp = null;
// crate secureRandom salt and store as member var for later use
mSalt = new byte[SALT_LEN];
SecureRandom rnd = new SecureRandom();
rnd.nextBytes(mSalt);
Db("generated salt :" + byteToHex(mSalt));
factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
/*
* Derive the key, given password and salt.
*
* in order to do 256 bit crypto, you have to muck with the files for Java's "unlimted security"
* The end user must also install them (not compiled in) so beware.
* see here: http://www.javamex.com/tutorials/cryptography/unrestricted_policy_files.shtml
*/
KeySpec spec = new PBEKeySpec(mPassword.toCharArray(), mSalt, ITERATIONS, KEYLEN_BITS);
tmp = factory.generateSecret(spec);
SecretKey secret = new SecretKeySpec(tmp.getEncoded(), "AES");
/*
* Create the Encryption cipher object and store as a member variable
*/
mEcipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
mEcipher.init(Cipher.ENCRYPT_MODE, secret);
AlgorithmParameters params = mEcipher.getParameters();
// get the initialization vectory and store as member var
mInitVec = params.getParameterSpec(IvParameterSpec.class).getIV();
Db("mInitVec is :" + byteToHex(mInitVec));
outputStream.write(mSalt);
outputStream.write(mInitVec);
while ((nread = inputStream.read(inbuf)) > 0) {
Db("read " + nread + " bytes");
totalread += nread;
// create a buffer to write with the exact number of bytes read. Otherwise a short read fills inbuf with 0x0
// and results in full blocks of MAX_FILE_BUF being written.
byte[] trimbuf = new byte[nread];
for (int i = 0; i < nread; i++) {
trimbuf[i] = inbuf[i];
}
// encrypt the buffer using the cipher obtained previosly
byte[] tmpBuf = mEcipher.update(trimbuf);
// I don't think this should happen, but just in case..
if (tmpBuf != null) {
outputStream.write(tmpBuf);
}
}
// finalize the encryption since we've done it in blocks of MAX_FILE_BUF
byte[] finalbuf = mEcipher.doFinal();
if (finalbuf != null) {
outputStream.write(finalbuf);
}
outputStream.flush();
inputStream.close();
outputStream.close();
outputStream.close();
Db("wrote " + totalread + " encrypted bytes");
} catch (InvalidKeyException ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidParameterSpecException ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
} catch (NoSuchPaddingException ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
} catch (InvalidKeySpecException ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Read from the encrypted file (input) and turn the cipher back into cleartext. Write the cleartext buffer back out
* to disk as (output) File.
*
* I left CipherInputStream in here as a test to see if I could mix it with the update() and final() methods of encrypting
* and still have a correctly decrypted file in the end. Seems to work so left it in.
*
* @param input - File object representing encrypted data on disk
* @param output - File object of cleartext data to write out after decrypting
* @throws IllegalBlockSizeException
* @throws BadPaddingException
* @throws IOException
*/
public void ReadEncryptedFile(InputStream inputStream, OutputStream outputStream)
throws IllegalBlockSizeException, BadPaddingException, IOException {
try {
CipherInputStream cin;
long totalread = 0;
int nread = 0;
byte[] inbuf = new byte[MAX_FILE_BUF];
// Read the Salt
inputStream.read(this.mSalt);
Db("generated salt :" + byteToHex(mSalt));
SecretKeyFactory factory = null;
SecretKey tmp = null;
SecretKey secret = null;
factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec spec = new PBEKeySpec(mPassword.toCharArray(), mSalt, ITERATIONS, KEYLEN_BITS);
tmp = factory.generateSecret(spec);
secret = new SecretKeySpec(tmp.getEncoded(), "AES");
/* Decrypt the message, given derived key and initialization vector. */
mDecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
// Set the appropriate size for mInitVec by Generating a New One
AlgorithmParameters params = mDecipher.getParameters();
mInitVec = params.getParameterSpec(IvParameterSpec.class).getIV();
// Read the old IV from the file to mInitVec now that size is set.
inputStream.read(this.mInitVec);
Db("mInitVec is :" + byteToHex(mInitVec));
mDecipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(mInitVec));
// creating a decoding stream from the FileInputStream above using the cipher created from setupDecrypt()
cin = new CipherInputStream(inputStream, mDecipher);
while ((nread = cin.read(inbuf)) > 0) {
Db("read " + nread + " bytes");
totalread += nread;
// create a buffer to write with the exact number of bytes read. Otherwise a short read fills inbuf with 0x0
byte[] trimbuf = new byte[nread];
for (int i = 0; i < nread; i++) {
trimbuf[i] = inbuf[i];
}
// write out the size-adjusted buffer
outputStream.write(trimbuf);
}
outputStream.flush();
cin.close();
inputStream.close();
outputStream.close();
Db("wrote " + totalread + " encrypted bytes");
} catch (Exception ex) {
Logger.getLogger(AES.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* adding main() for usage demonstration. With member vars, some of the locals would not be needed
*/
public static void main(String[] args) {
// create the input.txt file in the current directory before continuing
File input = new File("input.txt");
File eoutput = new File("encrypted.aes");
File doutput = new File("decrypted.txt");
String iv = null;
String salt = null;
AES en = new AES("mypassword");
/*
* write out encrypted file
*/
try {
en.WriteEncryptedFile(new FileInputStream(input), new FileOutputStream(eoutput));
System.out.printf("File encrypted to " + eoutput.getName() + "\niv:" + iv + "\nsalt:" + salt + "\n\n");
} catch (IllegalBlockSizeException | BadPaddingException | IOException e) {
e.printStackTrace();
}
/*
* decrypt file
*/
AES dc = new AES("mypassword");
/*
* write out decrypted file
*/
try {
dc.ReadEncryptedFile(new FileInputStream(eoutput), new FileOutputStream(doutput));
System.out.println("decryption finished to " + doutput.getName());
} catch (IllegalBlockSizeException | BadPaddingException | IOException e) {
e.printStackTrace();
}
}
}
How do you Encrypt and Decrypt a PHP String?
Below code work in php for all string with special character
// Encrypt text --
$token = "9611222007552";
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$enc_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($cipher_method));
$crypted_token = openssl_encrypt($token, $cipher_method, $enc_key, 0, $enc_iv) . "::" . bin2hex($enc_iv);
echo $crypted_token;
//unset($token, $cipher_method, $enc_key, $enc_iv);
// Decrypt text --
list($crypted_token, $enc_iv) = explode("::", $crypted_token);
$cipher_method = 'aes-128-ctr';
$enc_key = openssl_digest(php_uname(), 'SHA256', TRUE);
$token = openssl_decrypt($crypted_token, $cipher_method, $enc_key, 0, hex2bin($enc_iv));
echo $token;
//unset($crypted_token, $cipher_method, $enc_key, $enc_iv);
Converting Secret Key into a String and Vice Versa
Converting SecretKeySpec to String and vice-versa:
you can use getEncoded() method in SecretKeySpec which will give byteArray, from that you can use encodeToString() to get string value of SecretKeySpec in Base64 object.
While converting SecretKeySpec to String: use decode() in Base64 will give byteArray, from that you can create instance for SecretKeySpec with the params as the byteArray to reproduce your SecretKeySpec.
String mAesKey_string;
SecretKeySpec mAesKey= new SecretKeySpec(secretKey.getEncoded(), "AES");
//SecretKeySpec to String
byte[] byteaes=mAesKey.getEncoded();
mAesKey_string=Base64.encodeToString(byteaes,Base64.NO_WRAP);
//String to SecretKeySpec
byte[] aesByte = Base64.decode(mAesKey_string, Base64.NO_WRAP);
mAesKey= new SecretKeySpec(aesByte, "AES");
What is the most appropriate way to store user settings in Android application
About the simplest way to store a single preference in an Android Activity is to do something like this:
Editor e = this.getPreferences(Context.MODE_PRIVATE).edit();
e.putString("password", mPassword);
e.commit();
If you're worried about the security of these then you could always encrypt the password before storing it.
Converting a Java Keystore into PEM Format
Converting a Java Keystore into PEM Format
The most precise answer of all must be that this is NOT possible.
A Java keystore is merely a storage facility for cryptographic keys and certificates while PEM is a file format for X.509 certificates only.
Encrypting & Decrypting a String in C#
using System.IO;
using System.Text;
using System.Security.Cryptography;
public static class EncryptionHelper
{
public static string Encrypt(string clearText)
{
string EncryptionKey = "abc123";
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
encryptor.Key = pdb.GetBytes(32);
encryptor.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(clearBytes, 0, clearBytes.Length);
cs.Close();
}
clearText = Convert.ToBase64String(ms.ToArray());
}
}
return clearText;
}
public static string Decrypt(string cipherText)
{
string EncryptionKey = "abc123";
cipherText = cipherText.Replace(" ", "+");
byte[] cipherBytes = Convert.FromBase64String(cipherText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
encryptor.Key = pdb.GetBytes(32);
encryptor.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(cipherBytes, 0, cipherBytes.Length);
cs.Close();
}
cipherText = Encoding.Unicode.GetString(ms.ToArray());
}
}
return cipherText;
}
}
Password encryption/decryption code in .NET
string clearText = txtPassword.Text;
string EncryptionKey = "MAKV2SPBNI99212";
byte[] clearBytes = Encoding.Unicode.GetBytes(clearText);
using (Aes encryptor = Aes.Create())
{
Rfc2898DeriveBytes pdb = new Rfc2898DeriveBytes(EncryptionKey, new byte[] { 0x49, 0x76, 0x61, 0x6e, 0x20, 0x4d, 0x65, 0x64, 0x76, 0x65, 0x64, 0x65, 0x76 });
encryptor.Key = pdb.GetBytes(32);
encryptor.IV = pdb.GetBytes(16);
using (MemoryStream ms = new MemoryStream())
{
using (CryptoStream cs = new CryptoStream(ms, encryptor.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(clearBytes, 0, clearBytes.Length);
cs.Close();
}
clearText = Convert.ToBase64String(ms.ToArray());
}
}
SHA512 vs. Blowfish and Bcrypt
Blowfish is not a hashing algorithm. It's an encryption algorithm. What that means is that you can encrypt something using blowfish, and then later on you can decrypt it back to plain text.
SHA512 is a hashing algorithm. That means that (in theory) once you hash the input you can't get the original input back again.
They're 2 different things, designed to be used for different tasks. There is no 'correct' answer to "is blowfish better than SHA512?" You might as well ask "are apples better than kangaroos?"
If you want to read some more on the topic here's some links:
JavaScript string encryption and decryption?
Before implementying any of this, please see Scott Arciszewski's answer.
I want you to be very careful with what I'm about to share as I have little to no security knowledge (There's a high chance that I'm misusing the API below), so I'd be more than welcome to update this answer with the help of the community.
As @richardtallent mentioned in his answer, there's support for the Web Crypto API, so this example uses the standard. As of this writing, there's a 95.88% of global browser support.
I'm going to be sharing an example using the Web Crypto API
Before we proceed, please note (Quoting from MDN):
This API provides a number of low-level cryptographic primitives. It's very easy to misuse them, and the pitfalls involved can be very subtle.
Even assuming you use the basic cryptographic functions correctly, secure key management and overall security system design are extremely hard to get right and are generally the domain of specialist security experts.
Errors in security system design and implementation can make the security of the system completely ineffective.
If you're not sure you know what you are doing, you probably shouldn't be using this API.
I respect security a lot, and I even bolded additional parts from MDN... You've been warned
Now, to the actual example...
JSFiddle:
Found here: https://jsfiddle.net/superjose/rm4e0gqa/5/
Note:
Note the use of await keywords. Use it inside an async function or use .then() and .catch().
Generate the key:
// https://developer.mozilla.org/en-US/docs/Web/API/CryptoKey
// https://developer.mozilla.org/en-US/docs/Web/API/RsaHashedKeyGenParams
// https://github.com/diafygi/webcrypto-examples#rsa-oaep---generatekey
const stringToEncrypt = 'https://localhost:3001';
// https://github.com/diafygi/webcrypto-examples#rsa-oaep---generatekey
// The resultant publicKey will be used to encrypt
// and the privateKey will be used to decrypt.
// Note: This will generate new keys each time, you must store both of them in order for
// you to keep encrypting and decrypting.
//
// I warn you that storing them in the localStorage may be a bad idea, and it gets out of the scope
// of this post.
const key = await crypto.subtle.generateKey({
name: 'RSA-OAEP',
modulusLength: 4096,
publicExponent: new Uint8Array([0x01, 0x00, 0x01]),
hash: {name: 'SHA-512'},
}, true,
// This depends a lot on the algorithm used
// Go to https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto
// and scroll down to see the table. Since we're using RSA-OAEP we have encrypt and decrypt available
['encrypt', 'decrypt']);
// key will yield a key.publicKey and key.privateKey property.
Encrypt:
const encryptedUri = await crypto.subtle.encrypt({
name: 'RSA-OAEP'
}, key.publicKey, stringToArrayBuffer(stringToEncrypt))
console.log('The encrypted string is', encryptedUri);
Decrypt
const msg = await crypto.subtle.decrypt({
name: 'RSA-OAEP',
}, key.privateKey, encryptedUri);
console.log(`Derypted Uri is ${arrayBufferToString(msg)}`)
Converting ArrayBuffer back and forth from String (Done in TypeScript):
private arrayBufferToString(buff: ArrayBuffer) {
return String.fromCharCode.apply(null, new Uint16Array(buff) as unknown as number[]);
}
private stringToArrayBuffer(str: string) {
const buff = new ArrayBuffer(str.length*2) // Because there are 2 bytes for each char.
const buffView = new Uint16Array(buff);
for(let i = 0, strLen = str.length; i < strLen; i++) {
buffView[i] = str.charCodeAt(i);
}
return buff;
}
You can find more examples here (I'm not the owner): // https://github.com/diafygi/webcrypto-examples
How to export non-exportable private key from store
This worked for me on Windows Server 2012 - I needed to export a non-exportable certificate to setup another ADFS server and this did the trick. Remember to use the jailbreak instructions above i.e.:
crypto::certificates /export /systemstore:CERT_SYSTEM_STORE_LOCAL_MACHINE
Java, How to implement a Shift Cipher (Caesar Cipher)
Below code handles upper and lower cases as well and leaves other character as it is.
import java.util.Scanner;
public class CaesarCipher
{
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int length = Integer.parseInt(in.nextLine());
String str = in.nextLine();
int k = Integer.parseInt(in.nextLine());
k = k % 26;
System.out.println(encrypt(str, length, k));
in.close();
}
private static String encrypt(String str, int length, int shift)
{
StringBuilder strBuilder = new StringBuilder();
char c;
for (int i = 0; i < length; i++)
{
c = str.charAt(i);
// if c is letter ONLY then shift them, else directly add it
if (Character.isLetter(c))
{
c = (char) (str.charAt(i) + shift);
// System.out.println(c);
// checking case or range check is important, just if (c > 'z'
// || c > 'Z')
// will not work
if ((Character.isLowerCase(str.charAt(i)) && c > 'z')
|| (Character.isUpperCase(str.charAt(i)) && c > 'Z'))
c = (char) (str.charAt(i) - (26 - shift));
}
strBuilder.append(c);
}
return strBuilder.toString();
}
}
What is the difference between DSA and RSA?
With reference to man ssh-keygen, the length of a DSA key is restricted to exactly 1024 bit to remain compliant with NIST's FIPS 186-2. Nonetheless, longer DSA keys are theoretically possible; FIPS 186-3 explicitly allows them. Furthermore, security is no longer guaranteed with 1024 bit long RSA or DSA keys.
In conclusion, a 2048 bit RSA key is currently the best choice.
MORE PRECAUTIONS TO TAKE
Establishing a secure SSH connection entails more than selecting safe encryption key pair technology. In view of Edward Snowden's NSA revelations, one has to be even more vigilant than what previously was deemed sufficient.
To name just one example, using a safe key exchange algorithm is equally important. Here is a nice overview of current best SSH hardening practices.
How does BitLocker affect performance?
I am talking here from a theoretical point of view; I have not tried BitLocker.
BitLocker uses AES encryption with a 128-bit key. On a Core2 machine, clocked at 2.53 GHz, encryption speed should be about 110 MB/s, using one core. The two cores could process about 220 MB/s, assuming perfect data transfer and core synchronization with no overhead, and that nothing requires the CPU in the same time (that one hell of an assumption, actually). The X25-M G2 is announced at 250 MB/s read bandwidth (that's what the specs say), so, in "ideal" conditions, BitLocker necessarily involves a bit of a slowdown.
However read bandwidth is not that important. It matters when you copy huge files, which is not something that you do very often. In everyday work, access time is much more important: as a developer, you create, write, read and delete many files, but they are all small (most of them are much smaller than one megabyte). This is what makes SSD "snappy". Encryption does not impact access time. So my guess is that any performance degradation will be negligible(*).
(*) Here I assume that Microsoft's developers did their job properly.
7-Zip command to create and extract a password-protected ZIP file on Windows?
To fully script-automate:
Create:
7z -mhc=on -mhe=on -pPasswordHere a %ZipDest% %WhatYouWantToZip%
Unzip:
7z x %ZipFile% -pPasswordHere
(Depending, you might need to: Set Path=C:\Program Files\7-Zip;%Path% )
Can't check signature: public key not found
There is a similar problem.it is a tomcat digital signature.
$ gpg --verify apache-tomcat-9.0.16-windows-x64.zip.asc apache-tomcat-9.0.16-windows-
x64.zip
gpg: Signature made 2019?02? 5? 0:32:50
gpg: using RSA key A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: Can't check signature: No public key
but then I use the RSA key it provided to receive the public key to verify.
$ gpg --receive-keys A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: key 10C01C5A2F6059E7: 38 signatures not checked due to missing keys
gpg: key 10C01C5A2F6059E7: public key "Mark E D Thomas <[email protected]>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1
Then successfully.
$ gpg --verify apache-tomcat-9.0.16-windows-x64.zip.asc
gpg: assuming signed data in 'apache-tomcat-9.0.16-windows-x64.zip'
gpg: Signature made 2019?02? 5? 0:32:50
gpg: using RSA key A9C5DF4D22E99998D9875A5110C01C5A2F6059E7
gpg: Good signature from "Mark E D Thomas <[email protected]>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: A9C5 DF4D 22E9 9998 D987 5A51 10C0 1C5A 2F60 59E7
How to Generate Unique Public and Private Key via RSA
The RSACryptoServiceProvider(CspParameters) constructor creates a keypair which is stored in the keystore on the local machine. If you already have a keypair with the specified name, it uses the existing keypair.
It sounds as if you are not interested in having the key stored on the machine.
So use the RSACryptoServiceProvider(Int32) constructor:
public static void AssignNewKey(){
RSA rsa = new RSACryptoServiceProvider(2048); // Generate a new 2048 bit RSA key
string publicPrivateKeyXML = rsa.ToXmlString(true);
string publicOnlyKeyXML = rsa.ToXmlString(false);
// do stuff with keys...
}
EDIT:
Alternatively try setting the PersistKeyInCsp to false:
public static void AssignNewKey(){
const int PROVIDER_RSA_FULL = 1;
const string CONTAINER_NAME = "KeyContainer";
CspParameters cspParams;
cspParams = new CspParameters(PROVIDER_RSA_FULL);
cspParams.KeyContainerName = CONTAINER_NAME;
cspParams.Flags = CspProviderFlags.UseMachineKeyStore;
cspParams.ProviderName = "Microsoft Strong Cryptographic Provider";
rsa = new RSACryptoServiceProvider(cspParams);
rsa.PersistKeyInCsp = false;
string publicPrivateKeyXML = rsa.ToXmlString(true);
string publicOnlyKeyXML = rsa.ToXmlString(false);
// do stuff with keys...
}
How to encrypt String in Java
Here a simple solution with only java.* and javax.crypto.* dependencies for encryption of bytes providing confidentiality and integrity. It shall be indistinguishable under a choosen plaintext attack for short messages in the order of kilobytes.
It uses AES in the GCM mode with no padding, a 128bit key is derived by PBKDF2 with lots of iterations and a static salt from the provided password. This makes sure brute forcing passwords is hard and distributes the entropy over the entire key.
A random initialisation vector (IV) is generated and will be prepended to the ciphertext. Furthermore, the static byte 0x01 is prepended as the first byte as a 'version'.
The entire message goes into the message authentication code (MAC) generated by AES/GCM.
Here it goes, zero external dependencies encryption class providing confidentiality and integrity:
package ch.n1b.tcrypt.utils;
import java.nio.charset.StandardCharsets;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.GCMParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
/**
* This class implements AES-GCM symmetric key encryption with a PBKDF2 derived password.
* It provides confidentiality and integrity of the plaintext.
*
* @author Thomas Richner
* @created 2018-12-07
*/
public class AesGcmCryptor {
// https://crypto.stackexchange.com/questions/26783/ciphertext-and-tag-size-and-iv-transmission-with-aes-in-gcm-mode
private static final byte VERSION_BYTE = 0x01;
private static final int VERSION_BYTE_LENGTH = 1;
private static final int AES_KEY_BITS_LENGTH = 128;
// fixed AES-GCM constants
private static final String GCM_CRYPTO_NAME = "AES/GCM/NoPadding";
private static final int GCM_IV_BYTES_LENGTH = 12;
private static final int GCM_TAG_BYTES_LENGTH = 16;
// can be tweaked, more iterations = more compute intensive to brute-force password
private static final int PBKDF2_ITERATIONS = 1024;
// protects against rainbow tables
private static final byte[] PBKDF2_SALT = hexStringToByteArray("4d3fe0d71d2abd2828e7a3196ea450d4");
public String encryptString(char[] password, String plaintext) throws CryptoException {
byte[] encrypted = null;
try {
encrypted = encrypt(password, plaintext.getBytes(StandardCharsets.UTF_8));
} catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException //
| InvalidAlgorithmParameterException | IllegalBlockSizeException | BadPaddingException //
| InvalidKeySpecException e) {
throw new CryptoException(e);
}
return byteArrayToHexString(encrypted);
}
public String decryptString(char[] password, String ciphertext)
throws CryptoException {
byte[] ct = hexStringToByteArray(ciphertext);
byte[] plaintext = null;
try {
plaintext = decrypt(password, ct);
} catch (AEADBadTagException e) {
throw new CryptoException(e);
} catch ( //
NoSuchPaddingException | NoSuchAlgorithmException | InvalidKeySpecException //
| InvalidKeyException | InvalidAlgorithmParameterException | IllegalBlockSizeException //
| BadPaddingException e) {
throw new CryptoException(e);
}
return new String(plaintext, StandardCharsets.UTF_8);
}
/**
* Decrypts an AES-GCM encrypted ciphertext and is
* the reverse operation of {@link AesGcmCryptor#encrypt(char[], byte[])}
*
* @param password passphrase for decryption
* @param ciphertext encrypted bytes
* @return plaintext bytes
* @throws NoSuchPaddingException
* @throws NoSuchAlgorithmException
* @throws NoSuchProviderException
* @throws InvalidKeySpecException
* @throws InvalidAlgorithmParameterException
* @throws InvalidKeyException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws IllegalArgumentException if the length or format of the ciphertext is bad
* @throws CryptoException
*/
public byte[] decrypt(char[] password, byte[] ciphertext)
throws NoSuchPaddingException, NoSuchAlgorithmException, InvalidKeySpecException,
InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
// input validation
if (ciphertext == null) {
throw new IllegalArgumentException("ciphertext cannot be null");
}
if (ciphertext.length <= VERSION_BYTE_LENGTH + GCM_IV_BYTES_LENGTH + GCM_TAG_BYTES_LENGTH) {
throw new IllegalArgumentException("ciphertext too short");
}
// the version must match, we don't decrypt other versions
if (ciphertext[0] != VERSION_BYTE) {
throw new IllegalArgumentException("wrong version: " + ciphertext[0]);
}
// input seems legit, lets decrypt and check integrity
// derive key from password
SecretKey key = deriveAesKey(password, PBKDF2_SALT, AES_KEY_BITS_LENGTH);
// init cipher
Cipher cipher = Cipher.getInstance(GCM_CRYPTO_NAME);
GCMParameterSpec params = new GCMParameterSpec(GCM_TAG_BYTES_LENGTH * 8,
ciphertext,
VERSION_BYTE_LENGTH,
GCM_IV_BYTES_LENGTH
);
cipher.init(Cipher.DECRYPT_MODE, key, params);
final int ciphertextOffset = VERSION_BYTE_LENGTH + GCM_IV_BYTES_LENGTH;
// add version and IV to MAC
cipher.updateAAD(ciphertext, 0, ciphertextOffset);
// decipher and check MAC
return cipher.doFinal(ciphertext, ciphertextOffset, ciphertext.length - ciphertextOffset);
}
/**
* Encrypts a plaintext with a password.
* <p>
* The encryption provides the following security properties:
* Confidentiality + Integrity
* <p>
* This is achieved my using the AES-GCM AEAD blockmode with a randomized IV.
* <p>
* The tag is calculated over the version byte, the IV as well as the ciphertext.
* <p>
* Finally the encrypted bytes have the following structure:
* <pre>
* +-------------------------------------------------------------------+
* | | | | |
* | version | IV bytes | ciphertext bytes | tag |
* | | | | |
* +-------------------------------------------------------------------+
* Length: 1B 12B len(plaintext) bytes 16B
* </pre>
* Note: There is no padding required for AES-GCM, but this also implies that
* the exact plaintext length is revealed.
*
* @param password password to use for encryption
* @param plaintext plaintext to encrypt
* @throws NoSuchAlgorithmException
* @throws NoSuchProviderException
* @throws NoSuchPaddingException
* @throws InvalidAlgorithmParameterException
* @throws InvalidKeyException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws InvalidKeySpecException
*/
public byte[] encrypt(char[] password, byte[] plaintext)
throws NoSuchAlgorithmException, NoSuchPaddingException,
InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException,
InvalidKeySpecException {
// initialise random and generate IV (initialisation vector)
SecretKey key = deriveAesKey(password, PBKDF2_SALT, AES_KEY_BITS_LENGTH);
final byte[] iv = new byte[GCM_IV_BYTES_LENGTH];
SecureRandom random = SecureRandom.getInstanceStrong();
random.nextBytes(iv);
// encrypt
Cipher cipher = Cipher.getInstance(GCM_CRYPTO_NAME);
GCMParameterSpec spec = new GCMParameterSpec(GCM_TAG_BYTES_LENGTH * 8, iv);
cipher.init(Cipher.ENCRYPT_MODE, key, spec);
// add IV to MAC
final byte[] versionBytes = new byte[]{VERSION_BYTE};
cipher.updateAAD(versionBytes);
cipher.updateAAD(iv);
// encrypt and MAC plaintext
byte[] ciphertext = cipher.doFinal(plaintext);
// prepend VERSION and IV to ciphertext
byte[] encrypted = new byte[1 + GCM_IV_BYTES_LENGTH + ciphertext.length];
int pos = 0;
System.arraycopy(versionBytes, 0, encrypted, 0, VERSION_BYTE_LENGTH);
pos += VERSION_BYTE_LENGTH;
System.arraycopy(iv, 0, encrypted, pos, iv.length);
pos += iv.length;
System.arraycopy(ciphertext, 0, encrypted, pos, ciphertext.length);
return encrypted;
}
/**
* We derive a fixed length AES key with uniform entropy from a provided
* passphrase. This is done with PBKDF2/HMAC256 with a fixed count
* of iterations and a provided salt.
*
* @param password passphrase to derive key from
* @param salt salt for PBKDF2 if possible use a per-key salt, alternatively
* a random constant salt is better than no salt.
* @param keyLen number of key bits to output
* @return a SecretKey for AES derived from a passphrase
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
private SecretKey deriveAesKey(char[] password, byte[] salt, int keyLen)
throws NoSuchAlgorithmException, InvalidKeySpecException {
if (password == null || salt == null || keyLen <= 0) {
throw new IllegalArgumentException();
}
SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA256");
KeySpec spec = new PBEKeySpec(password, salt, PBKDF2_ITERATIONS, keyLen);
SecretKey pbeKey = factory.generateSecret(spec);
return new SecretKeySpec(pbeKey.getEncoded(), "AES");
}
/**
* Helper to convert hex strings to bytes.
* <p>
* May be used to read bytes from constants.
*/
private static byte[] hexStringToByteArray(String s) {
if (s == null) {
throw new IllegalArgumentException("Provided `null` string.");
}
int len = s.length();
if (len % 2 != 0) {
throw new IllegalArgumentException("Invalid length: " + len);
}
byte[] data = new byte[len / 2];
for (int i = 0; i < len - 1; i += 2) {
byte b = (byte) toHexDigit(s, i);
b <<= 4;
b |= toHexDigit(s, i + 1);
data[i / 2] = b;
}
return data;
}
private static int toHexDigit(String s, int pos) {
int d = Character.digit(s.charAt(pos), 16);
if (d < 0) {
throw new IllegalArgumentException("Cannot parse hex digit: " + s + " at " + pos);
}
return d;
}
private static String byteArrayToHexString(byte[] bytes) {
StringBuilder sb = new StringBuilder();
for (byte b : bytes) {
sb.append(String.format("%02X", b));
}
return sb.toString();
}
public class CryptoException extends Exception {
public CryptoException(Throwable cause) {
super(cause);
}
}
}
Here the entire project with a nice CLI: https://github.com/trichner/tcrypt
Edit: now with appropriate encryptString and decryptString
Encrypt Password in Configuration Files?
Well to solve the problems of master password - the best approach is not to store the password anywhere, the application should encrypt passwords for itself - so that only it can decrypt them. So if I was using a .config file I would do the following, mySettings.config:
encryptTheseKeys=secretKey,anotherSecret
secretKey=unprotectedPasswordThatIputHere
anotherSecret=anotherPass
someKey=unprotectedSettingIdontCareAbout
so I would read in the keys that are mentioned in the encryptTheseKeys, apply the Brodwalls example from above on them and write them back to the file with a marker of some sort (lets say crypt:) to let the application know not to do it again, the output would look like this:
encryptTheseKeys=secretKey,anotherSecret
secretKey=crypt:ii4jfj304fjhfj934fouh938
anotherSecret=crypt:jd48jofh48h
someKey=unprotectedSettingIdontCareAbout
Just make sure to keep the originals in your own secure place...
Fast and simple String encrypt/decrypt in JAVA
Update
the library already have Java/Kotlin support, see github.
Original
To simplify I did a class to be used simply, I added it on Encryption library to use it you just do as follow:
Add the gradle library:
compile 'se.simbio.encryption:library:2.0.0'
and use it:
Encryption encryption = Encryption.getDefault("Key", "Salt", new byte[16]);
String encrypted = encryption.encryptOrNull("top secret string");
String decrypted = encryption.decryptOrNull(encrypted);
if you not want add the Encryption library you can just copy the following class to your project. If you are in an android project you need to import android Base64 in this class, if you are in a pure java project you need to add this class manually you can get it here
Encryption.java
package se.simbio.encryption;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
/**
* A class to make more easy and simple the encrypt routines, this is the core of Encryption library
*/
public class Encryption {
/**
* The Builder used to create the Encryption instance and that contains the information about
* encryption specifications, this instance need to be private and careful managed
*/
private final Builder mBuilder;
/**
* The private and unique constructor, you should use the Encryption.Builder to build your own
* instance or get the default proving just the sensible information about encryption
*/
private Encryption(Builder builder) {
mBuilder = builder;
}
/**
* @return an default encryption instance or {@code null} if occur some Exception, you can
* create yur own Encryption instance using the Encryption.Builder
*/
public static Encryption getDefault(String key, String salt, byte[] iv) {
try {
return Builder.getDefaultBuilder(key, salt, iv).build();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
return null;
}
}
/**
* Encrypt a String
*
* @param data the String to be encrypted
*
* @return the encrypted String or {@code null} if you send the data as {@code null}
*
* @throws UnsupportedEncodingException if the Builder charset name is not supported or if
* the Builder charset name is not supported
* @throws NoSuchAlgorithmException if the Builder digest algorithm is not available
* or if this has no installed provider that can
* provide the requested by the Builder secret key
* type or it is {@code null}, empty or in an invalid
* format
* @throws NoSuchPaddingException if no installed provider can provide the padding
* scheme in the Builder digest algorithm
* @throws InvalidAlgorithmParameterException if the specified parameters are inappropriate for
* the cipher
* @throws InvalidKeyException if the specified key can not be used to initialize
* the cipher instance
* @throws InvalidKeySpecException if the specified key specification cannot be used
* to generate a secret key
* @throws BadPaddingException if the padding of the data does not match the
* padding scheme
* @throws IllegalBlockSizeException if the size of the resulting bytes is not a
* multiple of the cipher block size
* @throws NullPointerException if the Builder digest algorithm is {@code null} or
* if the specified Builder secret key type is
* {@code null}
* @throws IllegalStateException if the cipher instance is not initialized for
* encryption or decryption
*/
public String encrypt(String data) throws UnsupportedEncodingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException, InvalidKeySpecException, BadPaddingException, IllegalBlockSizeException {
if (data == null) return null;
SecretKey secretKey = getSecretKey(hashTheKey(mBuilder.getKey()));
byte[] dataBytes = data.getBytes(mBuilder.getCharsetName());
Cipher cipher = Cipher.getInstance(mBuilder.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, secretKey, mBuilder.getIvParameterSpec(), mBuilder.getSecureRandom());
return Base64.encodeToString(cipher.doFinal(dataBytes), mBuilder.getBase64Mode());
}
/**
* This is a sugar method that calls encrypt method and catch the exceptions returning
* {@code null} when it occurs and logging the error
*
* @param data the String to be encrypted
*
* @return the encrypted String or {@code null} if you send the data as {@code null}
*/
public String encryptOrNull(String data) {
try {
return encrypt(data);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* This is a sugar method that calls encrypt method in background, it is a good idea to use this
* one instead the default method because encryption can take several time and with this method
* the process occurs in a AsyncTask, other advantage is the Callback with separated methods,
* one for success and other for the exception
*
* @param data the String to be encrypted
* @param callback the Callback to handle the results
*/
public void encryptAsync(final String data, final Callback callback) {
if (callback == null) return;
new Thread(new Runnable() {
@Override
public void run() {
try {
String encrypt = encrypt(data);
if (encrypt == null) {
callback.onError(new Exception("Encrypt return null, it normally occurs when you send a null data"));
}
callback.onSuccess(encrypt);
} catch (Exception e) {
callback.onError(e);
}
}
}).start();
}
/**
* Decrypt a String
*
* @param data the String to be decrypted
*
* @return the decrypted String or {@code null} if you send the data as {@code null}
*
* @throws UnsupportedEncodingException if the Builder charset name is not supported or if
* the Builder charset name is not supported
* @throws NoSuchAlgorithmException if the Builder digest algorithm is not available
* or if this has no installed provider that can
* provide the requested by the Builder secret key
* type or it is {@code null}, empty or in an invalid
* format
* @throws NoSuchPaddingException if no installed provider can provide the padding
* scheme in the Builder digest algorithm
* @throws InvalidAlgorithmParameterException if the specified parameters are inappropriate for
* the cipher
* @throws InvalidKeyException if the specified key can not be used to initialize
* the cipher instance
* @throws InvalidKeySpecException if the specified key specification cannot be used
* to generate a secret key
* @throws BadPaddingException if the padding of the data does not match the
* padding scheme
* @throws IllegalBlockSizeException if the size of the resulting bytes is not a
* multiple of the cipher block size
* @throws NullPointerException if the Builder digest algorithm is {@code null} or
* if the specified Builder secret key type is
* {@code null}
* @throws IllegalStateException if the cipher instance is not initialized for
* encryption or decryption
*/
public String decrypt(String data) throws UnsupportedEncodingException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidAlgorithmParameterException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
if (data == null) return null;
byte[] dataBytes = Base64.decode(data, mBuilder.getBase64Mode());
SecretKey secretKey = getSecretKey(hashTheKey(mBuilder.getKey()));
Cipher cipher = Cipher.getInstance(mBuilder.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, secretKey, mBuilder.getIvParameterSpec(), mBuilder.getSecureRandom());
byte[] dataBytesDecrypted = (cipher.doFinal(dataBytes));
return new String(dataBytesDecrypted);
}
/**
* This is a sugar method that calls decrypt method and catch the exceptions returning
* {@code null} when it occurs and logging the error
*
* @param data the String to be decrypted
*
* @return the decrypted String or {@code null} if you send the data as {@code null}
*/
public String decryptOrNull(String data) {
try {
return decrypt(data);
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
/**
* This is a sugar method that calls decrypt method in background, it is a good idea to use this
* one instead the default method because decryption can take several time and with this method
* the process occurs in a AsyncTask, other advantage is the Callback with separated methods,
* one for success and other for the exception
*
* @param data the String to be decrypted
* @param callback the Callback to handle the results
*/
public void decryptAsync(final String data, final Callback callback) {
if (callback == null) return;
new Thread(new Runnable() {
@Override
public void run() {
try {
String decrypt = decrypt(data);
if (decrypt == null) {
callback.onError(new Exception("Decrypt return null, it normally occurs when you send a null data"));
}
callback.onSuccess(decrypt);
} catch (Exception e) {
callback.onError(e);
}
}
}).start();
}
/**
* creates a 128bit salted aes key
*
* @param key encoded input key
*
* @return aes 128 bit salted key
*
* @throws NoSuchAlgorithmException if no installed provider that can provide the requested
* by the Builder secret key type
* @throws UnsupportedEncodingException if the Builder charset name is not supported
* @throws InvalidKeySpecException if the specified key specification cannot be used to
* generate a secret key
* @throws NullPointerException if the specified Builder secret key type is {@code null}
*/
private SecretKey getSecretKey(char[] key) throws NoSuchAlgorithmException, UnsupportedEncodingException, InvalidKeySpecException {
SecretKeyFactory factory = SecretKeyFactory.getInstance(mBuilder.getSecretKeyType());
KeySpec spec = new PBEKeySpec(key, mBuilder.getSalt().getBytes(mBuilder.getCharsetName()), mBuilder.getIterationCount(), mBuilder.getKeyLength());
SecretKey tmp = factory.generateSecret(spec);
return new SecretKeySpec(tmp.getEncoded(), mBuilder.getKeyAlgorithm());
}
/**
* takes in a simple string and performs an sha1 hash
* that is 128 bits long...we then base64 encode it
* and return the char array
*
* @param key simple inputted string
*
* @return sha1 base64 encoded representation
*
* @throws UnsupportedEncodingException if the Builder charset name is not supported
* @throws NoSuchAlgorithmException if the Builder digest algorithm is not available
* @throws NullPointerException if the Builder digest algorithm is {@code null}
*/
private char[] hashTheKey(String key) throws UnsupportedEncodingException, NoSuchAlgorithmException {
MessageDigest messageDigest = MessageDigest.getInstance(mBuilder.getDigestAlgorithm());
messageDigest.update(key.getBytes(mBuilder.getCharsetName()));
return Base64.encodeToString(messageDigest.digest(), Base64.NO_PADDING).toCharArray();
}
/**
* When you encrypt or decrypt in callback mode you get noticed of result using this interface
*/
public interface Callback {
/**
* Called when encrypt or decrypt job ends and the process was a success
*
* @param result the encrypted or decrypted String
*/
void onSuccess(String result);
/**
* Called when encrypt or decrypt job ends and has occurred an error in the process
*
* @param exception the Exception related to the error
*/
void onError(Exception exception);
}
/**
* This class is used to create an Encryption instance, you should provide ALL data or start
* with the Default Builder provided by the getDefaultBuilder method
*/
public static class Builder {
private byte[] mIv;
private int mKeyLength;
private int mBase64Mode;
private int mIterationCount;
private String mSalt;
private String mKey;
private String mAlgorithm;
private String mKeyAlgorithm;
private String mCharsetName;
private String mSecretKeyType;
private String mDigestAlgorithm;
private String mSecureRandomAlgorithm;
private SecureRandom mSecureRandom;
private IvParameterSpec mIvParameterSpec;
/**
* @return an default builder with the follow defaults:
* the default char set is UTF-8
* the default base mode is Base64
* the Secret Key Type is the PBKDF2WithHmacSHA1
* the default salt is "some_salt" but can be anything
* the default length of key is 128
* the default iteration count is 65536
* the default algorithm is AES in CBC mode and PKCS 5 Padding
* the default secure random algorithm is SHA1PRNG
* the default message digest algorithm SHA1
*/
public static Builder getDefaultBuilder(String key, String salt, byte[] iv) {
return new Builder()
.setIv(iv)
.setKey(key)
.setSalt(salt)
.setKeyLength(128)
.setKeyAlgorithm("AES")
.setCharsetName("UTF8")
.setIterationCount(1)
.setDigestAlgorithm("SHA1")
.setBase64Mode(Base64.DEFAULT)
.setAlgorithm("AES/CBC/PKCS5Padding")
.setSecureRandomAlgorithm("SHA1PRNG")
.setSecretKeyType("PBKDF2WithHmacSHA1");
}
/**
* Build the Encryption with the provided information
*
* @return a new Encryption instance with provided information
*
* @throws NoSuchAlgorithmException if the specified SecureRandomAlgorithm is not available
* @throws NullPointerException if the SecureRandomAlgorithm is {@code null} or if the
* IV byte array is null
*/
public Encryption build() throws NoSuchAlgorithmException {
setSecureRandom(SecureRandom.getInstance(getSecureRandomAlgorithm()));
setIvParameterSpec(new IvParameterSpec(getIv()));
return new Encryption(this);
}
/**
* @return the charset name
*/
private String getCharsetName() {
return mCharsetName;
}
/**
* @param charsetName the new charset name
*
* @return this instance to follow the Builder patter
*/
public Builder setCharsetName(String charsetName) {
mCharsetName = charsetName;
return this;
}
/**
* @return the algorithm
*/
private String getAlgorithm() {
return mAlgorithm;
}
/**
* @param algorithm the algorithm to be used
*
* @return this instance to follow the Builder patter
*/
public Builder setAlgorithm(String algorithm) {
mAlgorithm = algorithm;
return this;
}
/**
* @return the key algorithm
*/
private String getKeyAlgorithm() {
return mKeyAlgorithm;
}
/**
* @param keyAlgorithm the keyAlgorithm to be used in keys
*
* @return this instance to follow the Builder patter
*/
public Builder setKeyAlgorithm(String keyAlgorithm) {
mKeyAlgorithm = keyAlgorithm;
return this;
}
/**
* @return the Base 64 mode
*/
private int getBase64Mode() {
return mBase64Mode;
}
/**
* @param base64Mode set the base 64 mode
*
* @return this instance to follow the Builder patter
*/
public Builder setBase64Mode(int base64Mode) {
mBase64Mode = base64Mode;
return this;
}
/**
* @return the type of aes key that will be created, on KITKAT+ the API has changed, if you
* are getting problems please @see <a href="http://android-developers.blogspot.com.br/2013/12/changes-to-secretkeyfactory-api-in.html">http://android-developers.blogspot.com.br/2013/12/changes-to-secretkeyfactory-api-in.html</a>
*/
private String getSecretKeyType() {
return mSecretKeyType;
}
/**
* @param secretKeyType the type of AES key that will be created, on KITKAT+ the API has
* changed, if you are getting problems please @see <a href="http://android-developers.blogspot.com.br/2013/12/changes-to-secretkeyfactory-api-in.html">http://android-developers.blogspot.com.br/2013/12/changes-to-secretkeyfactory-api-in.html</a>
*
* @return this instance to follow the Builder patter
*/
public Builder setSecretKeyType(String secretKeyType) {
mSecretKeyType = secretKeyType;
return this;
}
/**
* @return the value used for salting
*/
private String getSalt() {
return mSalt;
}
/**
* @param salt the value used for salting
*
* @return this instance to follow the Builder patter
*/
public Builder setSalt(String salt) {
mSalt = salt;
return this;
}
/**
* @return the key
*/
private String getKey() {
return mKey;
}
/**
* @param key the key.
*
* @return this instance to follow the Builder patter
*/
public Builder setKey(String key) {
mKey = key;
return this;
}
/**
* @return the length of key
*/
private int getKeyLength() {
return mKeyLength;
}
/**
* @param keyLength the length of key
*
* @return this instance to follow the Builder patter
*/
public Builder setKeyLength(int keyLength) {
mKeyLength = keyLength;
return this;
}
/**
* @return the number of times the password is hashed
*/
private int getIterationCount() {
return mIterationCount;
}
/**
* @param iterationCount the number of times the password is hashed
*
* @return this instance to follow the Builder patter
*/
public Builder setIterationCount(int iterationCount) {
mIterationCount = iterationCount;
return this;
}
/**
* @return the algorithm used to generate the secure random
*/
private String getSecureRandomAlgorithm() {
return mSecureRandomAlgorithm;
}
/**
* @param secureRandomAlgorithm the algorithm to generate the secure random
*
* @return this instance to follow the Builder patter
*/
public Builder setSecureRandomAlgorithm(String secureRandomAlgorithm) {
mSecureRandomAlgorithm = secureRandomAlgorithm;
return this;
}
/**
* @return the IvParameterSpec bytes array
*/
private byte[] getIv() {
return mIv;
}
/**
* @param iv the byte array to create a new IvParameterSpec
*
* @return this instance to follow the Builder patter
*/
public Builder setIv(byte[] iv) {
mIv = iv;
return this;
}
/**
* @return the SecureRandom
*/
private SecureRandom getSecureRandom() {
return mSecureRandom;
}
/**
* @param secureRandom the Secure Random
*
* @return this instance to follow the Builder patter
*/
public Builder setSecureRandom(SecureRandom secureRandom) {
mSecureRandom = secureRandom;
return this;
}
/**
* @return the IvParameterSpec
*/
private IvParameterSpec getIvParameterSpec() {
return mIvParameterSpec;
}
/**
* @param ivParameterSpec the IvParameterSpec
*
* @return this instance to follow the Builder patter
*/
public Builder setIvParameterSpec(IvParameterSpec ivParameterSpec) {
mIvParameterSpec = ivParameterSpec;
return this;
}
/**
* @return the message digest algorithm
*/
private String getDigestAlgorithm() {
return mDigestAlgorithm;
}
/**
* @param digestAlgorithm the algorithm to be used to get message digest instance
*
* @return this instance to follow the Builder patter
*/
public Builder setDigestAlgorithm(String digestAlgorithm) {
mDigestAlgorithm = digestAlgorithm;
return this;
}
}
}
How to decrypt a password from SQL server?
You cannot decrypt this password again but there is another method named "pwdcompare". Here is a example how to use it with SQL syntax:
USE TEMPDB
GO
declare @hash varbinary (255)
CREATE TABLE tempdb..h (id_num int, hash varbinary (255))
SET @hash = pwdencrypt('123') -- encryption
INSERT INTO tempdb..h (id_num,hash) VALUES (1,@hash)
SET @hash = pwdencrypt('123')
INSERT INTO tempdb..h (id_num,hash) VALUES (2,@hash)
SELECT TOP 1 @hash = hash FROM tempdb..h WHERE id_num = 2
SELECT pwdcompare ('123', @hash) AS [Success of check] -- Comparison
SELECT * FROM tempdb..h
INSERT INTO tempdb..h (id_num,hash)
VALUES (3,CONVERT(varbinary (255),
0x01002D60BA07FE612C8DE537DF3BFCFA49CD9968324481C1A8A8FE612C8DE537DF3BFCFA49CD9968324481C1A8A8))
SELECT TOP 1 @hash = hash FROM tempdb..h WHERE id_num = 3
SELECT pwdcompare ('123', @hash) AS [Success of check] -- Comparison
SELECT * FROM tempdb..h
DROP TABLE tempdb..h
GO
Encrypt and decrypt a password in Java
Here is the algorithm I use to crypt with MD5.It returns your crypted output.
public class CryptWithMD5 {
private static MessageDigest md;
public static String cryptWithMD5(String pass){
try {
md = MessageDigest.getInstance("MD5");
byte[] passBytes = pass.getBytes();
md.reset();
byte[] digested = md.digest(passBytes);
StringBuffer sb = new StringBuffer();
for(int i=0;i<digested.length;i++){
sb.append(Integer.toHexString(0xff & digested[i]));
}
return sb.toString();
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(CryptWithMD5.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
}
You cannot decrypt MD5, but you can compare outputs since if you put the same string in this method it will have the same crypted output.If you want to decrypt you need to use the SHA.You will never use decription for a users password.For that always use MD5.That exception is pretty redundant.It will never throw it.
How to encrypt and decrypt file in Android?
Use a CipherOutputStream or CipherInputStream with a Cipher and your FileInputStream / FileOutputStream.
I would suggest something like Cipher.getInstance("AES/CBC/PKCS5Padding") for creating the Cipher class. CBC mode is secure and does not have the vulnerabilities of ECB mode for non-random plaintexts. It should be present in any generic cryptographic library, ensuring high compatibility.
Don't forget to use a Initialization Vector (IV) generated by a secure random generator if you want to encrypt multiple files with the same key. You can prefix the plain IV at the start of the ciphertext. It is always exactly one block (16 bytes) in size.
If you want to use a password, please make sure you do use a good key derivation mechanism (look up password based encryption or password based key derivation). PBKDF2 is the most commonly used Password Based Key Derivation scheme and it is present in most Java runtimes, including Android. Note that SHA-1 is a bit outdated hash function, but it should be fine in PBKDF2, and does currently present the most compatible option.
Always specify the character encoding when encoding/decoding strings, or you'll be in trouble when the platform encoding differs from the previous one. In other words, don't use String.getBytes() but use String.getBytes(StandardCharsets.UTF_8).
To make it more secure, please add cryptographic integrity and authenticity by adding a secure checksum (MAC or HMAC) over the ciphertext and IV, preferably using a different key. Without an authentication tag the ciphertext may be changed in such a way that the change cannot be detected.
Be warned that CipherInputStream may not report BadPaddingException, this includes BadPaddingException generated for authenticated ciphers such as GCM. This would make the streams incompatible and insecure for these kind of authenticated ciphers.
Remove 'b' character do in front of a string literal in Python 3
Decoding is redundant
You only had this "error" in the first place, because of a misunderstanding of what's happening.
You get the b because you encoded to utf-8 and now it's a bytes object.
>> type("text".encode("utf-8"))
>> <class 'bytes'>
Fixes:
- You can just print the string first
- Redundantly decode it after encoding
SQLite with encryption/password protection
You can password protect SQLite3 DB. For the first time before doing any operations, set password as follows.
SQLiteConnection conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
conn.SetPassword("password");
conn.open();
then next time you can access it like
conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;Password=password;");
conn.Open();
This wont allow any GUI editor to view Your data.
Later if you wish to change the password, use conn.ChangePassword("new_password");
To reset or remove password, use conn.ChangePassword(String.Empty);
What is the meaning of ToString("X2")?
It formats the string as two uppercase hexadecimal characters.
In more depth, the argument "X2" is a "format string" that tells the ToString() method how it should format the string. In this case, "X2" indicates the string should be formatted in Hexadecimal.
byte.ToString() without any arguments returns the number in its natural decimal representation, with no padding.
Microsoft documents the standard numeric format strings which generally work with all primitive numeric types' ToString() methods. This same pattern is used for other types as well: for example, standard date/time format strings can be used with DateTime.ToString().
Get all messages from Whatsapp
If you really want something simple and know how to write/run Python, take a look at the script Bas Bosschert: sources
#!/usr/bin/env python
import sys
from Crypto.Cipher import AES
try:
wafile=sys.argv[1]
except:
print "Usage: %s <msgstore.db.crypt>" % __file__
sys.exit(1)
key = "346a23652a46392b4d73257c67317e352e3372482177652c".decode('hex')
cipher = AES.new(key,1)
open('msgstore.db',"wb").write(cipher.decrypt(open(wafile,"rb").read()))
Full run:
(scratch)ehtesh@ackee:/tmp/whatsapp$ mkvirtualenv whatsapp_decrypt
New python executable in whatsapp_decrypt/bin/python
Installing setuptools, pip...done.
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ pip install pycrypto >/dev/null
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ wget https://gist.githubusercontent.com/shurane/ffa15e959e2d134086c9/raw/bc99a9997123bea0ea0acde185e24c7e89133559/whatsapp_decrypt.py >/dev/null
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ ls
msgstore.db.crypt whatsapp_decrypt.py
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ python whatsapp_decrypt.py msgstore.db.crypt
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ ls
msgstore.db.crypt msgstore.db whatsapp_decrypt.py
(whatsapp_decrypt)ehtesh@ackee:/tmp/whatsapp$ sqlite3 msgstore.db
SQLite version 3.7.17 2013-05-20 00:56:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> PRAGMA table_info(messages);
0|_id|INTEGER|0||1
1|key_remote_jid|TEXT|1||0
2|key_from_me|INTEGER|0||0
3|key_id|TEXT|1||0
4|status|INTEGER|0||0
5|needs_push|INTEGER|0||0
6|data|TEXT|0||0
7|timestamp|INTEGER|0||0
8|media_url|TEXT|0||0
9|media_mime_type|TEXT|0||0
10|media_wa_type|TEXT|0||0
11|media_size|INTEGER|0||0
12|media_name|TEXT|0||0
13|media_hash|TEXT|0||0
14|media_duration|INTEGER|0||0
15|origin|INTEGER|0||0
16|latitude|REAL|0||0
17|longitude|REAL|0||0
18|thumb_image|TEXT|0||0
19|remote_resource|TEXT|0||0
20|received_timestamp|INTEGER|0||0
21|send_timestamp|INTEGER|0||0
22|receipt_server_timestamp|INTEGER|0||0
23|receipt_device_timestamp|INTEGER|0||0
24|raw_data|BLOB|0||0
25|recipient_count|INTEGER|0||0
sqlite>
Pritam Baral has mentioned an even simpler way:
openssl aes-192-ecb -d -in msgstore.db.crypt -out msgstore.db -K 346a23652a46392b4d73257c67317e352e3372482177652c
How to encrypt/decrypt data in php?
I'm think this has been answered before...but anyway, if you want to encrypt/decrypt data, you can't use SHA256
//Key
$key = 'SuperSecretKey';
//To Encrypt:
$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, 'I want to encrypt this', MCRYPT_MODE_ECB);
//To Decrypt:
$decrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, $encrypted, MCRYPT_MODE_ECB);
How to decrypt an encrypted Apple iTunes iPhone backup?
You should grab a copy of Erica Sadun's mdhelper command line utility (OS X binary & source). It supports listing and extracting the contents of iPhone/iPod Touch backups, including address book & SMS databases, and other application metadata and settings.
Encrypt and Decrypt in Java
You may want to use the jasypt library (Java Simplified Encryption), which is quite easy to use. ( Also, it's recommended to check against the encrypted password rather than decrypting the encrypted password )
To use jasypt, if you're using maven, you can include jasypt into your pom.xml file as follows:
<dependency>
<groupId>org.jasypt</groupId>
<artifactId>jasypt</artifactId>
<version>1.9.3</version>
<scope>compile</scope>
</dependency>
And then to encrypt the password, you can use StrongPasswordEncryptor
public static String encryptPassword(String inputPassword) {
StrongPasswordEncryptor encryptor = new StrongPasswordEncryptor();
return encryptor.encryptPassword(inputPassword);
}
Note: the encrypted password is different every time you call encryptPassword but the checkPassword method can still check that the unencrypted password still matches each of the encrypted passwords.
And to check the unencrypted password against the encrypted password, you can use the checkPassword method:
public static boolean checkPassword(String inputPassword, String encryptedStoredPassword) {
StrongPasswordEncryptor encryptor = new StrongPasswordEncryptor();
return encryptor.checkPassword(inputPassword, encryptedStoredPassword);
}
The page below provides detailed information on the complexities involved in creating safe encrypted passwords.
How to Export Private / Secret ASC Key to Decrypt GPG Files
this ended up working for me:
gpg -a --export-secret-keys > exportedKeyFilename.asc
you can name keyfilename.asc by any name as long as you keep on the .asc extension.
this command copies all secret-keys on a user's computer to keyfilename.asc in the working directory of where the command was called.
To Export just 1 specific secret key instead of all of them:
gpg -a --export-secret-keys keyIDNumber > exportedKeyFilename.asc
keyIDNumber is the number of the key id for the desired key you are trying to export.
Is it possible to decrypt MD5 hashes?
MD5 has its weaknesses (see Wikipedia), so there are some projects, which try to precompute Hashes. Wikipedia does also hint at some of these projects. One I know of (and respect) is ophrack. You can not tell the user their own password, but you might be able to tell them a password that works. But i think: Just mail thrm a new password in case they forgot.
How to create a secure random AES key in Java?
Lots of good advince in the other posts. This is what I use:
Key key;
SecureRandom rand = new SecureRandom();
KeyGenerator generator = KeyGenerator.getInstance("AES");
generator.init(256, rand);
key = generator.generateKey();
If you need another randomness provider, which I sometime do for testing purposes, just replace rand with
MySecureRandom rand = new MySecureRandom();
How to decrypt Hash Password in Laravel
Short answer is that you don't 'decrypt' the password (because it's not encrypted - it's hashed).
The long answer is that you shouldn't send the user their password by email, or any other way. If the user has forgotten their password, you should send them a password reset email, and allow them to change their password on your website.
Laravel has most of this functionality built in (see the Laravel documentation - I'm not going to replicate it all here. Also available for versions 4.2 and 5.0 of Laravel).
For further reading, check out this 'blogoverflow' post: Why passwords should be hashed.
How can I hide or encrypt JavaScript code?
While everyone will generally agree that Javascript encryption is a bad idea, there are a few small use cases where slowing down the attack is better than nothing. You can start with YUI Compressor (as @Ben Alpert) said, or JSMin, Uglify, or many more.
However, the main case in which I want to really 'hide stuff' is when I'm publishing an email address. Note, there is the problem of Chrome when you click on 'inspect element'. It will show your original code: every time. This is why obfuscation is generally regarded as being a better way to go.
On that note, I take a two pronged attack, purely to slow down spam bots. I Obfuscate/minify the js and then run it again through an encoder (again, this second step is completely pointless in chrome).
While not exactly a pure Javascript encoder, the best html encoder I have found is http://hivelogic.com/enkoder/. It will turn this:
<script type="text/javascript">
//<![CDATA[
<!--
var c=function(e) { var m="mail" + "to:webmaster";var a="somedomain"; e.href = m+"@"+a+".com";
};
//-->
//]]>
</script>
<a href="#" onclick="return c(this);"><img src="images/email.png" /></a>
into this:
<script type="text/javascript">
//<![CDATA[
<!--
var x="function f(x){var i,o=\"\",ol=x.length,l=ol;while(x.charCodeAt(l/13)!" +
"=50){try{x+=x;l+=l;}catch(e){}}for(i=l-1;i>=0;i--){o+=x.charAt(i);}return o" +
".substr(0,ol);}f(\")87,\\\"meozp?410\\\\=220\\\\s-dvwggd130\\\\#-2o,V_PY420" +
"\\\\I\\\\\\\\_V[\\\\\\\\620\\\\o710\\\\RB\\\\\\\\610\\\\JAB620\\\\720\\\\n\\"+
"\\{530\\\\410\\\\WJJU010\\\\|>snnn|j5J(771\\\\p{}saa-.W)+T:``vk\\\"\\\\`<02" +
"0\\\\!610\\\\'Dr\\\\010\\\\630\\\\400\\\\620\\\\700\\\\\\\\\\\\N730\\\\,530" +
"\\\\2S16EF600\\\\;420\\\\9ZNONO1200\\\\/000\\\\`'7400\\\\%n\\\\!010\\\\hpr\\"+
"\\= -cn720\\\\a(ce230\\\\500\\\\f730\\\\i,`200\\\\630\\\\[YIR720\\\\]720\\\\"+
"r\\\\720\\\\h][P]@JHADY310\\\\t230\\\\G500\\\\VBT230\\\\200\\\\Clxhh{tzra/{" +
"g0M0$./Pgche%Z8i#p`v^600\\\\\\\\\\\\R730\\\\Q620\\\\030\\\\730\\\\100\\\\72" +
"0\\\\530\\\\700\\\\720\\\\M410\\\\N730\\\\r\\\\530\\\\400\\\\4420\\\\8OM771" +
"\\\\`4400\\\\$010\\\\t\\\\120\\\\230\\\\r\\\\610\\\\310\\\\530\\\\e~o120\\\\"+
"RfJjn\\\\020\\\\lZ\\\\\\\\CZEWCV771\\\\v5lnqf2R1ox771\\\\p\\\"\\\\tr\\\\220" +
"\\\\310\\\\420\\\\600\\\\OSG300\\\\700\\\\410\\\\320\\\\410\\\\120\\\\620\\" +
"\\q)5<: 0>+\\\"(f};o nruter};))++y(^)i(tAedoCrahc.x(edoCrahCmorf.gnirtS=+o;" +
"721=%y;++y)87<i(fi{)++i;l<i;0=i(rof;htgnel.x=l,\\\"\\\"=o,i rav{)y,x(f noit" +
"cnuf\")" ;
while(x=eval(x));
//-->
//]]>
</script>
Maybe it's enough to slow down a few spam bots. I haven't had any spam come through using this (!yet).
How to resolve the "EVP_DecryptFInal_ex: bad decrypt" during file decryption
Errors: "Bad encrypt / decrypt" "gitencrypt_smudge: FAILURE: openssl error decrypting file"
There are various error strings that are thrown from openssl, depending on respective versions, and scenarios. Below is the checklist I use in case of openssl related issues:
- Ideally, openssl is able to encrypt/decrypt using same key (+ salt) & enc algo only.
Ensure that openssl versions (used to encrypt/decrypt), are compatible. For eg. the hash used in openssl changed at version 1.1.0 from MD5 to SHA256. This produces a different key from the same password. Fix: add "-md md5" in 1.1.0 to decrypt data from lower versions, and add "-md sha256 in lower versions to decrypt data from 1.1.0
Ensure that there is a single openssl version installed in your machine. In case there are multiple versions installed simultaneously (in my machine, these were installed :- 'LibreSSL 2.6.5' and 'openssl 1.1.1d'), make the sure that only the desired one appears in your PATH variable.
How to choose an AES encryption mode (CBC ECB CTR OCB CFB)?
- Anything but ECB.
- If using CTR, it is imperative that you use a different IV for each message, otherwise you end up with the attacker being able to take two ciphertexts and deriving a combined unencrypted plaintext. The reason is that CTR mode essentially turns a block cipher into a stream cipher, and the first rule of stream ciphers is to never use the same Key+IV twice.
- There really isn't much difference in how difficult the modes are to implement. Some modes only require the block cipher to operate in the encrypting direction. However, most block ciphers, including AES, don't take much more code to implement decryption.
- For all cipher modes, it is important to use different IVs for each message if your messages could be identical in the first several bytes, and you don't want an attacker knowing this.
What is the difference between encrypting and signing in asymmetric encryption?
Yeah think of signing data as giving it your own wax stamp that nobody else has. It is done to achieve integrity and non-repudiation. Encryption is so no-one else can see the data. This is done to achieve confidentiality. See wikipedia http://en.wikipedia.org/wiki/Information_security#Key_concepts
A signature is a hash of your message signed using your private key.
Example of AES using Crypto++
Official document of Crypto++ AES is a good start. And from my archive, a basic implementation of AES is as follows:
Please refer here with more explanation, I recommend you first understand the algorithm and then try to understand each line step by step.
#include <iostream>
#include <iomanip>
#include "modes.h"
#include "aes.h"
#include "filters.h"
int main(int argc, char* argv[]) {
//Key and IV setup
//AES encryption uses a secret key of a variable length (128-bit, 196-bit or 256-
//bit). This key is secretly exchanged between two parties before communication
//begins. DEFAULT_KEYLENGTH= 16 bytes
CryptoPP::byte key[ CryptoPP::AES::DEFAULT_KEYLENGTH ], iv[ CryptoPP::AES::BLOCKSIZE ];
memset( key, 0x00, CryptoPP::AES::DEFAULT_KEYLENGTH );
memset( iv, 0x00, CryptoPP::AES::BLOCKSIZE );
//
// String and Sink setup
//
std::string plaintext = "Now is the time for all good men to come to the aide...";
std::string ciphertext;
std::string decryptedtext;
//
// Dump Plain Text
//
std::cout << "Plain Text (" << plaintext.size() << " bytes)" << std::endl;
std::cout << plaintext;
std::cout << std::endl << std::endl;
//
// Create Cipher Text
//
CryptoPP::AES::Encryption aesEncryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
CryptoPP::CBC_Mode_ExternalCipher::Encryption cbcEncryption( aesEncryption, iv );
CryptoPP::StreamTransformationFilter stfEncryptor(cbcEncryption, new CryptoPP::StringSink( ciphertext ) );
stfEncryptor.Put( reinterpret_cast<const unsigned char*>( plaintext.c_str() ), plaintext.length() );
stfEncryptor.MessageEnd();
//
// Dump Cipher Text
//
std::cout << "Cipher Text (" << ciphertext.size() << " bytes)" << std::endl;
for( int i = 0; i < ciphertext.size(); i++ ) {
std::cout << "0x" << std::hex << (0xFF & static_cast<CryptoPP::byte>(ciphertext[i])) << " ";
}
std::cout << std::endl << std::endl;
//
// Decrypt
//
CryptoPP::AES::Decryption aesDecryption(key, CryptoPP::AES::DEFAULT_KEYLENGTH);
CryptoPP::CBC_Mode_ExternalCipher::Decryption cbcDecryption( aesDecryption, iv );
CryptoPP::StreamTransformationFilter stfDecryptor(cbcDecryption, new CryptoPP::StringSink( decryptedtext ) );
stfDecryptor.Put( reinterpret_cast<const unsigned char*>( ciphertext.c_str() ), ciphertext.size() );
stfDecryptor.MessageEnd();
//
// Dump Decrypted Text
//
std::cout << "Decrypted Text: " << std::endl;
std::cout << decryptedtext;
std::cout << std::endl << std::endl;
return 0;
}
For installation details :
- How do I install Crypto++ in Visual Studio 2010 Windows 7?
- *nix environment
- For Ubuntu I did:
sudo apt-get install libcrypto++-dev libcrypto++-doc libcrypto++-utils
RSA Public Key format
Starting from the decoded base64 data of an OpenSSL rsa-ssh Key, i've been able to guess a format:
00 00 00 07: four byte length prefix (7 bytes)73 73 68 2d 72 73 61: "ssh-rsa"00 00 00 01: four byte length prefix (1 byte)25: RSA Exponent (e): 2500 00 01 00: four byte length prefix (256 bytes)RSA Modulus (
n):7f 9c 09 8e 8d 39 9e cc d5 03 29 8b c4 78 84 5f d9 89 f0 33 df ee 50 6d 5d d0 16 2c 73 cf ed 46 dc 7e 44 68 bb 37 69 54 6e 9e f6 f0 c5 c6 c1 d9 cb f6 87 78 70 8b 73 93 2f f3 55 d2 d9 13 67 32 70 e6 b5 f3 10 4a f5 c3 96 99 c2 92 d0 0f 05 60 1c 44 41 62 7f ab d6 15 52 06 5b 14 a7 d8 19 a1 90 c6 c1 11 f8 0d 30 fd f5 fc 00 bb a4 ef c9 2d 3f 7d 4a eb d2 dc 42 0c 48 b2 5e eb 37 3c 6c a0 e4 0a 27 f0 88 c4 e1 8c 33 17 33 61 38 84 a0 bb d0 85 aa 45 40 cb 37 14 bf 7a 76 27 4a af f4 1b ad f0 75 59 3e ac df cd fc 48 46 97 7e 06 6f 2d e7 f5 60 1d b1 99 f8 5b 4f d3 97 14 4d c5 5e f8 76 50 f0 5f 37 e7 df 13 b8 a2 6b 24 1f ff 65 d1 fb c8 f8 37 86 d6 df 40 e2 3e d3 90 2c 65 2b 1f 5c b9 5f fa e9 35 93 65 59 6d be 8c 62 31 a9 9b 60 5a 0e e5 4f 2d e6 5f 2e 71 f3 7e 92 8f fe 8b
The closest validation of my theory i can find it from RFC 4253:
The "ssh-rsa" key format has the following specific encoding:
string "ssh-rsa" mpint e mpint nHere the 'e' and 'n' parameters form the signature key blob.
But it doesn't explain the length prefixes.
Taking the random RSA PUBLIC KEY i found (in the question), and decoding the base64 into hex:
30 82 01 0a 02 82 01 01 00 fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68
e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e
11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d
dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80
fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94
23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0
9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3
4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd
41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e
97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f
fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a
63 02 03 01 00 01
From RFC3447 - Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1:
A.1.1 RSA public key syntax
An RSA public key should be represented with the ASN.1 type
RSAPublicKey:RSAPublicKey ::= SEQUENCE { modulus INTEGER, -- n publicExponent INTEGER -- e }The fields of type RSAPublicKey have the following meanings:
- modulus is the RSA modulus n.
- publicExponent is the RSA public exponent e.
Using Microsoft's excellent (and the only real) ASN.1 documentation:
30 82 01 0a ;SEQUENCE (0x010A bytes: 266 bytes)
| 02 82 01 01 ;INTEGER (0x0101 bytes: 257 bytes)
| | 00 ;leading zero because high-bit, but number is positive
| | fb 11 99 ff 07 33 f6 e8 05 a4 fd 3b 36 ca 68
| | e9 4d 7b 97 46 21 16 21 69 c7 15 38 a5 39 37 2e 27 f3 f5 1d f3 b0 8b 2e
| | 11 1c 2d 6b bf 9f 58 87 f1 3a 8d b4 f1 eb 6d fe 38 6c 92 25 68 75 21 2d
| | dd 00 46 87 85 c1 8a 9c 96 a2 92 b0 67 dd c7 1d a0 d5 64 00 0b 8b fd 80
| | fb 14 c1 b5 67 44 a3 b5 c6 52 e8 ca 0e f0 b6 fd a6 4a ba 47 e3 a4 e8 94
| | 23 c0 21 2c 07 e3 9a 57 03 fd 46 75 40 f8 74 98 7b 20 95 13 42 9a 90 b0
| | 9b 04 97 03 d5 4d 9a 1c fe 3e 20 7e 0e 69 78 59 69 ca 5b f5 47 a3 6b a3
| | 4d 7c 6a ef e7 9f 31 4e 07 d9 f9 f2 dd 27 b7 29 83 ac 14 f1 46 67 54 cd
| | 41 26 25 16 e4 a1 5a b1 cf b6 22 e6 51 d3 e8 3f a0 95 da 63 0b d6 d9 3e
| | 97 b0 c8 22 a5 eb 42 12 d4 28 30 02 78 ce 6b a0 cc 74 90 b8 54 58 1f 0f
| | fb 4b a3 d4 23 65 34 de 09 45 99 42 ef 11 5f aa 23 1b 15 15 3d 67 83 7a
| | 63
| 02 03 ;INTEGER (3 bytes)
| 01 00 01
giving the public key modulus and exponent:
- modulus =
0xfb1199ff0733f6e805a4fd3b36ca68...837a63 - exponent = 65,537
Hash function that produces short hashes?
You can use the hashlib library for Python. The shake_128 and shake_256 algorithms provide variable length hashes. Here's some working code (Python3):
import hashlib
>>> my_string = 'hello shake'
>>> hashlib.shake_256(my_string.encode()).hexdigest(5)
'34177f6a0a'
Notice that with a length parameter x (5 in example) the function returns a hash value of length 2x.
gpg decryption fails with no secret key error
You can also be interested at the top answer in here: https://askubuntu.com/questions/1080204/gpg-problem-with-the-agent-permission-denied
basically the solution that worked for me too is:
gpg --decrypt --pinentry-mode=loopback <file>
What is the easiest way to encrypt a password when I save it to the registry?
If it's a password used for authentication by your application, then hash the password as others suggest.
If you're storing passwords for an external resource, you'll often want to be able to prompt the user for these credentials and give him the opportunity to save them securely. Windows provides the Credentials UI (CredUI) for this purpose - there are a number of samples showing how to use this in .NET, including this one on MSDN.
Using SHA1 and RSA with java.security.Signature vs. MessageDigest and Cipher
To produce the same results:
MessageDigest sha1 = MessageDigest.getInstance("SHA1", BOUNCY_CASTLE_PROVIDER);
byte[] digest = sha1.digest(content);
DERObjectIdentifier sha1oid_ = new DERObjectIdentifier("1.3.14.3.2.26");
AlgorithmIdentifier sha1aid_ = new AlgorithmIdentifier(sha1oid_, null);
DigestInfo di = new DigestInfo(sha1aid_, digest);
byte[] plainSig = di.getDEREncoded();
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding", BOUNCY_CASTLE_PROVIDER);
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] signature = cipher.doFinal(plainSig);
Javascript AES encryption
JSAES is a powerful implementation of AES in JavaScript. http://point-at-infinity.org/jsaes/
JSchException: Algorithm negotiation fail
FWIW, I had this same error message under JSch 0.1.50. Upgrading to 0.1.52 solved the problem.
How to convert SecureString to System.String?
Use the System.Runtime.InteropServices.Marshal class:
String SecureStringToString(SecureString value) {
IntPtr valuePtr = IntPtr.Zero;
try {
valuePtr = Marshal.SecureStringToGlobalAllocUnicode(value);
return Marshal.PtrToStringUni(valuePtr);
} finally {
Marshal.ZeroFreeGlobalAllocUnicode(valuePtr);
}
}
If you want to avoid creating a managed string object, you can access the raw data using Marshal.ReadInt16(IntPtr, Int32):
void HandleSecureString(SecureString value) {
IntPtr valuePtr = IntPtr.Zero;
try {
valuePtr = Marshal.SecureStringToGlobalAllocUnicode(value);
for (int i=0; i < value.Length; i++) {
short unicodeChar = Marshal.ReadInt16(valuePtr, i*2);
// handle unicodeChar
}
} finally {
Marshal.ZeroFreeGlobalAllocUnicode(valuePtr);
}
}
Best way to use PHP to encrypt and decrypt passwords?
Security Warning: This class is not secure. It's using Rijndael256-ECB, which is not semantically secure. Just because "it works" doesn't mean "it's secure". Also, it strips tailing spaces afterwards due to not using proper padding.
Found this class recently, it works like a dream!
class Encryption {
var $skey = "yourSecretKey"; // you can change it
public function safe_b64encode($string) {
$data = base64_encode($string);
$data = str_replace(array('+','/','='),array('-','_',''),$data);
return $data;
}
public function safe_b64decode($string) {
$data = str_replace(array('-','_'),array('+','/'),$string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====', $mod4);
}
return base64_decode($data);
}
public function encode($value){
if(!$value){return false;}
$text = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $this->skey, $text, MCRYPT_MODE_ECB, $iv);
return trim($this->safe_b64encode($crypttext));
}
public function decode($value){
if(!$value){return false;}
$crypttext = $this->safe_b64decode($value);
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $this->skey, $crypttext, MCRYPT_MODE_ECB, $iv);
return trim($decrypttext);
}
}
And to call it:
$str = "My secret String";
$converter = new Encryption;
$encoded = $converter->encode($str );
$decoded = $converter->decode($encoded);
echo "$encoded<p>$decoded";
How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?
package com.ezeon.util.gen;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import javax.crypto.*;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
/*** Encryption and Decryption of String data; PBE(Password Based Encryption and Decryption)
* @author Vikram
*/
public class CryptoUtil
{
Cipher ecipher;
Cipher dcipher;
// 8-byte Salt
byte[] salt = {
(byte) 0xA9, (byte) 0x9B, (byte) 0xC8, (byte) 0x32,
(byte) 0x56, (byte) 0x35, (byte) 0xE3, (byte) 0x03
};
// Iteration count
int iterationCount = 19;
public CryptoUtil() {
}
/**
*
* @param secretKey Key used to encrypt data
* @param plainText Text input to be encrypted
* @return Returns encrypted text
* @throws java.security.NoSuchAlgorithmException
* @throws java.security.spec.InvalidKeySpecException
* @throws javax.crypto.NoSuchPaddingException
* @throws java.security.InvalidKeyException
* @throws java.security.InvalidAlgorithmParameterException
* @throws java.io.UnsupportedEncodingException
* @throws javax.crypto.IllegalBlockSizeException
* @throws javax.crypto.BadPaddingException
*
*/
public String encrypt(String secretKey, String plainText)
throws NoSuchAlgorithmException,
InvalidKeySpecException,
NoSuchPaddingException,
InvalidKeyException,
InvalidAlgorithmParameterException,
UnsupportedEncodingException,
IllegalBlockSizeException,
BadPaddingException {
//Key generation for enc and desc
KeySpec keySpec = new PBEKeySpec(secretKey.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
//Enc process
ecipher = Cipher.getInstance(key.getAlgorithm());
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
String charSet = "UTF-8";
byte[] in = plainText.getBytes(charSet);
byte[] out = ecipher.doFinal(in);
String encStr = new String(Base64.getEncoder().encode(out));
return encStr;
}
/**
* @param secretKey Key used to decrypt data
* @param encryptedText encrypted text input to decrypt
* @return Returns plain text after decryption
* @throws java.security.NoSuchAlgorithmException
* @throws java.security.spec.InvalidKeySpecException
* @throws javax.crypto.NoSuchPaddingException
* @throws java.security.InvalidKeyException
* @throws java.security.InvalidAlgorithmParameterException
* @throws java.io.UnsupportedEncodingException
* @throws javax.crypto.IllegalBlockSizeException
* @throws javax.crypto.BadPaddingException
*/
public String decrypt(String secretKey, String encryptedText)
throws NoSuchAlgorithmException,
InvalidKeySpecException,
NoSuchPaddingException,
InvalidKeyException,
InvalidAlgorithmParameterException,
UnsupportedEncodingException,
IllegalBlockSizeException,
BadPaddingException,
IOException {
//Key generation for enc and desc
KeySpec keySpec = new PBEKeySpec(secretKey.toCharArray(), salt, iterationCount);
SecretKey key = SecretKeyFactory.getInstance("PBEWithMD5AndDES").generateSecret(keySpec);
// Prepare the parameter to the ciphers
AlgorithmParameterSpec paramSpec = new PBEParameterSpec(salt, iterationCount);
//Decryption process; same key will be used for decr
dcipher = Cipher.getInstance(key.getAlgorithm());
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
byte[] enc = Base64.getDecoder().decode(encryptedText);
byte[] utf8 = dcipher.doFinal(enc);
String charSet = "UTF-8";
String plainStr = new String(utf8, charSet);
return plainStr;
}
public static void main(String[] args) throws Exception {
CryptoUtil cryptoUtil=new CryptoUtil();
String key="ezeon8547";
String plain="This is an important message";
String enc=cryptoUtil.encrypt(key, plain);
System.out.println("Original text: "+plain);
System.out.println("Encrypted text: "+enc);
String plainAfter=cryptoUtil.decrypt(key, enc);
System.out.println("Original text after decryption: "+plainAfter);
}
}Initial bytes incorrect after Java AES/CBC decryption
Optimized version of the accepted answer.
no 3rd party libs
includes IV into the encrypted message (can be public)
password can be of any length
Code:
import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;
import java.util.Base64;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class Encryptor {
public static byte[] getRandomInitialVector() {
try {
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
SecureRandom randomSecureRandom = SecureRandom.getInstance("SHA1PRNG");
byte[] initVector = new byte[cipher.getBlockSize()];
randomSecureRandom.nextBytes(initVector);
return initVector;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static byte[] passwordTo16BitKey(String password) {
try {
byte[] srcBytes = password.getBytes("UTF-8");
byte[] dstBytes = new byte[16];
if (srcBytes.length == 16) {
return srcBytes;
}
if (srcBytes.length < 16) {
for (int i = 0; i < dstBytes.length; i++) {
dstBytes[i] = (byte) ((srcBytes[i % srcBytes.length]) * (srcBytes[(i + 1) % srcBytes.length]));
}
} else if (srcBytes.length > 16) {
for (int i = 0; i < srcBytes.length; i++) {
dstBytes[i % dstBytes.length] += srcBytes[i];
}
}
return dstBytes;
} catch (UnsupportedEncodingException ex) {
ex.printStackTrace();
}
return null;
}
public static String encrypt(String key, String value) {
return encrypt(passwordTo16BitKey(key), value);
}
public static String encrypt(byte[] key, String value) {
try {
byte[] initVector = Encryptor.getRandomInitialVector();
IvParameterSpec iv = new IvParameterSpec(initVector);
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
byte[] encrypted = cipher.doFinal(value.getBytes());
return Base64.getEncoder().encodeToString(encrypted) + " " + Base64.getEncoder().encodeToString(initVector);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
public static String decrypt(String key, String encrypted) {
return decrypt(passwordTo16BitKey(key), encrypted);
}
public static String decrypt(byte[] key, String encrypted) {
try {
String[] encryptedParts = encrypted.split(" ");
byte[] initVector = Base64.getDecoder().decode(encryptedParts[1]);
if (initVector.length != 16) {
return null;
}
IvParameterSpec iv = new IvParameterSpec(initVector);
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5PADDING");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
byte[] original = cipher.doFinal(Base64.getDecoder().decode(encryptedParts[0]));
return new String(original);
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
}
Usage:
String key = "Password of any length.";
String encrypted = Encryptor.encrypt(key, "Hello World");
String decrypted = Encryptor.decrypt(key, encrypted);
System.out.println(encrypted);
System.out.println(decrypted);
Example output:
QngBg+Qc5+F8HQsksgfyXg== yDfYiIHTqOOjc0HRNdr1Ng==
Hello World
How can I decrypt a password hash in PHP?
it seems someone finally has created a script to decrypt password_hash. checkout this one: https://pastebin.com/Sn19ShVX
<?php
error_reporting(0);
# Coded by L0c4lh34rtz - IndoXploit
# \n -> linux
# \r\n -> windows
$list = explode("\n", file_get_contents($argv[1])); # change \n to \r\n if you're using windows
# ------------------- #
$hash = '$2y$10$BxO1iVD3HYjVO83NJ58VgeM4wNc7gd3gpggEV8OoHzB1dOCThBpb6'; # hash here, NB: use single quote (') , don't use double quote (")
if(isset($argv[1])) {
foreach($list as $wordlist) {
print " [+]"; print (password_verify($wordlist, $hash)) ? "$hash -> $wordlist (OK)\n" : "$hash -> $wordlist (SALAH)\n";
}
} else {
print "usage: php ".$argv[0]." wordlist.txt\n";
}
?>
Decrypt password created with htpasswd
See in particular Apache HTTPd Password Formats
AES Encryption for an NSString on the iPhone
Since you haven't posted any code, it's difficult to know exactly which problems you're encountering. However, the blog post you link to does seem to work pretty decently... aside from the extra comma in each call to CCCrypt() which caused compile errors.
A later comment on that post includes this adapted code, which works for me, and seems a bit more straightforward. If you include their code for the NSData category, you can write something like this: (Note: The printf() calls are only for demonstrating the state of the data at various points — in a real application, it wouldn't make sense to print such values.)
int main (int argc, const char * argv[]) {
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *key = @"my password";
NSString *secret = @"text to encrypt";
NSData *plain = [secret dataUsingEncoding:NSUTF8StringEncoding];
NSData *cipher = [plain AES256EncryptWithKey:key];
printf("%s\n", [[cipher description] UTF8String]);
plain = [cipher AES256DecryptWithKey:key];
printf("%s\n", [[plain description] UTF8String]);
printf("%s\n", [[[NSString alloc] initWithData:plain encoding:NSUTF8StringEncoding] UTF8String]);
[pool drain];
return 0;
}
Given this code, and the fact that encrypted data will not always translate nicely into an NSString, it may be more convenient to write two methods that wrap the functionality you need, in forward and reverse...
- (NSData*) encryptString:(NSString*)plaintext withKey:(NSString*)key {
return [[plaintext dataUsingEncoding:NSUTF8StringEncoding] AES256EncryptWithKey:key];
}
- (NSString*) decryptData:(NSData*)ciphertext withKey:(NSString*)key {
return [[[NSString alloc] initWithData:[ciphertext AES256DecryptWithKey:key]
encoding:NSUTF8StringEncoding] autorelease];
}
This definitely works on Snow Leopard, and @Boz reports that CommonCrypto is part of the Core OS on the iPhone. Both 10.4 and 10.5 have /usr/include/CommonCrypto, although 10.5 has a man page for CCCryptor.3cc and 10.4 doesn't, so YMMV.
EDIT: See this follow-up question on using Base64 encoding for representing encrypted data bytes as a string (if desired) using safe, lossless conversions.
Fundamental difference between Hashing and Encryption algorithms
You already got some good answers, but I guess you could see it like this: ENCRYPTION: Encryption has to be decryptable if you have the right key.
Example: Like when you send an e-mail. You might not want everyone in the world to know what you are writing to the person receiving the e-mail, but the person who receives the e-mail would probably want to be able to read it.
HASHES: hashes work similar like encryption, but it should not be able to reverse it at all.
Example: Like when you put a key in a locked door(the kinds that locks when you close them). You do not care how the lock works in detail, just as long as it unlocks itself when you use the key. If there is trouble you probably cannot fix it, instead get a new lock.(like forgetting passwords on every login, at least I do it all the time and it is a common area to use hashing).
... and I guess you could call that rainbow-algorithm a locksmith in this case.
Hope things clear up =)
Java AES encryption and decryption
Try this, a simpler solution.
byte[] salt = "ThisIsASecretKey".getBytes();
Key key = new SecretKeySpec(salt, 0, 16, "AES");
Cipher cipher = Cipher.getInstance("AES");
How do you test a public/private DSA keypair?
Assuming you have the public keys inside X.509 certificates, and assuming they are RSA keys, then for each public key, do
openssl x509 -in certfile -modulus -noout
For each private key, do
openssl rsa -in keyfile -modulus -noout
Then match the keys by modulus.
Difference between Hashing a Password and Encrypting it
Hashing is a one way function (well, a mapping). It's irreversible, you apply the secure hash algorithm and you cannot get the original string back. The most you can do is to generate what's called "a collision", that is, finding a different string that provides the same hash. Cryptographically secure hash algorithms are designed to prevent the occurrence of collisions. You can attack a secure hash by the use of a rainbow table, which you can counteract by applying a salt to the hash before storing it.
Encrypting is a proper (two way) function. It's reversible, you can decrypt the mangled string to get original string if you have the key.
The unsafe functionality it's referring to is that if you encrypt the passwords, your application has the key stored somewhere and an attacker who gets access to your database (and/or code) can get the original passwords by getting both the key and the encrypted text, whereas with a hash it's impossible.
People usually say that if a cracker owns your database or your code he doesn't need a password, thus the difference is moot. This is naïve, because you still have the duty to protect your users' passwords, mainly because most of them do use the same password over and over again, exposing them to a greater risk by leaking their passwords.
How do I use 3DES encryption/decryption in Java?
I had hard times figuring it out myself and this post helped me to find the right answer for my case. When working with financial messaging as ISO-8583 the 3DES requirements are quite specific, so for my especial case the "DESede/CBC/PKCS5Padding" combinations wasn't solving the problem. After some comparative testing of my results against some 3DES calculators designed for the financial world I found the the value "DESede/ECB/Nopadding" is more suited for the the specific task.
Here is a demo implementation of my TripleDes class (using the Bouncy Castle provider)
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.Security;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
/**
*
* @author Jose Luis Montes de Oca
*/
public class TripleDesCipher {
private static String TRIPLE_DES_TRANSFORMATION = "DESede/ECB/Nopadding";
private static String ALGORITHM = "DESede";
private static String BOUNCY_CASTLE_PROVIDER = "BC";
private Cipher encrypter;
private Cipher decrypter;
public TripleDesCipher(byte[] key) throws NoSuchAlgorithmException, NoSuchProviderException, NoSuchPaddingException,
InvalidKeyException {
Security.addProvider(new BouncyCastleProvider());
SecretKey keySpec = new SecretKeySpec(key, ALGORITHM);
encrypter = Cipher.getInstance(TRIPLE_DES_TRANSFORMATION, BOUNCY_CASTLE_PROVIDER);
encrypter.init(Cipher.ENCRYPT_MODE, keySpec);
decrypter = Cipher.getInstance(TRIPLE_DES_TRANSFORMATION, BOUNCY_CASTLE_PROVIDER);
decrypter.init(Cipher.DECRYPT_MODE, keySpec);
}
public byte[] encode(byte[] input) throws IllegalBlockSizeException, BadPaddingException {
return encrypter.doFinal(input);
}
public byte[] decode(byte[] input) throws IllegalBlockSizeException, BadPaddingException {
return decrypter.doFinal(input);
}
}
Simple way to encode a string according to a password?
External libraries provide secret-key encryption algorithms.
For example, the Cypher module in PyCrypto offers a selection of many encryption algorithms:
Crypto.Cipher.AESCrypto.Cipher.ARC2Crypto.Cipher.ARC4Crypto.Cipher.BlowfishCrypto.Cipher.CASTCrypto.Cipher.DESCrypto.Cipher.DES3Crypto.Cipher.IDEACrypto.Cipher.RC5Crypto.Cipher.XOR
MeTooCrypto is a Python wrapper for OpenSSL, and provides (among other functions) a full-strength general purpose cryptography library. Included are symmetric ciphers (like AES).
Are HTTPS headers encrypted?
With SSL the encryption is at the transport level, so it takes place before a request is sent.
So everything in the request is encrypted.
Simplest two-way encryption using PHP
IMPORTANT this answer is valid only for PHP 5, in PHP 7 use built-in cryptographic functions.
Here is simple but secure enough implementation:
- AES-256 encryption in CBC mode
- PBKDF2 to create encryption key out of plain-text password
- HMAC to authenticate the encrypted message.
Code and examples are here: https://stackoverflow.com/a/19445173/1387163
PHP AES encrypt / decrypt
If you are using PHP >= 7.2 consider using inbuilt sodium core extension for encrption.
Find more information here - http://php.net/manual/en/intro.sodium.php.
Encrypt and decrypt a String in java
public String encrypt(String str) {
try {
// Encode the string into bytes using utf-8
byte[] utf8 = str.getBytes("UTF8");
// Encrypt
byte[] enc = ecipher.doFinal(utf8);
// Encode bytes to base64 to get a string
return new sun.misc.BASE64Encoder().encode(enc);
} catch (javax.crypto.BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (java.io.IOException e) {
}
return null;
}
public String decrypt(String str) {
try {
// Decode base64 to get bytes
byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);
// Decrypt
byte[] utf8 = dcipher.doFinal(dec);
// Decode using utf-8
return new String(utf8, "UTF8");
} catch (javax.crypto.BadPaddingException e) {
} catch (IllegalBlockSizeException e) {
} catch (UnsupportedEncodingException e) {
} catch (java.io.IOException e) {
}
return null;
}
}
Here's an example that uses the class:
try {
// Generate a temporary key. In practice, you would save this key.
// See also Encrypting with DES Using a Pass Phrase.
SecretKey key = KeyGenerator.getInstance("DES").generateKey();
// Create encrypter/decrypter class
DesEncrypter encrypter = new DesEncrypter(key);
// Encrypt
String encrypted = encrypter.encrypt("Don't tell anybody!");
// Decrypt
String decrypted = encrypter.decrypt(encrypted);
} catch (Exception e) {
}
Encrypt & Decrypt using PyCrypto AES 256
You can get a passphrase out of an arbitrary password by using a cryptographic hash function (NOT Python's builtin hash) like SHA-1 or SHA-256. Python includes support for both in its standard library:
import hashlib
hashlib.sha1("this is my awesome password").digest() # => a 20 byte string
hashlib.sha256("another awesome password").digest() # => a 32 byte string
You can truncate a cryptographic hash value just by using [:16] or [:24] and it will retain its security up to the length you specify.
Is it possible to hide/encode/encrypt php source code and let others have the system?
You could just split the frontend and backend. The frontend is hosted on the customers server with an API that makes calls to the backend on your server. This keeps all of the proprietary code proprietary and forces users to sign up / pay for subscriptions.
How do I generate a SALT in Java for Salted-Hash?
Inspired from this post and that post, I use this code to generate and verify hashed salted passwords. It only uses JDK provided classes, no external dependency.
The process is:
- you create a salt with
getNextSalt - you ask the user his password and use the
hashmethod to generate a salted and hashed password. The method returns abyte[]which you can save as is in a database with the salt - to authenticate a user, you ask his password, retrieve the salt and hashed password from the database and use the
isExpectedPasswordmethod to check that the details match
/**
* A utility class to hash passwords and check passwords vs hashed values. It uses a combination of hashing and unique
* salt. The algorithm used is PBKDF2WithHmacSHA1 which, although not the best for hashing password (vs. bcrypt) is
* still considered robust and <a href="https://security.stackexchange.com/a/6415/12614"> recommended by NIST </a>.
* The hashed value has 256 bits.
*/
public class Passwords {
private static final Random RANDOM = new SecureRandom();
private static final int ITERATIONS = 10000;
private static final int KEY_LENGTH = 256;
/**
* static utility class
*/
private Passwords() { }
/**
* Returns a random salt to be used to hash a password.
*
* @return a 16 bytes random salt
*/
public static byte[] getNextSalt() {
byte[] salt = new byte[16];
RANDOM.nextBytes(salt);
return salt;
}
/**
* Returns a salted and hashed password using the provided hash.<br>
* Note - side effect: the password is destroyed (the char[] is filled with zeros)
*
* @param password the password to be hashed
* @param salt a 16 bytes salt, ideally obtained with the getNextSalt method
*
* @return the hashed password with a pinch of salt
*/
public static byte[] hash(char[] password, byte[] salt) {
PBEKeySpec spec = new PBEKeySpec(password, salt, ITERATIONS, KEY_LENGTH);
Arrays.fill(password, Character.MIN_VALUE);
try {
SecretKeyFactory skf = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
return skf.generateSecret(spec).getEncoded();
} catch (NoSuchAlgorithmException | InvalidKeySpecException e) {
throw new AssertionError("Error while hashing a password: " + e.getMessage(), e);
} finally {
spec.clearPassword();
}
}
/**
* Returns true if the given password and salt match the hashed value, false otherwise.<br>
* Note - side effect: the password is destroyed (the char[] is filled with zeros)
*
* @param password the password to check
* @param salt the salt used to hash the password
* @param expectedHash the expected hashed value of the password
*
* @return true if the given password and salt match the hashed value, false otherwise
*/
public static boolean isExpectedPassword(char[] password, byte[] salt, byte[] expectedHash) {
byte[] pwdHash = hash(password, salt);
Arrays.fill(password, Character.MIN_VALUE);
if (pwdHash.length != expectedHash.length) return false;
for (int i = 0; i < pwdHash.length; i++) {
if (pwdHash[i] != expectedHash[i]) return false;
}
return true;
}
/**
* Generates a random password of a given length, using letters and digits.
*
* @param length the length of the password
*
* @return a random password
*/
public static String generateRandomPassword(int length) {
StringBuilder sb = new StringBuilder(length);
for (int i = 0; i < length; i++) {
int c = RANDOM.nextInt(62);
if (c <= 9) {
sb.append(String.valueOf(c));
} else if (c < 36) {
sb.append((char) ('a' + c - 10));
} else {
sb.append((char) ('A' + c - 36));
}
}
return sb.toString();
}
}
How do I instantiate a Queue object in java?
Queue is an interface; you can't explicitly construct a Queue. You'll have to instantiate one of its implementing classes. Something like:
Queue linkedList = new LinkedList();
How to open my files in data_folder with pandas using relative path?
For non-Windows users:
import pandas as pd
import os
os.chdir("../data_folder")
df = pd.read_csv("data.csv")
For Windows users:
import pandas as pd
df = pd.read_csv(r"C:\data_folder\data.csv")
The prefix r in location above saves time when giving the location to the pandas Dataframe.
How to add anchor tags dynamically to a div in Javascript?
var newA = document.createElement('a');
newA.setAttribute('href',"http://localhost");
newA.innerHTML = "link text";
document.appendChild(newA);
Is CSS Turing complete?
This answer is not accurate because it mix description of UTM and UTM itself (Universal Turing Machine).
We have good answer but from different perspective and it do not show directly flaws in current top answer.
First of all we can agree that human can work as UTM. This mean if we do
CSS + Human == UTM
Then CSS part is useless because all work can be done by Human who will do UTM part. Act of clicking can be UTM, because you do not click at random but only in specific places.
Instead of CSS I could use this text (Rule 110):
000 -> 0
001 -> 1
010 -> 1
011 -> 1
100 -> 0
101 -> 1
110 -> 1
111 -> 0
To guide my actions and result will be same. This mean this text UTM? No this is only input (description) that other UTM (human or computer) can read and run. Clicking is enough to run any UTM.
Critical part that CSS lack is ability to change of it own state in arbitrary way, if CSS could generate clicks then it would be UTM. Argument that your clicks are "crank" for CSS is not accurate because real "crank" for CSS is Layout Engine that run it and it should be enough to prove that CSS is UTM.
How to extract .war files in java? ZIP vs JAR
Like you said, a jar is a zip file (not a special type, but just a plain old zip), so either library could be made to work. The reasoning is that the average person, seeing a *.zip extension, tends to unzip it. Since the app server wants it unzipped, a simple rename keeps people from unzipping it simply out of habit. Likewise, *.war file also should remain uncompressed.
java.util.jar basically just adds additional functionality to java.util.zip with very little extra overhead. Let the java.util.jar be a helper in posting, etc... and use it.
SQLite select where empty?
It looks like you can simply do:
SELECT * FROM your_table WHERE some_column IS NULL OR some_column = '';
Test case:
CREATE TABLE your_table (id int, some_column varchar(10));
INSERT INTO your_table VALUES (1, NULL);
INSERT INTO your_table VALUES (2, '');
INSERT INTO your_table VALUES (3, 'test');
INSERT INTO your_table VALUES (4, 'another test');
INSERT INTO your_table VALUES (5, NULL);
Result:
SELECT id FROM your_table WHERE some_column IS NULL OR some_column = '';
id
----------
1
2
5
Can I set a TTL for @Cacheable
this can be done by extending org.springframework.cache.interceptor.CacheInterceptor , and override "doPut" method - org.springframework.cache.interceptor.AbstractCacheInvoker your override logic should use the cache provider put method that knows to set TTL for cache entry (in my case I use HazelcastCacheManager)
@Autowired
@Qualifier(value = "cacheManager")
private CacheManager hazelcastCacheManager;
@Override
protected void doPut(Cache cache, Object key, Object result) {
//super.doPut(cache, key, result);
HazelcastCacheManager hazelcastCacheManager = (HazelcastCacheManager) this.hazelcastCacheManager;
HazelcastInstance hazelcastInstance = hazelcastCacheManager.getHazelcastInstance();
IMap<Object, Object> map = hazelcastInstance.getMap("CacheName");
//set time to leave 18000 secondes
map.put(key, result, 18000, TimeUnit.SECONDS);
}
on your cache configuration you need to add those 2 bean methods , creating your custom interceptor instance .
@Bean
public CacheOperationSource cacheOperationSource() {
return new AnnotationCacheOperationSource();
}
@Primary
@Bean
public CacheInterceptor cacheInterceptor() {
CacheInterceptor interceptor = new MyCustomCacheInterceptor();
interceptor.setCacheOperationSources(cacheOperationSource());
return interceptor;
}
This solution is good when you want to set the TTL on the entry level , and not globally on cache level
How to change my Git username in terminal?
If you have created a new Github account and you want to push commits with your new account instead of your previous account then the .gitconfig must be updated, otherwise, you will push with the already owned Github account to the new account.
In order to fix this, you have to navigate to your home directory and open the .gitconfig with an editor. The editor can be vim, notepad++, or even notepad.
Once you have the .gitconfig open, just modify the "name" with your new Github account username that you want to push with.
Getting the textarea value of a ckeditor textarea with javascript
I'm still having problems figuring out exactly how I find out what a user is typing into a ckeditor textarea.
Ok, this is fairly easy. Assuming your editor is named "editor1", this will give you an alert with your its contents:
alert(CKEDITOR.instances.editor1.getData());
The harder part is detecting when the user types. From what I can tell, there isn't actually support to do that (and I'm not too impressed with the documentation btw). See this article: http://alfonsoml.blogspot.com/2011/03/onchange-event-for-ckeditor.html
Instead, I would suggest setting a timer that is going to continuously update your second div with the value of the textarea:
timer = setInterval(updateDiv,100);
function updateDiv(){
var editorText = CKEDITOR.instances.editor1.getData();
$('#trackingDiv').html(editorText);
}
This seems to work just fine. Here's the entire thing for clarity:
<textarea id="editor1" name="editor1">This is sample text</textarea>
<div id="trackingDiv" ></div>
<script type="text/javascript">
CKEDITOR.replace( 'editor1' );
timer = setInterval(updateDiv,100);
function updateDiv(){
var editorText = CKEDITOR.instances.editor1.getData();
$('#trackingDiv').html(editorText);
}
</script>
What is the difference between concurrency and parallelism?
Imagine learning a new programming language by watching a video tutorial. You need to pause the video, apply what been said in code then continue watching. That's concurrency.
Now you're a professional programmer. And you enjoy listening to calm music while coding. That's Parallelism.
As Andrew Gerrand said in GoLang Blog
Concurrency is about dealing with lots of things at once. Parallelism is about doing lots of things at once.
Enjoy.
"Could not find a valid gem in any repository" (rubygame and others)
It is a permission issue.
try with sudo
C# JSON Serialization of Dictionary into {key:value, ...} instead of {key:key, value:value, ...}
Json.NET does this...
Dictionary<string, string> values = new Dictionary<string, string>();
values.Add("key1", "value1");
values.Add("key2", "value2");
string json = JsonConvert.SerializeObject(values);
// {
// "key1": "value1",
// "key2": "value2"
// }
More examples: Serializing Collections with Json.NET
You should not use <Link> outside a <Router>
You can put the Link component inside the Router componet. Something like this:
<Router>
<Route path='/complete-profiles' component={Profiles} />
<Link to='/complete-profiles'>
<div>Completed Profiles</div>
</Link>
</Router>
Git SSH error: "Connect to host: Bad file number"
In my case the IP address of our git host had changed.
Simply flushing the DNS cache fixed the problem.
JavaScript isset() equivalent
function isset(variable) {
try {
return typeof eval(variable) !== 'undefined';
} catch (err) {
return false;
}
}
Xamarin 2.0 vs Appcelerator Titanium vs PhoneGap
Overview
As reported by Tim Anderson
Cross-platform development is a big deal, and will continue to be so until a day comes when everyone uses the same platform. Android? HTML? WebKit? iOS? Windows? Xamarin? Titanum? PhoneGap? Corona? ecc.
Sometimes I hear it said that there are essentially two approaches to cross-platform mobile apps. You can either use an embedded browser control and write a web app wrapped as a native app, as in Adobe PhoneGap/Cordova or the similar approach taken by Sencha, or you can use a cross-platform tool that creates native apps, such as Xamarin Studio, Appcelerator Titanium, or Embarcardero FireMonkey.
Within the second category though, there is diversity. In particular, they vary concerning the extent to which they abstract the user interface.
Here is the trade-off. If you design your cross-platform framework you can have your application work almost the same way on every platform. If you are sharing the UI design across all platforms, it is hard to make your design feel equally right in all cases. It might be better to take the approach adopted by most games, using a design that is distinctive to your app and make a virtue of its consistency across platforms, even though it does not have the native look and feel on any platform.
edit Xamarin v3 in 2014 started offering choice of Xamarin.Forms as well as pure native that still follows the philosophy mentioned here (took liberty of inline edit because such a great answer)
Xamarin Studio on the other hand makes no attempt to provide a shared GUI framework:
We don’t try to provide a user interface abstraction layer that works across all the platforms. We think that’s a bad approach that leads to lowest common denominator user interfaces. (Nat Friedman to Tim Anderson)
This is right; but the downside is the effort involved in maintaining two or more user interface designs for your app.
Comparison about PhoneGap and Titanium it's well reported in Kevin Whinnery blog.
PhoneGap
The purpose of PhoneGap is to allow HTML-based web applications to be deployed and installed as native applications. PhoneGap web applications are wrapped in a native application shell, and can be installed via the native app stores for multiple platforms. Additionally, PhoneGap strives to provide a common native API set which is typically unavailable to web applications, such as basic camera access, device contacts, and sensors not already exposed in the browser.
To develop PhoneGap applications, developers will create HTML, CSS, and JavaScript files in a local directory, much like developing a static website. Approaching native-quality UI performance in the browser is a non-trivial task - Sencha employs a large team of web programming experts dedicated full-time to solving this problem. Even so, on most platforms, in most browsers today, reaching native-quality UI performance and responsiveness is simply not possible, even with a framework as advanced as Sencha Touch. Is the browser already “good enough” though? It depends on your requirements and sensibilities, but it is unquestionably less good than native UI. Sometimes much worse, depending on the browser.
PhoneGap is not as truly cross-platform as one might believe, not all features are equally supported on all platforms.
Javascript is not an application scale programming language, too many global scope interactions, different libraries don't often co-exist nicely. We spent many hours trying to get knockout.js and jQuery.mobile play well together, and we still have problems.
Fragmented landscape for frameworks and libraries. Too many choices, and too many are not mature enough.
Strangely enough, for the needs of our app, decent performance could be achieved (not with jQuery.Mobile, though). We tried jqMobi (not very mature, but fast).
Very limited capability for interaction with other apps or cdevice capabilities, and this would not be cross-platform anyway, as there aren't any standards in HTML5 except for a few, like geolocation, camera and local databases.
Appcelerator Titanium
The goal of Titanium Mobile is to provide a high level, cross-platform JavaScript runtime and API for mobile development (today we support iOS, Android and Windows Phone. Titanium actually has more in common with MacRuby/Hot Cocoa, PHP, or node.js than it does with PhoneGap, Adobe AIR, Corona, or Rhomobile. Titanium is built on two assertions about mobile development: - There is a core of mobile development APIs which can be normalized across platforms. These areas should be targeted for code reuse. - There are platform-specific APIs, UI conventions, and features which developers should incorporate when developing for that platform. Platform-specific code should exist for these use cases to provide the best possible experience.
So for those reasons, Titanium is not an attempt at “write once, run everywhere”. Same as Xamarin.
Titanium are going to do a further step in the direction similar to that of Xamarin. In practice, they will do two layers of different depths: the layer Titanium (in JS), which gives you a bee JS-of-Titanium. If you want to go more low-level, have created an additional layer (called Hyperloop), where (always with JS) to call you back directly to native APIs of SO
Xamarin (+ MVVMCross)
Xamarin (originally a division of Novell) in the last 18 months has brought to market its own IDE and snap-in for Visual Studio. The underlining premise of Mono is to create disparate mobile applications using C# while maintaining native UI development strategies.
In addition to creating a visual design platform to develop native applications, they have integrated testing suites, incorporated native library support and a Nuget style component store. Recently they provided iOS visual design through their IDE freeing the developer from opening XCode. In Visual Studio all three platforms are now supported and a cloud testing suite is on the horizon.
From the get go, Xamarin has provided a rich Android visual design experience. I have yet to download or open Eclipse or any other IDE besides Xamarin. What is truly amazing is that I am able to use LINQ to work with collections as well as create custom delegates and events that free me from objective-C and Java limitations. Many of the libraries I have been spoiled with, like Newtonsoft JSON.Net, work perfectly in all three environments.
In my opinion there are several HUGE advantages including
- native performance
- easier to read code (IMO)
- testability
- shared code between client and server
- support (although Xam could do better on bugzilla)
Upgrade for me is use Xamarin and MVVMCross combined. It's still quite a new framework, but it's born from experience of several other frameworks (such as MvvmLight and monocross) and it's now been used in at several released cross platform projects.
Conclusion
My choice after knowing all these framwework, was to select development tool based on product needs. In general, however if you start to use a tool with which you feel comfortable (even if it requires a higher initial overhead) after you'll use it forever.
I chose Xamarin + MVVMCross and I must say to be happy with this choice. I'm not afraid of approach Native SDK for software updates or seeing limited functionality of a system or the most trivial thing a feature graphics. Write code fairly structured (DDD + SOA) is very useful to have a core project shared with native C# views implementation.
References and links
- http://www.theregister.co.uk/Print/2013/02/25/cross_platform_abstraction/
- http://kevinwhinnery.com/post/22764624253/comparing-titanium-and-phonegap
- http://forums.xamarin.com/discussion/1003/your-opinion-about-several-crossplatform-frameworks#Comment_3334
- http://azdevelop.azurewebsites.net/?page_id=181
- https://github.com/MvvmCross/MvvmCross
- http://pierceboggan.com/post/51671827932/binding-third-party-objective-c-libraries-in
500 internal server error at GetResponse()
In my case my request object inherited from base object. Without knowingly I added a property with int? in my request object and my base object also has same property ( same name ) with int datatype. I noticed this and deleted the property which I added in request object and after that it worked fine.
When should iteritems() be used instead of items()?
In Python 2.x - .items() returned a list of (key, value) pairs. In Python 3.x, .items() is now an itemview object, which behaves different - so it has to be iterated over, or materialised... So, list(dict.items()) is required for what was dict.items() in Python 2.x.
Python 2.7 also has a bit of a back-port for key handling, in that you have viewkeys, viewitems and viewvalues methods, the most useful being viewkeys which behaves more like a set (which you'd expect from a dict).
Simple example:
common_keys = list(dict_a.viewkeys() & dict_b.viewkeys())
Will give you a list of the common keys, but again, in Python 3.x - just use .keys() instead.
Python 3.x has generally been made to be more "lazy" - i.e. map is now effectively itertools.imap, zip is itertools.izip, etc.
Align text to the bottom of a div
You now can do this with Flexbox justify-content: flex-end now:
div {_x000D_
display: flex;_x000D_
justify-content: flex-end;_x000D_
align-items: flex-end;_x000D_
width: 150px;_x000D_
height: 150px;_x000D_
border: solid 1px red;_x000D_
}_x000D_
<div>_x000D_
Something to align_x000D_
</div>Consult your Caniuse to see if Flexbox is right for you.
How to run vi on docker container?
If you actually want a small editor for simple housekeeping in a docker, use this in your Dockerfile:
RUN apt-get install -y busybox && ln -s /bin/busybox /bin/vi
I used it on an Ubuntu 18 based docker.
(Of course you might need an RUN apt-get update before it but if you are making your own Docker file you probably already have that.)
Reactjs: Unexpected token '<' Error
UPDATE: In React 0.12+, the JSX pragma is no longer necessary.
Make sure include the JSX pragma at the top of your files:
/** @jsx React.DOM */
Without this line, the jsx binary and in-browser transformer will leave your files unchanged.
How do I invoke a Java method when given the method name as a string?
You should use reflection - init a class object, then a method in this class, and then invoke this method on an object with optional parameters. Remember to wrap the following snippet in try-catch block
Hope it helps!
Class<?> aClass = Class.forName(FULLY_QUALIFIED_CLASS_NAME);
Method method = aClass.getMethod(methodName, YOUR_PARAM_1.class, YOUR_PARAM_2.class);
method.invoke(OBJECT_TO_RUN_METHOD_ON, YOUR_PARAM_1, YOUR_PARAM_2);
Don't reload application when orientation changes
Xion's answer was close, but #3 (android:configChanes="orientation") won't work unless the application has an API level of 12 or lower.
In API level 13 or above, the screen size changes when the orientation changes, so this still causes the activity to be destroyed and started when orientation changes.
Simply add the "screenSize" attribute like I did below:
<activity
android:name=".YourActivityName"
android:configChanges="orientation|screenSize">
</activity>
Now, when you change orientation (and screen size changes), the activity keeps its state and onConfigurationChanged() is called. This will keep whatever is on the screen (ie: webpage in a Webview) when the orientation changes.
Learned this from this site: http://developer.android.com/guide/topics/manifest/activity-element.html
Also, this is apparently a bad practice so read the link below about Handling Runtime Changes:
http://developer.android.com/guide/topics/resources/runtime-changes.html
How to use EOF to run through a text file in C?
How you detect EOF depends on what you're using to read the stream:
function result on EOF or error
-------- ----------------------
fgets() NULL
fscanf() number of succesful conversions
less than expected
fgetc() EOF
fread() number of elements read
less than expected
Check the result of the input call for the appropriate condition above, then call feof() to determine if the result was due to hitting EOF or some other error.
Using fgets():
char buffer[BUFFER_SIZE];
while (fgets(buffer, sizeof buffer, stream) != NULL)
{
// process buffer
}
if (feof(stream))
{
// hit end of file
}
else
{
// some other error interrupted the read
}
Using fscanf():
char buffer[BUFFER_SIZE];
while (fscanf(stream, "%s", buffer) == 1) // expect 1 successful conversion
{
// process buffer
}
if (feof(stream))
{
// hit end of file
}
else
{
// some other error interrupted the read
}
Using fgetc():
int c;
while ((c = fgetc(stream)) != EOF)
{
// process c
}
if (feof(stream))
{
// hit end of file
}
else
{
// some other error interrupted the read
}
Using fread():
char buffer[BUFFER_SIZE];
while (fread(buffer, sizeof buffer, 1, stream) == 1) // expecting 1
// element of size
// BUFFER_SIZE
{
// process buffer
}
if (feof(stream))
{
// hit end of file
}
else
{
// some other error interrupted read
}
Note that the form is the same for all of them: check the result of the read operation; if it failed, then check for EOF. You'll see a lot of examples like:
while(!feof(stream))
{
fscanf(stream, "%s", buffer);
...
}
This form doesn't work the way people think it does, because feof() won't return true until after you've attempted to read past the end of the file. As a result, the loop executes one time too many, which may or may not cause you some grief.
Get class list for element with jQuery
A bit late, but using the extend() function lets you call "hasClass()" on any element, e.g.:
var hasClass = $('#divId').hasClass('someClass');
(function($) {
$.extend({
hasClass: new function(className) {
var classAttr = $J(this).attr('class');
if (classAttr != null && classAttr != undefined) {
var classList = classAttr.split(/\s+/);
for(var ix = 0, len = classList.length;ix < len;ix++) {
if (className === classList[ix]) {
return true;
}
}
}
return false;
}
}); })(jQuery);
Python: Finding differences between elements of a list
>>> t
[1, 3, 6]
>>> [j-i for i, j in zip(t[:-1], t[1:])] # or use itertools.izip in py2k
[2, 3]
How to push objects in AngularJS between ngRepeat arrays
Try this one also...
<!DOCTYPE html>_x000D_
<html>_x000D_
_x000D_
<body>_x000D_
_x000D_
<p>Click the button to join two arrays.</p>_x000D_
_x000D_
<button onclick="myFunction()">Try it</button>_x000D_
_x000D_
<p id="demo"></p>_x000D_
<p id="demo1"></p>_x000D_
<script>_x000D_
function myFunction() {_x000D_
var hege = [{_x000D_
1: "Cecilie",_x000D_
2: "Lone"_x000D_
}];_x000D_
var stale = [{_x000D_
1: "Emil",_x000D_
2: "Tobias"_x000D_
}];_x000D_
var hege = hege.concat(stale);_x000D_
document.getElementById("demo1").innerHTML = hege;_x000D_
document.getElementById("demo").innerHTML = stale;_x000D_
}_x000D_
</script>_x000D_
_x000D_
</body>_x000D_
_x000D_
</html>Delete all rows in table
I would suggest using TRUNCATE TABLE, it's quicker and uses less resources than DELETE FROM xxx
Here's the related MSDN article
Is it possible to change the radio button icon in an android radio button group
Here's probably a quick approach,
With two icons shown above, you shall have a RadioGroup something like this
- change the
RadioGroup's orientation to horizontal - for each
RadioButton's Properties, try giving the icon forButtonunderCompoundButton, - adjust the Padding and size,
- and set the Background attribute when checked.
Pass Arraylist as argument to function
The answer is already posted but note that this will pass the ArrayList by reference. So if you make any changes to the list in the function it will be affected to the original list also.
<access-modfier> <returnType> AnalyseArray(ArrayList<Integer> list)
{
//analyse the list
//return value
}
call it like this:
x=AnalyseArray(list);
or pass a copy of ArrayList:
x=AnalyseArray(list.clone());
Visual Studio Code pylint: Unable to import 'protorpc'
Open the settings file of your Visual Studio Code (settings.json) and add the library path to the "python.autoComplete.extraPaths" list.
"python.autoComplete.extraPaths": [
"~/google-cloud-sdk/platform/google_appengine/lib/webapp2-2.5.2",
"~/google-cloud-sdk/platform/google_appengine",
"~/google-cloud-sdk/lib",
"~/google-cloud-sdk/platform/google_appengine/lib/endpoints-1.0",
"~/google-cloud-sdk/platform/google_appengine/lib/protorpc-1.0"
],
How to check if an alert exists using WebDriver?
public boolean isAlertPresent() {
try
{
driver.switchTo().alert();
system.out.println(" Alert Present");
}
catch (NoAlertPresentException e)
{
system.out.println("No Alert Present");
}
}
How can I mock an ES6 module import using Jest?
Adding more to Andreas' answer. I had the same problem with ES6 code, but I did not want to mutate the imports. That looked hacky. So I did this:
import myModule from '../myModule';
import dependency from '../dependency';
jest.mock('../dependency');
describe('myModule', () => {
it('calls the dependency with double the input', () => {
myModule(2);
});
});
And added file dependency.js in the " __ mocks __" folder parallel to file dependency.js. This worked for me. Also, this gave me the option to return suitable data from the mock implementation. Make sure you give the correct path to the module you want to mock.
ReactNative: how to center text?
this is a example for Horizontal and Vertical alignment simultaneously
<View style={{width: 200, flexDirection: 'row',alignItems: 'center'}}>
<Text style={{width: '100%',textAlign: 'center'}} />
</View>
How to implement if-else statement in XSLT?
You have to reimplement it using <xsl:choose> tag:
<xsl:choose>
<xsl:when test="$CreatedDate > $IDAppendedDate">
<h2> mooooooooooooo </h2>
</xsl:when>
<xsl:otherwise>
<h2> dooooooooooooo </h2>
</xsl:otherwise>
</xsl:choose>
Pass variables from servlet to jsp
If you are using Action, Actionforward way to process business logic and next page to show, check out if redirect is called. As many others pointed out, redirecting doesn't keep your original request since it is basically forcing you to make a new request to designated path. So the value set in original request will be vanished if you use redirection instead of requestdispatch.
LINQ query to return a Dictionary<string, string>
Use the ToDictionary method directly.
var result =
// as Jon Skeet pointed out, OrderBy is useless here, I just leave it
// show how to use OrderBy in a LINQ query
myClassCollection.OrderBy(mc => mc.SomePropToSortOn)
.ToDictionary(mc => mc.KeyProp.ToString(),
mc => mc.ValueProp.ToString(),
StringComparer.OrdinalIgnoreCase);
Exception is never thrown in body of corresponding try statement
Always remember that in case of checked exception you can catch only after throwing the exception(either you throw or any inbuilt method used in your code can throw) ,but in case of unchecked exception You an catch even when you have not thrown that exception.
Max size of URL parameters in _GET
See What is the maximum length of a URL in different browsers?
The length of the url can't be changed in PHP. The linked question is about the URL size limit, you will find what you want.
How do I get list of methods in a Python class?
I know this is an old post, but just wrote this function and will leave it here is case someone stumbles looking for an answer:
def classMethods(the_class,class_only=False,instance_only=False,exclude_internal=True):
def acceptMethod(tup):
#internal function that analyzes the tuples returned by getmembers tup[1] is the
#actual member object
is_method = inspect.ismethod(tup[1])
if is_method:
bound_to = tup[1].im_self
internal = tup[1].im_func.func_name[:2] == '__' and tup[1].im_func.func_name[-2:] == '__'
if internal and exclude_internal:
include = False
else:
include = (bound_to == the_class and not instance_only) or (bound_to == None and not class_only)
else:
include = False
return include
#uses filter to return results according to internal function and arguments
return filter(acceptMethod,inspect.getmembers(the_class))
Running sites on "localhost" is extremely slow
I just changed my hosts file from this:
127.0.0.1 abc.com.au
127.0.0.1 def.com.au
127.0.0.1 hij.com.au
to
127.0.0.1 abc.com.au def.com.au hij.com.au
Note: The concatenated website line cant exceed a couple of hundred characters.
How to center an iframe horizontally?
You can put iframe inside a <div>
<div>
<iframe></iframe>
</div>
It works because it is now inside a block element.
SQL: Insert all records from one table to another table without specific the columns
Use this
SELECT *
INTO new_table_name
FROM current_table_name
How can I find a specific element in a List<T>?
Use a lambda expression
MyClass result = list.Find(x => x.GetId() == "xy");
Note: C# has a built-in syntax for properties. Instead of writing getter and setter methods (as you might be used to from Java), write
private string _id;
public string Id
{
get
{
return _id;
}
set
{
_id = value;
}
}
value is a contextual keyword known only in the set accessor. It represents the value assigned to the property.
Since this pattern is often used, C# provides auto-implemented properties. They are a short version of the code above; however, the backing variable is hidden and not accessible (it is accessible from within the class in VB, however).
public string Id { get; set; }
You can simply use properties as if you were accessing a field:
var obj = new MyClass();
obj.Id = "xy"; // Calls the setter with "xy" assigned to the value parameter.
string id = obj.Id; // Calls the getter.
Using properties, you would search for items in the list like this
MyClass result = list.Find(x => x.Id == "xy");
You can also use auto-implemented properties if you need a read-only property:
public string Id { get; private set; }
This enables you to set the Id within the class but not from outside. If you need to set it in derived classes as well you can also protect the setter
public string Id { get; protected set; }
And finally, you can declare properties as virtual and override them in deriving classes, allowing you to provide different implementations for getters and setters; just as for ordinary virtual methods.
Since C# 6.0 (Visual Studio 2015, Roslyn) you can write getter-only auto-properties with an inline initializer
public string Id { get; } = "A07"; // Evaluated once when object is initialized.
You can also initialize getter-only properties within the constructor instead. Getter-only auto-properties are true read-only properties, unlike auto-implemented properties with a private setter.
This works also with read-write auto-properties:
public string Id { get; set; } = "A07";
Beginning with C# 6.0 you can also write properties as expression-bodied members
public DateTime Yesterday => DateTime.Date.AddDays(-1); // Evaluated at each call.
// Instead of
public DateTime Yesterday { get { return DateTime.Date.AddDays(-1); } }
See: .NET Compiler Platform ("Roslyn")
New Language Features in C# 6
Starting with C# 7.0, both, getter and setter, can be written with expression bodies:
public string Name
{
get => _name; // getter
set => _name = value; // setter
}
Note that in this case the setter must be an expression. It cannot be a statement. The example above works, because in C# an assignment can be used as an expression or as a statement. The value of an assignment expression is the assigned value where the assignment itself is a side effect. This allows you to assign a value to more than one variable at once: x = y = z = 0 is equivalent to x = (y = (z = 0)) and has the same effect as the statements x = 0; y = 0; z = 0;.
The next version of the language, C# 9.0, probably available in November 2020, will allow read-only (or better initialize-once) properties that you can initialize in an object initializer. This is currently not possible with getter-only properties.
public string Name { get; init; }
var c = new C { Name = "c-sharp" };
Bootstrap dropdown not working
I just added JS part of bootstrap to my index page, then it worked
Paste this, if you're using the latest version of bootstrap
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js" integrity="sha384-ho+j7jyWK8fNQe+A12Hb8AhRq26LrZ/JpcUGGOn+Y7RsweNrtN/tE3MoK7ZeZDyx" crossorigin="anonymous"></script>
Check if string contains \n Java
If the string was constructed in the same program, I would recommend using this:
String newline = System.getProperty("line.separator");
boolean hasNewline = word.contains(newline);
But if you are specced to use \n, this driver illustrates what to do:
class NewLineTest {
public static void main(String[] args) {
String hasNewline = "this has a newline\n.";
String noNewline = "this doesn't";
System.out.println(hasNewline.contains("\n"));
System.out.println(hasNewline.contains("\\n"));
System.out.println(noNewline.contains("\n"));
System.out.println(noNewline.contains("\\n"));
}
}
Resulted in
true
false
false
false
In reponse to your comment:
class NewLineTest {
public static void main(String[] args) {
String word = "test\n.";
System.out.println(word.length());
System.out.println(word);
word = word.replace("\n","\n ");
System.out.println(word.length());
System.out.println(word);
}
}
Results in
6
test
.
7
test
.
Chmod 777 to a folder and all contents
If you are going for a console command it would be:
chmod -R 777 /www/store. The -R (or --recursive) options make it recursive.
Or if you want to make all the files in the current directory have all permissions type:
chmod -R 777 ./
If you need more info about chmod command see: File permission
Where is Maven's settings.xml located on Mac OS?
If you use brew to install maven, then the settings file should be in
/usr/local/Cellar/maven/<version>/libexec/conf
Get list from pandas dataframe column or row?
If your column will only have one value something like pd.series.tolist() will produce an error. To guarantee that it will work for all cases, use the code below:
(
df
.filter(['column_name'])
.values
.reshape(1, -1)
.ravel()
.tolist()
)
Call to undefined function mysql_query() with Login
You are mixing mysql and mysqli
Change these lines:
$sql = mysql_query("SELECT * FROM login WHERE username = '".$_POST['username']."' and password = '".md5($_POST['password'])."'");
$row = mysql_num_rows($sql);
to
$sql = mysqli_query($success, "SELECT * FROM login WHERE username = '".$_POST['username']."' and password = '".md5($_POST['password'])."'");
$row = mysqli_num_rows($sql);
ESLint Parsing error: Unexpected token
Originally, the solution was to provide the following config as object destructuring used to be an experimental feature and not supported by default:
{
"parserOptions": {
"ecmaFeatures": {
"experimentalObjectRestSpread": true
}
}
}
Since version 5, this option has been deprecated.
Now it is enough just to declare a version of ES, which is new enough:
{
"parserOptions": {
"ecmaVersion": 2018
}
}
Return value in a Bash function
Git Bash on Windows using arrays for multiple return values
BASH CODE:
#!/bin/bash
##A 6-element array used for returning
##values from functions:
declare -a RET_ARR
RET_ARR[0]="A"
RET_ARR[1]="B"
RET_ARR[2]="C"
RET_ARR[3]="D"
RET_ARR[4]="E"
RET_ARR[5]="F"
function FN_MULTIPLE_RETURN_VALUES(){
##give the positional arguments/inputs
##$1 and $2 some sensible names:
local out_dex_1="$1" ##output index
local out_dex_2="$2" ##output index
##Echo for debugging:
echo "running: FN_MULTIPLE_RETURN_VALUES"
##Here: Calculate output values:
local op_var_1="Hello"
local op_var_2="World"
##set the return values:
RET_ARR[ $out_dex_1 ]=$op_var_1
RET_ARR[ $out_dex_2 ]=$op_var_2
}
echo "FN_MULTIPLE_RETURN_VALUES EXAMPLES:"
echo "-------------------------------------------"
fn="FN_MULTIPLE_RETURN_VALUES"
out_dex_a=0
out_dex_b=1
eval $fn $out_dex_a $out_dex_b ##<--Call function
a=${RET_ARR[0]} && echo "RET_ARR[0]: $a "
b=${RET_ARR[1]} && echo "RET_ARR[1]: $b "
echo
##----------------------------------------------##
c="2"
d="3"
FN_MULTIPLE_RETURN_VALUES $c $d ##<--Call function
c_res=${RET_ARR[2]} && echo "RET_ARR[2]: $c_res "
d_res=${RET_ARR[3]} && echo "RET_ARR[3]: $d_res "
echo
##----------------------------------------------##
FN_MULTIPLE_RETURN_VALUES 4 5 ##<---Call function
e=${RET_ARR[4]} && echo "RET_ARR[4]: $e "
f=${RET_ARR[5]} && echo "RET_ARR[5]: $f "
echo
##----------------------------------------------##
read -p "Press Enter To Exit:"
EXPECTED OUTPUT:
FN_MULTIPLE_RETURN_VALUES EXAMPLES:
-------------------------------------------
running: FN_MULTIPLE_RETURN_VALUES
RET_ARR[0]: Hello
RET_ARR[1]: World
running: FN_MULTIPLE_RETURN_VALUES
RET_ARR[2]: Hello
RET_ARR[3]: World
running: FN_MULTIPLE_RETURN_VALUES
RET_ARR[4]: Hello
RET_ARR[5]: World
Press Enter To Exit:
How to configure Visual Studio to use Beyond Compare
Visual Studio with Git for Windows
If you're using GIT as your source code management system instead of the (fairly dated) TFVC then Visual Studio doesn't have options to configure anything like this.
Instead it (rightly in my opinion) uses the GIT config file's setting. So if you already have GIT setup to use Beyond Compare or any other third party comparison software it will just pick this up and start using it.
If not then just set that up (see here for further and likely more up to date help). The relevant info for setting up Visual Studio with Beyond Compare 4 is:
- Open Visual Studio.
- Select Options from the Tools menu.
- Select Plug-In Settings under the Source Control branch of the left-side tree control.
- Select Microsoft Git Provider under Plug-In Settings on the right-hand pane.
- Edit the global git config file (location is OS specific for windows it's
%HOMEDRIVE%%HOMEPATH%/.gitconfig. See here for info) OR if you want it to be repo specifict then after starting a project in a Git repository, edit the config file in the .git folder in the project folder. Change the config file to reflect the following changes:
[diff] tool = bc4 [difftool "bc4"] cmd = \"C:\\Program Files (x86)\\Beyond Compare 4\\BComp.exe\" \"$LOCAL\" \"$REMOTE\" [merge] tool = bc4 [mergetool "bc4"] cmd = \"C:\\Program Files (x86)\\Beyond Compare 4\\BComp.exe\" \"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\"
If 64bit installer is used, verify the name of the executable. Mine was BCompare.exe
[diff]
tool = bc4
[difftool "bc4"]
cmd = \"C:\\Program Files\\Beyond Compare 4\\BCompare.exe\" \"$LOCAL\" \"$REMOTE\"
[merge]
tool = bc4
[mergetool "bc4"]
cmd = \"C:\\Program Files\\Beyond Compare 4\\BCompare.exe\" \"$REMOTE\" \"$LOCAL\" \"$BASE\" \"$MERGED\"
Issues: If you create a new project and get VS to create the git repo at
the same time it WILL add a load of overrides to the .git/config file
forcing it to use Visual Studio again (Thanks for that MS!).
SO either create the git repo via another means after the project has been setup
(like via SourceTree or the command line etc...) OR edit the .git/config file
(in the solution folder) and remove any overrides for the above settings.
Thanks to minnow in the comments for bringing my attention to it again.
Note: I keep coming across this but I am using VS with GIT and the answers aren't correct and although some of the comments mention a URL with the correct answer it's not clear and if I kept missing it I'm sure others will so hopefully this will solve that issue.
How do I change the hover over color for a hover over table in Bootstrap?
.table-hover tbody tr:hover td {
background: #ffffff;
}
What is the use of static synchronized method in java?
In simple words a static synchronized method will lock the class instead of the object, and it will lock the class because the keyword static means: "class instead of instance".
The keyword synchronized means that only one thread can access the method at a time.
And static synchronized mean:
Only one thread can access the class at one time.
Post a json object to mvc controller with jquery and ajax
What am I doing incorrectly?
You have to convert html to javascript object, and then as a second step to json throug JSON.Stringify.
How can I receive a json object in the controller?
View:
<script src="https://code.jquery.com/jquery-3.1.0.js"></script>
<script src="https://raw.githubusercontent.com/marioizquierdo/jquery.serializeJSON/master/jquery.serializejson.js"></script>
var obj = $("#form1").serializeJSON({ useIntKeysAsArrayIndex: true });
$.post("http://localhost:52161/Default/PostRawJson/", { json: JSON.stringify(obj) });
<form id="form1" method="post">
<input name="OrderDate" type="text" /><br />
<input name="Item[0][Id]" type="text" /><br />
<input name="Item[1][Id]" type="text" /><br />
<button id="btn" onclick="btnClick()">Button</button>
</form>
Controller:
public void PostRawJson(string json)
{
var order = System.Web.Helpers.Json.Decode(json);
var orderDate = order.OrderDate;
var secondOrderId = order.Item[1].Id;
}
How to reload the current state?
$state.go($state.current, $stateParams, {reload: true, inherit: false});
How to display all elements in an arraylist?
You can use arraylistname.clone()
Android: where are downloaded files saved?
In my experience all the files which i have downloaded from internet,gmail are stored in
/sdcard/download
on ics
/sdcard/Download
You can access it using
Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
"multiple target patterns" Makefile error
Besides having to escape colons as in the original answer, I have found if the indentation is off you could potentially get the same problem. In one makefile, I had to replace spaces with a tab and that allowed me to get past the error.
How to duplicate a whole line in Vim?
I like: Shift+v (to select the whole line immediately and let you select other lines if you want), y, p
How do I revert an SVN commit?
svn merge -c -M PATH
This saved my life.
I was having the same issue, after reverting back also I was not seeing old code. After running the above command I got a clean old version code.
How to include "zero" / "0" results in COUNT aggregate?
The problem with a LEFT JOIN is that if there are no appointments, it will still return one row with a null, which when aggregated by COUNT will become 1, and it will appear that the person has one appointment when actually they have none. I think this will give the correct results:
SELECT person.person_id,
(SELECT COUNT(*) FROM appointment WHERE person.person_id = appointment.person_id) AS 'Appointments'
FROM person;
Package name does not correspond to the file path - IntelliJ
Add this to pom.xml(inside the project tag)
<build>
<sourceDirectory>src/main/java</sourceDirectory>
</build>
src/main/java is the source folder you want to set. If you already have this line in your pom.xml file, check if it's correct.
What's the difference between echo, print, and print_r in PHP?
print_r() is used for printing the array in human readable format.
In Python, how do I read the exif data for an image?
I use this:
import os,sys
from PIL import Image
from PIL.ExifTags import TAGS
for (k,v) in Image.open(sys.argv[1])._getexif().items():
print('%s = %s' % (TAGS.get(k), v))
or to get a specific field:
def get_field (exif,field) :
for (k,v) in exif.items():
if TAGS.get(k) == field:
return v
exif = image._getexif()
print get_field(exif,'ExposureTime')
Pass a string parameter in an onclick function
Here is a jQuery solution that I'm using.
jQuery
$("#slideshow button").click(function(){
var val = $(this).val();
console.log(val);
});
HTML
<div id="slideshow">
<img src="image1.jpg">
<button class="left" value="back">❮</button>
<button class="right" value="next">❯</button>
</div>
Make a negative number positive
In kotlin you can use unaryPlus
input = input.unaryPlus()
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-int/unary-plus.html
Pandas column of lists, create a row for each list element
I found the easiest way was to:
- Convert the
samplescolumn into a DataFrame - Joining with the original df
- Melting
Shown here:
df.samples.apply(lambda x: pd.Series(x)).join(df).\
melt(['subject','trial_num'],[0,1,2],var_name='sample')
subject trial_num sample value
0 1 1 0 -0.24
1 1 2 0 0.14
2 1 3 0 -0.67
3 2 1 0 -1.52
4 2 2 0 -0.00
5 2 3 0 -1.73
6 1 1 1 -0.70
7 1 2 1 -0.70
8 1 3 1 -0.29
9 2 1 1 -0.70
10 2 2 1 -0.72
11 2 3 1 1.30
12 1 1 2 -0.55
13 1 2 2 0.10
14 1 3 2 -0.44
15 2 1 2 0.13
16 2 2 2 -1.44
17 2 3 2 0.73
It's worth noting that this may have only worked because each trial has the same number of samples (3). Something more clever may be necessary for trials of different sample sizes.
Custom exception type
Here is how you can create custom errors with completely identical to native Error's behaviour. This technique works only in Chrome and node.js for now. I also wouldn't recommend to use it if you don't understand what it does.
Error.createCustromConstructor = (function() {
function define(obj, prop, value) {
Object.defineProperty(obj, prop, {
value: value,
configurable: true,
enumerable: false,
writable: true
});
}
return function(name, init, proto) {
var CustomError;
proto = proto || {};
function build(message) {
var self = this instanceof CustomError
? this
: Object.create(CustomError.prototype);
Error.apply(self, arguments);
Error.captureStackTrace(self, CustomError);
if (message != undefined) {
define(self, 'message', String(message));
}
define(self, 'arguments', undefined);
define(self, 'type', undefined);
if (typeof init == 'function') {
init.apply(self, arguments);
}
return self;
}
eval('CustomError = function ' + name + '() {' +
'return build.apply(this, arguments); }');
CustomError.prototype = Object.create(Error.prototype);
define(CustomError.prototype, 'constructor', CustomError);
for (var key in proto) {
define(CustomError.prototype, key, proto[key]);
}
Object.defineProperty(CustomError.prototype, 'name', { value: name });
return CustomError;
}
})();
As a reasult we get
/**
* name The name of the constructor name
* init User-defined initialization function
* proto It's enumerable members will be added to
* prototype of created constructor
**/
Error.createCustromConstructor = function(name, init, proto)
Then you can use it like this:
var NotImplementedError = Error.createCustromConstructor('NotImplementedError');
And use NotImplementedError as you would Error:
throw new NotImplementedError();
var err = new NotImplementedError();
var err = NotImplementedError('Not yet...');
And it will behave is expected:
err instanceof NotImplementedError // -> true
err instanceof Error // -> true
NotImplementedError.prototype.isPrototypeOf(err) // -> true
Error.prototype.isPrototypeOf(err) // -> true
err.constructor.name // -> NotImplementedError
err.name // -> NotImplementedError
err.message // -> Not yet...
err.toString() // -> NotImplementedError: Not yet...
err.stack // -> works fine!
Note, that error.stack works absolutle correct and won't include NotImplementedError constructor call (thanks to v8's Error.captureStackTrace()).
Note. There is ugly eval(). The only reason it is used is to get correct err.constructor.name. If you don't need it, you can a bit simplify everything.
C++, copy set to vector
set<T> s;
//....
vector<T> v;
v.assign(s.begin(), s.end());
How does one represent the empty char?
The empty space char would be ' '. If you're looking for null that would be '\0'.
How do you express binary literals in Python?
I've tried this in Python 3.6.9
Convert Binary to Decimal
>>> 0b101111
47
>>> int('101111',2)
47
Convert Decimal to binary
>>> bin(47)
'0b101111'
Place a 0 as the second parameter python assumes it as decimal.
>>> int('101111',0)
101111
How can I add an empty directory to a Git repository?
Adding one more option to the fray.
Assuming you would like to add a directory to git that, for all purposes related to git, should remain empty and never have it's contents tracked, a .gitignore as suggested numerous times here, will do the trick.
The format, as mentioned, is:
*
!.gitignore
Now, if you want a way to do this at the command line, in one fell swoop, while inside the directory you want to add, you can execute:
$ echo "*" > .gitignore && echo '!.gitignore' >> .gitignore && git add .gitignore
Myself, I have a shell script that I use to do this. Name the script whatever you whish, and either add it somewhere in your include path, or reference it directly:
#!/bin/bash
dir=''
if [ "$1" != "" ]; then
dir="$1/"
fi
echo "*" > $dir.gitignore && \
echo '!.gitignore' >> $dir.gitignore && \
git add $dir.gitignore
With this, you can either execute it from within the directory you wish to add, or reference the directory as it's first and only parameter:
$ ignore_dir ./some/directory
Another option (in response to a comment by @GreenAsJade), if you want to track an empty folder that MAY contain tracked files in the future, but will be empty for now, you can ommit the * from the .gitignore file, and check that in. Basically, all the file is saying is "do not ignore me", but otherwise, the directory is empty and tracked.
Your .gitignore file would look like:
!.gitignore
That's it, check that in, and you have an empty, yet tracked, directory that you can track files in at some later time.
The reason I suggest keeping that one line in the file is that it gives the .gitignore purpose. Otherwise, some one down the line may think to remove it. It may help if you place a comment above the line.
How do I replace whitespaces with underscore?
use string's replace method:
"this should be connected".replace(" ", "_")
"this_should_be_disconnected".replace("_", " ")
Cocoa Autolayout: content hugging vs content compression resistance priority
Take a look at this video tutorial about Autolayout, they explain it carefully
Calling a java method from c++ in Android
If it's an object method, you need to pass the object to CallObjectMethod:
jobject result = env->CallObjectMethod(obj, messageMe, jstr);
What you were doing was the equivalent of jstr.messageMe().
Since your is a void method, you should call:
env->CallVoidMethod(obj, messageMe, jstr);
If you want to return a result, you need to change your JNI signature (the ()V means a method of void return type) and also the return type in your Java code.
How do I make this file.sh executable via double click?
you can change the file executable by using chmod like this
chmod 755 file.sh
and use this command for execute
./file.sh
How can I add JAR files to the web-inf/lib folder in Eclipse?
- add the jar to WEB-INF/lib from file structure
- refresh the project, you should see the jar now visible under the WEB-INF/lib folder.
java.util.Date format SSSSSS: if not microseconds what are the last 3 digits?
SSSSSS is microseconds. Let us say the time is 10:30:22 (Seconds 22) and 10:30:22.1 would be 22 seconds and 1/10 of a second . Extending the same logic , 10:32.22.000132 would be 22 seconds and 132/1,000,000 of a second, which is nothing but microseconds.
How to install a specific version of Node on Ubuntu?
Here is a list of available builds for debian: https://github.com/nodesource/distributions/tree/master/deb
For this example, lets assume you want version 14 (LTS at the time of writing)
We can download this script from github, execute it and install the version of node we want. For security reasons it's a good idea to read the script prior to executing it.
curl -sL https://raw.githubusercontent.com/nodesource/distributions/master/deb/setup_14.x | bash
apt-get install -y nodejs # may or may not require sudo based on your setup
I like this approach because it doesn't require extraneous dependencies like nvm to target specific versions
If you are building for a different distro or architecture you can find more builds here https://nodejs.org/dist/
Get current language in CultureInfo
Windows.System.UserProfile.GlobalizationPreferences.Languages[0]
This is the correct way to obtain the currently set system language. System language setting is completely different than culture setting from which you all want to get the language.
For example: User may use "en-GB" language along with "en-US" culture at the same time. Using CurrentCulture and other cultures you will get "en-US", hope you get the difference (that may be innoticable with GB-US, but with other languages?)
How are people unit testing with Entity Framework 6, should you bother?
Effort Experience Feedback here
After a lot of reading I have been using Effort in my tests: during the tests the Context is built by a factory that returns a in memory version, which lets me test against a blank slate each time. Outside of the tests, the factory is resolved to one that returns the whole Context.
However i have a feeling that testing against a full featured mock of the database tends to drag the tests down; you realize you have to take care of setting up a whole bunch of dependencies in order to test one part of the system. You also tend to drift towards organizing together tests that may not be related, just because there is only one huge object that handles everything. If you don't pay attention, you may find yourself doing integration testing instead of unit testing
I would have prefered testing against something more abstract rather than a huge DBContext but i couldn't find the sweet spot between meaningful tests and bare-bone tests. Chalk it up to my inexperience.
So i find Effort interesting; if you need to hit the ground running it is a good tool to quickly get started and get results. However i think that something a bit more elegant and abstract should be the next step and that is what I am going to investigate next. Favoriting this post to see where it goes next :)
Edit to add: Effort do take some time to warm up, so you're looking at approx. 5 seconds at test start up. This may be a problem for you if you need your test suite to be very efficient.
Edited for clarification:
I used Effort to test a webservice app. Each message M that enters is routed to a IHandlerOf<M> via Windsor. Castle.Windsor resolves the IHandlerOf<M> which resovles the dependencies of the component. One of these dependencies is the DataContextFactory, which lets the handler ask for the factory
In my tests I instantiate the IHandlerOf component directly, mock all the sub-components of the SUT and handles the Effort-wrapped DataContextFactory to the handler.
It means that I don't unit test in a strict sense, since the DB is hit by my tests. However as I said above it let me hit the ground running and I could quickly test some points in the application
How do I assign ls to an array in Linux Bash?
This would print the files in those directories line by line.
array=(ww/* ee/* qq/*)
printf "%s\n" "${array[@]}"
How to change icon on Google map marker
Manish, Eden after your suggestion: here is the code. But still showing the red(Default) icon.
<script type="text/javascript" src="http://maps.googleapis.com/maps/api/js?sensor=false"></script>
<script type="text/javascript">
var markers = [
{
"title": 'This is title',
"lat": '-37.801578',
"lng": '145.060508',
"icon": 'http://maps.gstatic.com/mapfiles/ridefinder-images/mm_20_green.png',
"description": 'Vikash Rathee. <br/><a href="http://www.pricingindia.in/pincode.aspx">Pin Code by City</a>'
}
];
</script>
<script type="text/javascript">
window.onload = function () {
var mapOptions = {
center: new google.maps.LatLng(markers[0].lat, markers[0].lng),
zoom: 10,
flat: true,
styles: [ { "stylers": [ { "hue": "#4bd6bf" }, { "gamma": "1.58" } ] } ],
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var infoWindow = new google.maps.InfoWindow();
var map = new google.maps.Map(document.getElementById("dvMap"), mapOptions);
for (i = 0; i < markers.length; i++) {
var data = markers[i]
var myLatlng = new google.maps.LatLng(data.lat, data.lng);
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
icon: markers[i][3],
title: data.title
});
(function (marker, data) {
google.maps.event.addListener(marker, "click", function (e) {
infoWindow.setContent(data.description);
infoWindow.open(map, marker);
});
})(marker, data);
}
}
</script>
<div id="dvMap" style="width: 100%; height: 100%">
</div>
How to link an image and target a new window
To open in a new tab use:
target = "_blank"
To open in the same tab use:
target = "_self"
How to read a file into a variable in shell?
As Ciro Santilli notes using command substitutions will drop trailing newlines. Their workaround adding trailing characters is great, but after using it for quite some time I decided I needed a solution that didn't use command substitution at all.
My approach now uses read along with the printf builtin's -v flag in order to read the contents of stdin directly into a variable.
# Reads stdin into a variable, accounting for trailing newlines. Avoids
# needing a subshell or command substitution.
# Note that NUL bytes are still unsupported, as Bash variables don't allow NULs.
# See https://stackoverflow.com/a/22607352/113632
read_input() {
# Use unusual variable names to avoid colliding with a variable name
# the user might pass in (notably "contents")
: "${1:?Must provide a variable to read into}"
if [[ "$1" == '_line' || "$1" == '_contents' ]]; then
echo "Cannot store contents to $1, use a different name." >&2
return 1
fi
local _line _contents=()
while IFS='' read -r _line; do
_contents+=("$_line"$'\n')
done
# include $_line once more to capture any content after the last newline
printf -v "$1" '%s' "${_contents[@]}" "$_line"
}
This supports inputs with or without trailing newlines.
Example usage:
$ read_input file_contents < /tmp/file
# $file_contents now contains the contents of /tmp/file
How to deploy a war file in Tomcat 7
This has been working for me:
- Create your war file (mysite.war) locally.
- Rename it locally to something besides .war, like mysite.www
- With tomcat still running, upload mysite.www to webapps directory.
- After it finishes uploading, delete the previous version mysite.war
- List the directory, watching for the directory /mysite to disappear.
- Rename mysite.www to be mysite.war
- List the directory, watching for the new /mysite to be created.
If you try uploading the new file as a war file, with tomcat still running, it will attempt to expand it before it is all there. It will fail. Having failed, it will not try again. Thus, uploading a www file, then renaming it, allows the whole war file to be present before tomcat notices it.
Hint, don't forget to check that the war file's owner is tomcat (Use chown)
Can I simultaneously declare and assign a variable in VBA?
in fact, you can, but not that way.
Sub MySub( Optional Byval Counter as Long=1 , Optional Byval Events as Boolean= True)
'code...
End Sub
And you can set the variables differently when calling the sub, or let them at their default values.
How eliminate the tab space in the column in SQL Server 2008
Try this code
SELECT REPLACE([Column], char(9), '') From [dbo.Table]
char(9) is the TAB character
Content Security Policy: The page's settings blocked the loading of a resource
I managed to allow all my requisite sites with this header:
header("Content-Security-Policy: default-src *; style-src 'self' 'unsafe-inline'; font-src 'self' data:; script-src 'self' 'unsafe-inline' 'unsafe-eval' stackexchange.com");
How to split a string into an array in Bash?
Sometimes it happened to me that the method described in the accepted answer didn't work, especially if the separator is a carriage return.
In those cases I solved in this way:
string='first line
second line
third line'
oldIFS="$IFS"
IFS='
'
IFS=${IFS:0:1} # this is useful to format your code with tabs
lines=( $string )
IFS="$oldIFS"
for line in "${lines[@]}"
do
echo "--> $line"
done
What is the difference between null=True and blank=True in Django?
null=True sets NULL (versus NOT NULL) on the column in your DB. Blank values for Django field types such as DateTimeField or ForeignKey will be stored as NULL in the DB.
blank determines whether the field will be required in forms. This includes the admin and your custom forms. If blank=True then the field will not be required, whereas if it's False the field cannot be blank.
The combo of the two is so frequent because typically if you're going to allow a field to be blank in your form, you're going to also need your database to allow NULL values for that field. The exception is CharFields and TextFields, which in Django are never saved as NULL. Blank values are stored in the DB as an empty string ('').
A few examples:
models.DateTimeField(blank=True) # raises IntegrityError if blank
models.DateTimeField(null=True) # NULL allowed, but must be filled out in a form
Obviously, Those two options don't make logical sense to use (though there might be a use case for null=True, blank=False if you want a field to always be required in forms, optional when dealing with an object through something like the shell.)
models.CharField(blank=True) # No problem, blank is stored as ''
models.CharField(null=True) # NULL allowed, but will never be set as NULL
CHAR and TEXT types are never saved as NULL by Django, so null=True is unnecessary. However, you can manually set one of these fields to None to force set it as NULL. If you have a scenario where that might be necessary, you should still include null=True.
APT command line interface-like yes/no input?
How about this:
def yes(prompt = 'Please enter Yes/No: '):
while True:
try:
i = raw_input(prompt)
except KeyboardInterrupt:
return False
if i.lower() in ('yes','y'): return True
elif i.lower() in ('no','n'): return False
Split a string by another string in C#
There is an overload of Split that takes strings.
"THExxQUICKxxBROWNxxFOX".Split(new [] { "xx" }, StringSplitOptions.None);
You can use either of these StringSplitOptions
- None - The return value includes array elements that contain an empty string
- RemoveEmptyEntries - The return value does not include array elements that contain an empty string
So if the string is "THExxQUICKxxxxBROWNxxFOX", StringSplitOptions.None will return an empty entry in the array for the "xxxx" part while StringSplitOptions.RemoveEmptyEntries will not.
Find all matches in workbook using Excel VBA
Function GetSearchArray(strSearch)
Dim strResults As String
Dim SHT As Worksheet
Dim rFND As Range
Dim sFirstAddress
For Each SHT In ThisWorkbook.Worksheets
Set rFND = Nothing
With SHT.UsedRange
Set rFND = .Cells.Find(What:=strSearch, LookIn:=xlValues, LookAt:=xlPart, SearchOrder:=xlRows, SearchDirection:=xlNext, MatchCase:=False)
If Not rFND Is Nothing Then
sFirstAddress = rFND.Address
Do
If strResults = vbNullString Then
strResults = "Worksheet(" & SHT.Index & ").Range(" & Chr(34) & rFND.Address & Chr(34) & ")"
Else
strResults = strResults & "|" & "Worksheet(" & SHT.Index & ").Range(" & Chr(34) & rFND.Address & Chr(34) & ")"
End If
Set rFND = .FindNext(rFND)
Loop While Not rFND Is Nothing And rFND.Address <> sFirstAddress
End If
End With
Next
If strResults = vbNullString Then
GetSearchArray = Null
ElseIf InStr(1, strResults, "|", 1) = 0 Then
GetSearchArray = Array(strResults)
Else
GetSearchArray = Split(strResults, "|")
End If
End Function
Sub test2()
For Each X In GetSearchArray("1")
Debug.Print X
Next
End Sub
Careful when doing a Find Loop that you don't get yourself into an infinite loop... Reference the first found cell address and compare after each "FindNext" statement to make sure it hasn't returned back to the first initially found cell.
What is the difference between `throw new Error` and `throw someObject`?
The Error constructor is used to create an error object. Error objects are thrown when runtime errors occur. The Error object can also be used as a base object for user-defined exceptions.
User-defined Errors are thrown via the throw statement. program control will be passed to the first catch block in the call stack.
The difference between throwing an error with and without Error object:
throw {'hehe':'haha'};
In chrome devtools looks like this:
Chrome tells us that we have an uncaught error which just is a JS object. The object itself could have information regarding the error but we still don't know immediately where it came from. Not very useful when we are working on our code and debugging it.
throw new Error({'hehe':'haha'});
In chrome devtools looks like this:
An error thrown with the Error object gives us a stack trace when we expand it. This gives us valuable information where the error precisely came from which is often valuable information when debugging your code. Further note that the error says [object Object], this is because the Error constructor expects a message string as a first argument. When it receives a object it will coerce it into a string.
How to get a list of sub-folders and their files, ordered by folder-names
In command prompt go to the main directory you want the list for ... and type the command tree /f
Xcode 5 and iOS 7: Architecture and Valid architectures
When you set 64-bit the resulting binary is a "Fat" binary, which contains all three Mach-O images bundled with a thin fat header. You can see that using otool or jtool. You can check out some fat binaries included as part of the iOS 7.0 SDK, for example the AVFoundation Framework, like so:
% cd /Developer/Platforms/iPhoneOS.platform/DeviceSupport/7.0\ \(11A465\)/Symbols/System/Library/Frameworks/AVFoundation.framework/
%otool -V -f AVFoundation 9:36
Fat headers
fat_magic FAT_MAGIC
nfat_arch 3
architecture arm64 # The 64-bit version (A7)
cputype CPU_TYPE_ARM64
cpusubtype CPU_SUBTYPE_ARM64_ALL
capabilities 0x0
offset 16384
size 2329888
align 2^14 (16384)
architecture armv7 # A5X - packaged after the arm64version
cputype CPU_TYPE_ARM
cpusubtype CPU_SUBTYPE_ARM_V7
capabilities 0x0
offset 2359296
size 2046336
align 2^14 (16384)
architecture armv7s # A6 - packaged after the armv7 version
cputype CPU_TYPE_ARM
cpusubtype CPU_SUBTYPE_ARM_V7S
capabilities 0x0
offset 4407296
size 2046176
align 2^14 (16384)
As for the binary itself, it uses the ARM64 bit instruction set, which is (mostly compatible with 32-bit, but) a totally different instruction set. This is especially important for graphics program (using NEON instructions and registers). Likewise, the CPU has more registers, which makes quite an impact on program speed. There's an interesting discussion in http://blogs.barrons.com/techtraderdaily/2013/09/19/apple-the-64-bit-question/?mod=yahoobarrons on whether or not this makes a difference; benchmarking tests have so far clearly indicated that it does.
Using otool -tV will dump the assembly (if you have XCode 5 and later), and then you can see the instruction set differences for yourself. Most (but not all) developers will remain agnostic to the changes, as for the most part they do not directly affect Obj-C (CG* APIs notwithstanding), and have to do more with low level pointer handling. The compiler will work its magic and optimizations.
Check if boolean is true?
i personally would prefer
if(true == foo)
{
}
there is no chance for the ==/= mistype and i find it more expressive in terms of foo's type. But it is a very subjective question.
Language Books/Tutorials for popular languages
For Lisp and Scheme (hell, functional programming in general), there are few things that provide a more solid foundation than The Little Schemer and The Seasoned Schemer. Both provide a very simple and intuitive introduction to both Scheme and functional programming that proves far simpler for new students or hobbyists than any of the typical volumes that rub off like a nonfiction rendition of War & Peace.
Once they've moved beyond the Schemer series, SICP and On Lisp are both fantastic choices.
SVN Repository Search
Update January, 2020
VisualSVN Server 4.2 supports finding files and folders in the web interface. Try out the new feature on one of the demo server’s repositories!
See the version 4.2 Release Notes, and download VisualSVN Server 4.2.0 from the main download page.
Old answer
Beginning with Subversion 1.8, you can use --search option with svn log command. Note that the command does not perform full-text search inside a repository, it considers the following data only:
- revision's author (
svn:authorunversioned property), - date (
svn:dateunversioned property), - log message text (
svn:logunversioned property), - list of changed paths (i.e. paths affected by the particular revision).
Here is the help page about these new search options:
If the --search option is used, log messages are displayed only if the
provided search pattern matches any of the author, date, log message
text (unless --quiet is used), or, if the --verbose option is also
provided, a changed path.
The search pattern may include "glob syntax" wildcards:
? matches any single character
* matches a sequence of arbitrary characters
[abc] matches any of the characters listed inside the brackets
If multiple --search options are provided, a log message is shown if
it matches any of the provided search patterns. If the --search-and
option is used, that option's argument is combined with the pattern
from the previous --search or --search-and option, and a log message
is shown only if it matches the combined search pattern.
If --limit is used in combination with --search, --limit restricts the
number of log messages searched, rather than restricting the output
to a particular number of matching log messages.
Using :after to clear floating elements
This will work as well:
.clearfix:before,
.clearfix:after {
content: "";
display: table;
}
.clearfix:after {
clear: both;
}
/* IE 6 & 7 */
.clearfix {
zoom: 1;
}
Give the class clearfix to the parent element, for example your ul element.
How to Set focus to first text input in a bootstrap modal after shown
this is the most general solution
$('body').on('shown.bs.modal', '.modal', function () {
$(this).find(":input:not(:button):visible:enabled:not([readonly]):first").focus();
});
- works with modals added to DOM after page load
- works with input, textarea, select and not with button
- ommits hidden, disabled, readonly
- works with faded modals, no need for setInterval
Multiple Order By with LINQ
You can use the ThenBy and ThenByDescending extension methods:
foobarList.OrderBy(x => x.Foo).ThenBy( x => x.Bar)
Can I set the cookies to be used by a WKWebView?
This is my solution to handle with Cookies and WKWebView in iOS 9 or later.
import WebKit
extension WebView {
enum LayoutMode {
case fillContainer
}
func autoLayout(_ view: UIView?, mode: WebView.LayoutMode = .fillContainer) {
guard let view = view else { return }
self.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(self)
switch mode {
case .fillContainer:
NSLayoutConstraint.activate([
self.topAnchor.constraint(equalTo: view.topAnchor),
self.leadingAnchor.constraint(equalTo: view.leadingAnchor),
self.trailingAnchor.constraint(equalTo: view.trailingAnchor),
self.bottomAnchor.constraint(equalTo: view.bottomAnchor)
])
}
}
}
class WebView : WKWebView {
var request : URLRequest?
func load(url: URL, useSharedCookies: Bool = false) {
if useSharedCookies, let cookies = HTTPCookieStorage.shared.cookies(for: url) {
self.load(url: url, withCookies: cookies)
} else {
self.load(URLRequest(url: url))
}
}
func load(url: URL, withCookies cookies: [HTTPCookie]) {
self.request = URLRequest(url: url)
let headers = HTTPCookie.requestHeaderFields(with: cookies)
self.request?.allHTTPHeaderFields = headers
self.load(request!)
}
}
JAX-WS client : what's the correct path to access the local WSDL?
The best option is to use jax-ws-catalog.xml
When you compile the local WSDL file , override the WSDL location and set it to something like
http://localhost/wsdl/SOAService.wsdl
Don't worry this is only a URI and not a URL , meaning you don't have to have the WSDL available at that address.
You can do this by passing the wsdllocation option to the wsdl to java compiler.
Doing so will change your proxy code from
static {
URL url = null;
try {
URL baseUrl;
baseUrl = com.ibm.eci.soaservice.SOAService.class.getResource(".");
url = new URL(baseUrl, "file:/C:/local/path/to/wsdl/SOAService.wsdl");
} catch (MalformedURLException e) {
logger.warning("Failed to create URL for the wsdl Location: 'file:/C:/local/path/to/wsdl/SOAService.wsdl', retrying as a local file");
logger.warning(e.getMessage());
}
SOASERVICE_WSDL_LOCATION = url;
}
to
static {
URL url = null;
try {
URL baseUrl;
baseUrl = com.ibm.eci.soaservice.SOAService.class.getResource(".");
url = new URL(baseUrl, "http://localhost/wsdl/SOAService.wsdl");
} catch (MalformedURLException e) {
logger.warning("Failed to create URL for the wsdl Location: 'http://localhost/wsdl/SOAService.wsdl', retrying as a local file");
logger.warning(e.getMessage());
}
SOASERVICE_WSDL_LOCATION = url;
}
Notice file:// changed to http:// in the URL constructor.
Now comes in jax-ws-catalog.xml. Without jax-ws-catalog.xml jax-ws will indeed try to load the WSDL from the location
http://localhost/wsdl/SOAService.wsdland fail, as no such WSDL will be available.
But with jax-ws-catalog.xml you can redirect jax-ws to a locally packaged WSDL whenever it tries to access the WSDL @
http://localhost/wsdl/SOAService.wsdl.
Here's jax-ws-catalog.xml
<catalog xmlns="urn:oasis:names:tc:entity:xmlns:xml:catalog" prefer="system">
<system systemId="http://localhost/wsdl/SOAService.wsdl"
uri="wsdl/SOAService.wsdl"/>
</catalog>
What you are doing is telling jax-ws that when ever it needs to load WSDL from
http://localhost/wsdl/SOAService.wsdl, it should load it from local path wsdl/SOAService.wsdl.
Now where should you put wsdl/SOAService.wsdl and jax-ws-catalog.xml ? That's the million dollar question isn't it ?
It should be in the META-INF directory of your application jar.
so something like this
ABCD.jar
|__ META-INF
|__ jax-ws-catalog.xml
|__ wsdl
|__ SOAService.wsdl
This way you don't even have to override the URL in your client that access the proxy. The WSDL is picked up from within your JAR, and you avoid having to have hard-coded filesystem paths in your code.
More info on jax-ws-catalog.xml http://jax-ws.java.net/nonav/2.1.2m1/docs/catalog-support.html
Hope that helps
Are 64 bit programs bigger and faster than 32 bit versions?
Any applications that require CPU usage such as transcoding, display performance and media rendering, whether it be audio or visual, will certainly require (at this point) and benefit from using 64 bit versus 32 bit due to the CPU's ability to deal with the sheer amount of data being thrown at it. It's not so much a question of address space as it is the way the data is being dealt with. A 64 bit processor, given 64 bit code, is going to perform better, especially with mathematically difficult things like transcoding and VoIP data - in fact, any sort of 'math' applications should benefit by the usage of 64 bit CPUs and operating systems. Prove me wrong.
Are PostgreSQL column names case-sensitive?
The column names which are mixed case or uppercase have to be double quoted in PostgresQL. So best convention will be to follow all small case with underscore.
Output ("echo") a variable to a text file
Your sample code seems to be OK. Thus, the root problem needs to be dug up somehow. Let's eliminate chance for typos in the script. First off, make sure you put Set-Strictmode -Version 2.0 in the beginning of your script. This will help you to catch misspelled variable names. Like so,
# Test.ps1
set-strictmode -version 2.0 # Comment this line and no error will be reported.
$foo = "bar"
set-content -path ./test.txt -value $fo # Error! Should be "$foo"
PS C:\temp> .\test.ps1
The variable '$fo' cannot be retrieved because it has not been set.
At C:\temp\test.ps1:3 char:40
+ set-content -path ./test.txt -value $fo <<<<
+ CategoryInfo : InvalidOperation: (fo:Token) [], RuntimeException
+ FullyQualifiedErrorId : VariableIsUndefined
The next part about question marks sounds like you have a problem with Unicode. What's the output when you type the file with Powershell like so,
$file = "\\server\share\file.txt"
cat $file
How to test an Internet connection with bash?
Similarly to @Jesse's answer, this option might be much faster than any solution using ping and perhaps slightly more efficient than @Jesse's answer.
find /sys/class/net/ -maxdepth 1 -mindepth 1 ! -name "*lo*" -exec sh -c 'cat "$0"/carrier 2>&1' {} \; | grep -q '1'
Explenation:
This command uses find with -exec to run command on all files not named *lo* in /sys/class/net/. These should be links to directories containing information about the available network interfaces on your machine.
The command being ran is an sh command that checks the contents of the file carrier in those directories. The value of $interface/carrier has 3 meanings - Quoting:
It seems there are three states:
- ./carrier not readable (for instance when the interface is disabled in Network Manager).
- ./carrier contain "1" (when the interface is activated and it is connected to a WiFi network)
- ./carrier contain "0" (when the interface is activated and it is not connected to a WiFi network)
The first option is not taken care of in @Jesse's answer. The sh command striped out is:
# Note: $0 == $interface
cat "$0"/carrier 2>&1
cat is being used to check the contents of carrier and redirect all output to standard output even when it fails because the file is not readable.
If grep -q finds "1" among those files it means there is at least 1 interface connected. The exit code of grep -q will be the final exit code.
Usage
For example, using this command's exit status, you can use it start a gnubiff in your ~/.xprofile only if you have an internet connection.
online() {
find /sys/class/net/ -maxdepth 1 -mindepth 1 ! -name "*lo*" -exec sh -c 'cat "$0"/carrier 2>&1 > /dev/null | grep -q "1" && exit 0' {} \;
}
online && gnubiff --systemtray --noconfigure &
Reference
Second line in li starts under the bullet after CSS-reset
Here is a good example -
ul li{
list-style-type: disc;
list-style-position: inside;
padding: 10px 0 10px 20px;
text-indent: -1em;
}
Working Demo: http://jsfiddle.net/d9VNk/
What is the best way to programmatically detect porn images?
This is a nudity detector. I haven't tried it. It's the only OSS one I could find.
Is there a JavaScript / jQuery DOM change listener?
For a long time, DOM3 mutation events were the best available solution, but they have been deprecated for performance reasons. DOM4 Mutation Observers are the replacement for deprecated DOM3 mutation events. They are currently implemented in modern browsers as MutationObserver (or as the vendor-prefixed WebKitMutationObserver in old versions of Chrome):
MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
var observer = new MutationObserver(function(mutations, observer) {
// fired when a mutation occurs
console.log(mutations, observer);
// ...
});
// define what element should be observed by the observer
// and what types of mutations trigger the callback
observer.observe(document, {
subtree: true,
attributes: true
//...
});
This example listens for DOM changes on document and its entire subtree, and it will fire on changes to element attributes as well as structural changes. The draft spec has a full list of valid mutation listener properties:
childList
- Set to
trueif mutations to target's children are to be observed.attributes
- Set to
trueif mutations to target's attributes are to be observed.characterData
- Set to
trueif mutations to target's data are to be observed.subtree
- Set to
trueif mutations to not just target, but also target's descendants are to be observed.attributeOldValue
- Set to
trueifattributesis set to true and target's attribute value before the mutation needs to be recorded.characterDataOldValue
- Set to
trueifcharacterDatais set to true and target's data before the mutation needs to be recorded.attributeFilter
- Set to a list of attribute local names (without namespace) if not all attribute mutations need to be observed.
(This list is current as of April 2014; you may check the specification for any changes.)
Kubernetes pod gets recreated when deleted
In some cases the pods will still not go away even when deleting the deployment. In that case to force delete them you can run the below command.
kubectl delete pods podname --grace-period=0 --force
How to highlight a selected row in ngRepeat?
Each row has an ID. All you have to do is to send this ID to the function setSelected(), store it (in $scope.idSelectedVote for instance), and then check for each row if the selected ID is the same as the current one. Here is a solution (see the documentation for ngClass, if needed):
$scope.idSelectedVote = null;
$scope.setSelected = function (idSelectedVote) {
$scope.idSelectedVote = idSelectedVote;
};
<ul ng-repeat="vote in votes" ng-click="setSelected(vote.id)" ng-class="{selected: vote.id === idSelectedVote}">
...
</ul>
Can't create handler inside thread that has not called Looper.prepare()
I was getting this error until I did the following.
public void somethingHappened(final Context context)
{
Handler handler = new Handler(Looper.getMainLooper());
handler.post(
new Runnable()
{
@Override
public void run()
{
Toast.makeText(context, "Something happened.", Toast.LENGTH_SHORT).show();
}
}
);
}
And made this into a singleton class:
public enum Toaster {
INSTANCE;
private final Handler handler = new Handler(Looper.getMainLooper());
public void postMessage(final String message) {
handler.post(
new Runnable() {
@Override
public void run() {
Toast.makeText(ApplicationHolder.INSTANCE.getCustomApplication(), message, Toast.LENGTH_SHORT)
.show();
}
}
);
}
}
java.io.IOException: Could not locate executable null\bin\winutils.exe in the Hadoop binaries. spark Eclipse on windows 7
Follow this:
Create a
binfolder in any directory(to be used in step 3).Download winutils.exe and place it in the bin directory.
Now add
System.setProperty("hadoop.home.dir", "PATH/TO/THE/DIR");in your code.
Styling the arrow on bootstrap tooltips
You can use this to change tooltip-arrow color
.tooltip.bottom .tooltip-arrow {
top: 0;
left: 50%;
margin-left: -5px;
border-bottom-color: #000000; /* black */
border-width: 0 5px 5px;
}
Is there a Google Sheets formula to put the name of the sheet into a cell?
Here is what I found for Google Sheets:
To get the current sheet name in Google sheets, the following simple script can help you without entering the name manually, please do as this:
Click Tools > Script editor
In the opened project window, copy and paste the below script code into the blank Code window, see screenshot:
......................
function sheetName() {
return SpreadsheetApp.getActiveSpreadsheet().getActiveSheet().getName();
}
Then save the code window, and go back to the sheet that you want to get its name, then enter this formula: =sheetName() in a cell, and press Enter key, the sheet name will be displayed at once.
See this link with added screenshots: https://www.extendoffice.com/documents/excel/5222-google-sheets-get-list-of-sheets.html
Checking if a variable is initialized
With C++-11 or Boost libs you could consider storing the variable using smart pointers. Consider this MVE where toString() behaviour depends on bar being initialized or not:
#include <memory>
#include <sstream>
class Foo {
private:
std::shared_ptr<int> bar;
public:
Foo() {}
void setBar(int bar) {
this->bar = std::make_shared<int>(bar);
}
std::string toString() const {
std::ostringstream ss;
if (bar) // bar was set
ss << *bar;
else // bar was never set
ss << "unset";
return ss.str();
}
};
Using this code
Foo f;
std::cout << f.toString() << std::endl;
f.setBar(42);
std::cout << f.toString() << std::endl;
produces the output
unset
42
Can I write native iPhone apps using Python?
You can use PyObjC on the iPhone as well, due to the excellent work by Jay Freeman (saurik). See iPhone Applications in Python.
Note that this requires a jailbroken iPhone at the moment.
How do I create a transparent Activity on Android?
I achieved it on 2.3.3 by just adding android:theme="@android:style/Theme.Translucent" in the activity tag in the manifest.
I don't know about lower versions...
Node.js: How to send headers with form data using request module?
This should work.
var url = 'http://<your_url_here>';
var headers = {
'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:24.0) Gecko/20100101 Firefox/24.0',
'Content-Type' : 'application/x-www-form-urlencoded'
};
var form = { username: 'user', password: '', opaque: 'someValue', logintype: '1'};
request.post({ url: url, form: form, headers: headers }, function (e, r, body) {
// your callback body
});
Viewing full output of PS command
I found this answer which is what nailed it for me as none of the above answers worked
https://unix.stackexchange.com/questions/91561/ps-full-command-is-too-long
Basically, the kernel is limiting my cmd line.
How to completely remove borders from HTML table
This is what resolved the problem for me:
In your HTML tr tag, add this:
style="border-collapse: collapse; border: none;"
That removed all the borders that were showing on the table row.
Can't install laravel installer via composer
It says that it requires zip extension
laravel/installer v1.4.0 requires ext-zip...
Install using (to install the default version):
sudo apt install php-zip
Or, if you're running a specific version of PHP:
# For php v7.0
sudo apt-get install php7.0-zip
# For php v7.1
sudo apt-get install php7.1-zip
# For php v7.2
sudo apt-get install php7.2-zip
# For php v7.3
sudo apt-get install php7.3-zip
# For php v7.4
sudo apt-get install php7.4-zip
A Java collection of value pairs? (tuples?)
I was going to ask if you would not want to just use a List<Pair<T, U>>? but then, of course, the JDK doesn't have a Pair<> class. But a quick Google found one on both Wikipedia, and forums.sun.com. Cheers
How to get value in the session in jQuery
Sessions are stored on the server and are set from server side code, not client side code such as JavaScript.
What you want is a cookie, someone's given a brilliant explanation in this Stack Overflow question here: How do I set/unset cookie with jQuery?
You could potentially use sessions and set/retrieve them with jQuery and AJAX, but it's complete overkill if Cookies will do the trick.
How to create a hidden <img> in JavaScript?
Try setting the style to display=none:
<img src="a.gif" style="display:none">
How can I get the values of data attributes in JavaScript code?
You can access it as
element.dataset.points
etc. So in this case: this.dataset.points
How to create a toggle button in Bootstrap
Bootstrap 4 solution
bootstrap 4 ships built-in toggle. Here is the documentation. https://getbootstrap.com/docs/4.3/components/forms/#switches
How to plot a 2D FFT in Matlab?
Assuming that I is your input image and F is its Fourier Transform (i.e. F = fft2(I))
You can use this code:
F = fftshift(F); % Center FFT
F = abs(F); % Get the magnitude
F = log(F+1); % Use log, for perceptual scaling, and +1 since log(0) is undefined
F = mat2gray(F); % Use mat2gray to scale the image between 0 and 1
imshow(F,[]); % Display the result
Why does ++[[]][+[]]+[+[]] return the string "10"?
Step by steps of that, + turn value to a number and if you add to an empty array +[]...as it's empty and is equal to 0, it will
So from there, now look into your code, it's ++[[]][+[]]+[+[]]...
And there is plus between them ++[[]][+[]] + [+[]]
So these [+[]] will return [0] as they have an empty array which gets converted to 0 inside the other array...
So as imagine, the first value is a 2-dimensional array with one array inside... so [[]][+[]] will be equal to [[]][0] which will return []...
And at the end ++ convert it and increase it to 1...
So you can imagine, 1 + "0" will be "10"...
Is there a way to use use text as the background with CSS?
I hope this might help you
<!DOCTYPE html>
<html>
<head>
<style>
:root:after {
content: "Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark Watermark ";
position: fixed;
transform: rotate(300deg);
-webkit-transform: rotate(300deg);
color: rgb(187, 182, 182);
top:0;
z-index: -1;
}
</style>
</head>
<body>
<p>hey my name is JHM</p>
</body>
</html>How to run a single RSpec test?
You can pass a regex to the spec command which will only run it blocks matching the name you supply.
spec path/to/my_spec.rb -e "should be the correct answer"
2019 Update: Rspec2 switched from the 'spec' command to the 'rspec' command.
How do I create a folder in a GitHub repository?
Click on new file in github repo online.
Then write file name as myfolder/myfilename then give file contents and commit. Then file will be created within that new folder.
Printing PDFs from Windows Command Line
Here is another solution:
1) Download SumatraPDF (portable version) - https://www.sumatrapdfreader.org/download-free-pdf-viewer.html
2) Create a class library project and unzip the SumatraPDF.exe to the project directory root and unblock it.
3) Inside the project Properties, go to the Resoruces tab and add the exe as a file.
4) Add the following class to your library:
public class SumatraWrapper : IDisposable
{
private readonly FileInfo _tempFileForExe = null;
private readonly FileInfo _exe = null;
public SumatraWrapper()
{
_exe = ExtractExe();
}
public SumatraWrapper(FileInfo tempFileForExe)
: this()
{
_tempFileForExe = tempFileForExe ?? throw new ArgumentNullException(nameof(tempFileForExe));
}
private FileInfo ExtractExe()
{
string tempfile =
_tempFileForExe != null ?
_tempFileForExe.FullName :
Path.GetTempFileName() + ".exe";
FileInfo exe = new FileInfo(tempfile);
byte[] bytes = Properties.Resources.SumatraPDF;
using (FileStream fs = exe.OpenWrite())
{
fs.Write(bytes, 0, bytes.Length);
}
return exe;
}
public bool Print(FileInfo file, string printerName)
{
string arguments = $"-print-to \"{printerName}\" \"{file.FullName}\"";
ProcessStartInfo processStartInfo = new ProcessStartInfo(_exe.FullName, arguments)
{
CreateNoWindow = true
};
using (Process process = Process.Start(processStartInfo))
{
process.WaitForExit();
return process.ExitCode == 0;
}
}
#region IDisposable Support
private bool disposedValue = false; // To detect redundant calls
protected virtual void Dispose(bool disposing)
{
if (!disposedValue)
{
if (disposing)
{
// TODO: dispose managed state (managed objects).
}
// TODO: free unmanaged resources (unmanaged objects) and override a finalizer below.
// TODO: set large fields to null.
try
{
File.Delete(_exe.FullName);
}
catch
{
}
disposedValue = true;
}
}
// TODO: override a finalizer only if Dispose(bool disposing) above has code to free unmanaged resources.
// ~PdfToPrinterWrapper() {
// // Do not change this code. Put cleanup code in Dispose(bool disposing) above.
// Dispose(false);
// }
// This code added to correctly implement the disposable pattern.
public void Dispose()
{
// Do not change this code. Put cleanup code in Dispose(bool disposing) above.
Dispose(true);
// TODO: uncomment the following line if the finalizer is overridden above.
// GC.SuppressFinalize(this);
}
#endregion
}
5) Enjoy printing pdf files from your code.
Use like this:
FileInfo file = new FileInfo(@"c:\Sandbox\dummy file.pdf");
SumatraWrapper pdfToPrinter =
new SumatraWrapper();
pdfToPrinter.Print(file, "My Printer");
Postgres "psql not recognized as an internal or external command"
Windows 10
It could be that your server doesn't start automatically on windows 10 and you need to start it yourself after setting your Postgresql path using the following command in cmd:
pg_ctl -D "C:\Program Files\PostgreSQL\11.4\data" start
You need to be inside "C:\Program Files\PostgreSQL\11.4\bin" directory to execute the above command.
EX:
You still need to be inside the bin directory to work with psql
Why can't Python find shared objects that are in directories in sys.path?
Had the exact same issue. I installed curl 7.19 to /opt/curl/ to make sure that I would not affect current curl on our production servers. Once I linked libcurl.so.4 to /usr/lib:
sudo ln -s /opt/curl/lib/libcurl.so /usr/lib/libcurl.so.4
I still got the same error! Durf.
But running ldconfig make the linkage for me and that worked. No need to set the LD_RUN_PATH or LD_LIBRARY_PATH at all. Just needed to run ldconfig.
^[A-Za-Z ][A-Za-z0-9 ]* regular expression?
This expression will force the first letter to be alphabetic and the remaining characters to be alphanumeric or any of the following special characters: @,#,%,&,*
^[A-Za-z][A-Za-z0-9@#%&*]*$
Cannot obtain value of local or argument as it is not available at this instruction pointer, possibly because it has been optimized away
Regarding the problem with "Optimize code" property being UNCHECKED yet the code still compiling as optimized: What finally helped me after trying everything was checking the "Enable unmanaged code debugging" checkbox on the same settings page (Project properties - Debug). It doesn't directly relate to the code optimization, but with this enabled, VS no longer optimizes my library and I can debug.
Java error - "invalid method declaration; return type required"
You forgot to declare double as a return type
public double diameter()
{
double d = radius * 2;
return d;
}
Replace Div with another Div
This should help you
HTML
<!-- pretty much i just need to click a link within the regions table and it changes to the neccesary div. -->
<table>
<tr class="thumb"></tr>
<td><a href="#" class="showall">All Regions</a> (shows main map) (link)</td>
<tr class="thumb"></tr>
<td>Northern Region (link)</td>
</tr>
<tr class="thumb"></tr>
<td>Southern Region (link)</td>
</tr>
<tr class="thumb"></tr>
<td>Eastern Region (link)</td>
</tr>
</table>
<br />
<div id="mainmapplace">
<div id="mainmap">
All Regions image
</div>
</div>
<div id="region">
<div class="replace">northern image</div>
<div class="replace">southern image</div>
<div class="replace">Eastern image</div>
</div>
JavaScript
var originalmap;
var flag = false;
$(function (){
$(".replace").click(function(){
flag = true;
originalmap = $('#mainmap');
$('#mainmap').replaceWith($(this));
});
$('.showall').click(
function(){
if(flag == true){
$('#region').append($('#mainmapplace .replace'));
$('#mainmapplace').children().remove();
$('#mainmapplace').append($(originalmap));
//$('#mapplace').append();
}
}
)
})
CSS
#mainmapplace{
width: 100px;
height: 100px;
background: red;
}
#region div{
width: 100px;
height: 100px;
background: blue;
margin: 10px 0 0 0;
}
Setting network adapter metric priority in Windows 7
Windows has two different settings in which priority is established. There is the metric value which you have already set in the adapter settings, and then there is the connection priority in the network connections settings.
To change the priority of the connections:
- Open your Adapter Settings (Control Panel\Network and Internet\Network Connections)
- Click Alt to pull up the menu bar
- Select Advanced -> Advanced Settings
- Change the order of the connections so that the connection you want to have priority is top on the list
Merge DLL into EXE?
Download
Call
ilmerge /target:winexe /out:c:\output.exe c:\input.exe C:\input.dll
How to pass the id of an element that triggers an `onclick` event to the event handling function
I would suggest the use of jquery mate.
With jQuery you would then be able to get the id of this element by
$(this).attr('id');
without jquery, if I remember correctly we used to access the id with a
this.id
Hope that helps :)
How to trigger button click in MVC 4
MVC doesn't do events. Just put a form and submit button on the page and the method decorated with the HttpPost attribute will process that request.
You might want to read a tutorial or two on how to create views, forms and controllers.
Running SSH Agent when starting Git Bash on Windows
I could not get this to work based off the best answer, probably because I'm such a PC noob and missing something obvious. But just FYI in case it helps someone as challenged as me, what has FINALLY worked was through one of the links here (referenced in the answers). This involved simply pasting the following to my .bash_profile:
env=~/.ssh/agent.env
agent_load_env () { test -f "$env" && . "$env" >| /dev/null ; }
agent_start () {
(umask 077; ssh-agent >| "$env")
. "$env" >| /dev/null ; }
agent_load_env
# agent_run_state: 0=agent running w/ key; 1=agent w/o key; 2= agent not running
agent_run_state=$(ssh-add -l >| /dev/null 2>&1; echo $?)
if [ ! "$SSH_AUTH_SOCK" ] || [ $agent_run_state = 2 ]; then
agent_start
ssh-add
elif [ "$SSH_AUTH_SOCK" ] && [ $agent_run_state = 1 ]; then
ssh-add
fi
unset env
I probably have something configured weird, but was not successful when I added it to my .profile or .bashrc. The other real challenge I've run into is I'm not an admin on this computer and can't change the environment variables without getting it approved by IT, so this is a solution for those that can't access that.
You know it's working if you're prompted for your ssh password when you open git bash. Hallelujah something finally worked.
Convert date to UTC using moment.js
here, I'm passing the date object and converting it into UTC time.
$.fn.convertTimeToUTC = function (convertTime) {
if($(this).isObject(convertTime)) {
return moment.tz(convertTime.format("Y-MM-DD HH:mm:ss"), moment.tz.guess()).utc().format("Y-MM-DD HH:mm:ss");
}
};
// Returns if a value is an object
$.fn.isObject = function(value) {
return value && typeof value === 'object';
};
//you can call it as below
$(this).convertTimeToUTC(date);
React Router with optional path parameter
If you are looking to do an exact match, use the following syntax:
(param)?.
Eg.
<Route path={`my/(exact)?/path`} component={MyComponent} />
The nice thing about this is that you'll have props.match to play with, and you don't need to worry about checking the value of the optional parameter:
{ props: { match: { "0": "exact" } } }
How does the modulus operator work?
You can think of the modulus operator as giving you a remainder. count % 6 divides 6 out of count as many times as it can and gives you a remainder from 0 to 5 (These are all the possible remainders because you already divided out 6 as many times as you can). The elements of the array are all printed in the for loop, but every time the remainder is 5 (every 6th element), it outputs a newline character. This gives you 6 elements per line. For 5 elements per line, use
if (count % 5 == 4)
Force LF eol in git repo and working copy
Starting with git 2.10 (released 2016-09-03), it is not necessary to enumerate each text file separately. Git 2.10 fixed the behavior of text=auto together with eol=lf. Source.
.gitattributes file in the root of your git repository:
* text=auto eol=lf
Add and commit it.
Afterwards, you can do following to steps and all files are normalized now:
git rm --cached -r . # Remove every file from git's index.
git reset --hard # Rewrite git's index to pick up all the new line endings.
Source: Answer by kenorb.
PostgreSQL database service
- check conenctionstring
- check SSL
- check firewall
- if u use VS studio, check for db driver
How to style a div to have a background color for the entire width of the content, and not just for the width of the display?
The inline-block display style seems to do what you want. Note that the <nobr> tag is deprecated, and should not be used. Non-breaking white space is doable in CSS. Here's how I would alter your example style rules:
div { display: inline-block; white-space: nowrap; }
.success { background-color: #ccffcc; }
Alter your stylesheet, remove the <nobr> tags from your source, and give it a try. Note that display: inline-block does not work in every browser, though it tends to only be problematic in older browsers (newer versions should support it to some degree). My personal opinion is to ignore coding for broken browsers. If your code is standards compliant, it should work in all of the major, modern browsers. Anyone still using IE6 (or earlier) deserves the pain. :-)
Set cURL to use local virtual hosts
For setting up virtual hosts on Apache http-servers that are not yet connected via DNS, I like to use:
curl -s --connect-to ::host-name: http://project1.loc/post.json
Where host-name ist the IP address or the DNS name of the machine on which the web-server is running. This also works well for https-Sites.
Local file access with JavaScript
NW.js allows you to create desktop applications using Javascript without all the security restrictions usually placed on the browser. So you can run executables with a function, or create/edit/read/write/delete files. You can access the hardware, such as current CPU usage or total ram in use, etc.
You can create a windows, linux, or mac desktop application with it that doesn't require any installation.
How can I break up this long line in Python?
For anyone who is also trying to call .format() on a long string, and is unable to use some of the most popular string wrapping techniques without breaking the subsequent .format( call, you can do str.format("", 1, 2) instead of "".format(1, 2). This lets you break the string with whatever technique you like. For example:
logger.info("Skipping {0} because its thumbnail was already in our system as {1}.".format(line[indexes['url']], video.title))
can be
logger.info(str.format(("Skipping {0} because its thumbnail was already"
+ "in our system as {1}"), line[indexes['url']], video.title))
Otherwise, the only possibility is using line ending continuations, which I personally am not a fan of.
Spark difference between reduceByKey vs groupByKey vs aggregateByKey vs combineByKey
ReduceByKey reduceByKey(func, [numTasks])-
Data is combined so that at each partition there should be at least one value for each key. And then shuffle happens and it is sent over the network to some particular executor for some action such as reduce.
GroupByKey - groupByKey([numTasks])
It doesn't merge the values for the key but directly the shuffle process happens and here lot of data gets sent to each partition, almost same as the initial data.
And the merging of values for each key is done after the shuffle. Here lot of data stored on final worker node so resulting in out of memory issue.
AggregateByKey - aggregateByKey(zeroValue)(seqOp, combOp, [numTasks])
It is similar to reduceByKey but you can provide initial values when performing aggregation.
Use of reduceByKey
reduceByKeycan be used when we run on large data set.reduceByKeywhen the input and output value types are of same type overaggregateByKey
Moreover it recommended not to use groupByKey and prefer reduceByKey. For details you can refer here.
You can also refer this question to understand in more detail how reduceByKey and aggregateByKey.
How to add anything in <head> through jquery/javascript?
Try a javascript pure:
Library JS:
appendHtml = function(element, html) {
var div = document.createElement('div');
div.innerHTML = html;
while (div.children.length > 0) {
element.appendChild(div.children[0]);
}
}
Type:
appendHtml(document.head, '<link rel="stylesheet" type="text/css" href="http://example.com/example.css"/>');
or jQuery:
$('head').append($('<link rel="stylesheet" type="text/css" />').attr('href', 'http://example.com/example.css'));
Cannot authenticate into mongo, "auth fails"
You can also try this :-
mongo localhost:27017/admin -u admin -p SECRETPASSWORD
Found it in this post
Here obviously the localhost can be some other host and the /admin can be some other database on which authentication has been applied
Servlet Mapping using web.xml
It allows servlets to have multiple servlet mappings:
<servlet>
<servlet-name>Servlet1</servlet-name>
<servlet-path>foo.Servlet</servlet-path>
</servlet>
<servlet-mapping>
<servlet-name>Servlet1</servlet-name>
<url-pattern>/enroll</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Servlet1</servlet-name>
<url-pattern>/pay</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>Servlet1</servlet-name>
<url-pattern>/bill</url-pattern>
</servlet-mapping>
It allows filters to be mapped on the particular servlet:
<filter-mapping>
<filter-name>Filter1</filter-name>
<servlet-name>Servlet1</servlet-name>
</filter-mapping>
Your proposal would support neither of them. Note that the web.xml is read and parsed only once during application's startup, not on every HTTP request as you seem to think.
Since Servlet 3.0, there's the @WebServlet annotation which minimizes this boilerplate:
@WebServlet("/enroll")
public class Servlet1 extends HttpServlet {
See also:
Converting Symbols, Accent Letters to English Alphabet
Following Class does the trick:
org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter
ERROR Error: Uncaught (in promise), Cannot match any routes. URL Segment
As the error says your router link should match the existing routes configured
It should be just routerLink="/about"
Efficient evaluation of a function at every cell of a NumPy array
All above answers compares well, but if you need to use custom function for mapping, and you have numpy.ndarray, and you need to retain the shape of array.
I have compare just two, but it will retain the shape of ndarray. I have used the array with 1 million entries for comparison. Here I use square function. I am presenting the general case for n dimensional array. For two dimensional just make iter for 2D.
import numpy, time
def A(e):
return e * e
def timeit():
y = numpy.arange(1000000)
now = time.time()
numpy.array([A(x) for x in y.reshape(-1)]).reshape(y.shape)
print(time.time() - now)
now = time.time()
numpy.fromiter((A(x) for x in y.reshape(-1)), y.dtype).reshape(y.shape)
print(time.time() - now)
now = time.time()
numpy.square(y)
print(time.time() - now)
Output
>>> timeit()
1.162431240081787 # list comprehension and then building numpy array
1.0775556564331055 # from numpy.fromiter
0.002948284149169922 # using inbuilt function
here you can clearly see numpy.fromiter user square function, use any of your choice. If you function is dependent on i, j that is indices of array, iterate on size of array like for ind in range(arr.size), use numpy.unravel_index to get i, j, .. based on your 1D index and shape of array numpy.unravel_index
This answers is inspired by my answer on other question here
Bootstrap 3 - Responsive mp4-video
using that code wil give you a responsive video player with full control
<div class="embed-responsive embed-responsive-16by9">
<iframe class="embed-responsive-item" width="640" height="480" src="https://www.youtube-nocookie.com/embed/Lw_e0vF1IB4" frameborder="0" allowfullscreen></iframe>
</div>
How can I undo a mysql statement that I just executed?
For some instrutions, like ALTER TABLE, this is not possible with MySQL, even with transactions (1 and 2).
Selecting one row from MySQL using mysql_* API
this shoude work
<?php
require_once('connection.php');
//fetch table rows from mysql db
$sql = "select id,fname,lname,sms,phone from data";
$result = mysqli_query($conn, $sql) or die("Error in Selecting " . mysqli_error($conn));
//create an array
$emparray = array();
for ($i = 0; $i < 1; $i++) {
$row =mysqli_fetch_assoc($result);
} $emparray[] = $row;
echo $emparray ;
mysqli_close($connection);
?>
Does the Java &= operator apply & or &&?
From the Java Language Specification - 15.26.2 Compound Assignment Operators.
A compound assignment expression of the form
E1 op= E2is equivalent toE1 = (T)((E1) op (E2)), whereTis the type ofE1, except thatE1is evaluated only once.
So a &= b; is equivalent to a = a & b;.
(In some usages, the type-casting makes a difference to the result, but in this one b has to be boolean and the type-cast does nothing.)
And, for the record, a &&= b; is not valid Java. There is no &&= operator.
In practice, there is little semantic difference between a = a & b; and a = a && b;. (If b is a variable or a constant, the result is going to be the same for both versions. There is only a semantic difference when b is a subexpression that has side-effects. In the & case, the side-effect always occurs. In the && case it occurs depending on the value of a.)
On the performance side, the trade-off is between the cost of evaluating b, and the cost of a test and branch of the value of a, and the potential saving of avoiding an unnecessary assignment to a. The analysis is not straight-forward, but unless the cost of calculating b is non-trivial, the performance difference between the two versions is too small to be worth considering.
Create view with primary key?
You cannot create a primary key on a view. In SQL Server you can create an index on a view but that is different to creating a primary key.
If you give us more information as to why you want a key on your view, perhaps we can help with that.
How can I get jQuery to perform a synchronous, rather than asynchronous, Ajax request?
With async: false you get yourself a blocked browser.
For a non blocking synchronous solution you can use the following:
ES6/ECMAScript2015
With ES6 you can use a generator & the co library:
beforecreate: function (node, targetNode, type, to) {
co(function*(){
let result = yield jQuery.get('http://example.com/catalog/create/' + targetNode.id + '?name=' + encode(to.inp[0].value));
//Just use the result here
});
}
ES7
With ES7 you can just use asyc await:
beforecreate: function (node, targetNode, type, to) {
(async function(){
let result = await jQuery.get('http://example.com/catalog/create/' + targetNode.id + '?name=' + encode(to.inp[0].value));
//Just use the result here
})();
}
Debug vs Release in CMake
// CMakeLists.txt : release
set(CMAKE_CONFIGURATION_TYPES "Release" CACHE STRING "" FORCE)
// CMakeLists.txt : debug
set(CMAKE_CONFIGURATION_TYPES "Debug" CACHE STRING "" FORCE)
How to view UTF-8 Characters in VIM or Gvim
If Japanese people come here, please add the following lines to your ~/.vimrc
set encoding=utf-8
set fileencodings=iso-2022-jp,euc-jp,sjis,utf-8
set fileformats=unix,dos,mac
PHP function to generate v4 UUID
How about using mysql to generate the uuid for you?
$conn = new mysqli($servername, $username, $password, $dbname, $port);
$query = 'SELECT UUID()';
echo $conn->query($query)->fetch_row()[0];
Creating a static class with no instances
There are two ways to do that (Python 2.6+):
static method
class Klass(object):
@staticmethod
def static_method():
print "Hello World"
Klass.static_method()
module
your module file, called klass.py
def static_method():
print "Hello World"
your code:
import klass
klass.static_method()
Jquery checking success of ajax post
using jQuery 1.8 and above, should use the following:
var request = $.ajax({
type: 'POST',
url: 'mmm.php',
data: { abc: "abcdefghijklmnopqrstuvwxyz" } })
.done(function(data) { alert("success"+data.slice(0, 100)); })
.fail(function() { alert("error"); })
.always(function() { alert("complete"); });
check out the docs as @hitautodestruct stated.
Get selected element's outer HTML
node.cloneNode() hardly seems like a hack. You can clone the node and append it to any desired parent element, and also manipulate it by manipulating individual properties, rather than having to e.g. run regular expressions on it, or add it in to the DOM, then manipulate it afterwords.
That said, you could also iterate over the attributes of the element to construct an HTML string representation of it. It seems likely this is how any outerHTML function would be implemented were jQuery to add one.
How to loop through key/value object in Javascript?
for (var key in data) {
alert("User " + data[key] + " is #" + key); // "User john is #234"
}
How to check all versions of python installed on osx and centos
The more easy way its by executing the next command:
ls -ls /usr/bin/python*
Output look like this:
/usr/bin/python /usr/bin/python2.7 /usr/bin/pythonw
/usr/bin/python-config /usr/bin/python2.7-config /usr/bin/pythonw2.7
Reading a single char in Java
Using nextline and System.in.read as often proposed requires the user to hit enter after typing a character. However, people searching for an answer to this question, may also be interested in directly respond to a key press in a console!
I found a solution to do so using jline3, wherein we first change the terminal into rawmode to directly respond to keys, and then wait for the next entered character:
var terminal = TerminalBuilder.terminal()
terminal.enterRawMode()
var reader = terminal.reader()
var c = reader.read()
<dependency>
<groupId>org.jline</groupId>
<artifactId>jline</artifactId>
<version>3.12.3</version>
</dependency>
Android studio - Failed to find target android-18
Check the local.properties file in your Studio Project. Chances are that the property sdk.dir points to the wrong folder if you had set/configured a previous android sdk from pre-studio era. This was the solution in my case.
div inside php echo
You can use the below sample, also you dont need the else clause to print nothing!
<?php if ( ($cart->count_product) > 0) { ?>
<div class="my_class">
<?php print $cart->count_product; ?>
</div>
<?php } ?>
Jquery: How to check if the element has certain css class/style
if ($("element class or id name").css("property") == "value") {
your code....
}
OrderBy pipe issue
Please see https://angular.io/guide/pipes#appendix-no-filterpipe-or-orderbypipe for the full discussion. This quote is most relevant. Basically, for large scale apps that should be minified aggressively the filtering and sorting logic should move to the component itself.
"Some of us may not care to minify this aggressively. That's our choice. But the Angular product should not prevent someone else from minifying aggressively. Therefore, the Angular team decided that everything shipped in Angular will minify safely.
The Angular team and many experienced Angular developers strongly recommend that you move filtering and sorting logic into the component itself. The component can expose a filteredHeroes or sortedHeroes property and take control over when and how often to execute the supporting logic. Any capabilities that you would have put in a pipe and shared across the app can be written in a filtering/sorting service and injected into the component."
Adding a month to a date in T SQL
Look at DATEADD
SELECT DATEADD(mm, 1, OrderDate)AS TimeFrame
Here's the MSDN
In your case
...WHERE reference_dt = DATEADD(MM,1, myColDate)
How do I get to IIS Manager?
First of all, you need to check that the IIS is installed in your machine, for that you can go to:
Control Panel --> Add or Remove Programs --> Windows Features --> And Check if Internet Information Services is installed with at least the 'Web Administration Tools' Enabled and The 'World Wide Web Service'
If not, check it, and Press Accept to install it.
Once that is done, you need to go to Administrative Tools in Control Panel and the IIS Will be there. Or simply run inetmgr (after Win+R).
Edit:
You should have something like this:
How do I check when a UITextField changes?
This is how you can add a textField text change listener using Swift 3:
Declare your class as UITextFieldDelegate
override func viewDidLoad() {
super.viewDidLoad()
textField.delegate = self
textField.addTarget(self, action: #selector(UITextFieldDelegate.textFieldShouldEndEditing(_:)), for: UIControlEvents.editingChanged)
}
Then just traditionally add a textFieldShouldEndEditing function:
func textFieldShouldEndEditing(_ textField: UITextField) -> Bool { // do stuff
return true
}
C# : Converting Base Class to Child Class
I'm surprised AutoMapper hasn't come up as an answer.
As is clear from all the previous answers, you cannot do the typecast. However, using AutoMapper, in a few lines of code you can have a new SkyfilterClient instantiated based on an existing NetworkClient.
In essence, you would put the following where you are currently doing your typecasting:
using AutoMapper;
...
// somewhere, your network client was declared
var existingNetworkClient = new NetworkClient();
...
// now we want to type-cast, but we can't, so we instantiate using AutoMapper
AutoMapper.Mapper.CreateMap<NetworkClient, SkyfilterClient>();
var skyfilterObject = AutoMapper.Mapper.Map<SkyfilterClient>(existingNetworkClient);
Here's a full-blown example:
public class Vehicle
{
public int NumWheels { get; set; }
public bool HasMotor { get; set; }
}
public class Car: Vehicle
{
public string Color { get; set; }
public string SteeringColumnStyle { get; set; }
}
public class CarMaker
{
// I am given vehicles that I want to turn into cars...
public List<Car> Convert(List<Vehicle> vehicles)
{
var cars = new List<Car>();
AutoMapper.Mapper.CreateMap<Vehicle, Car>(); // Declare that we want some automagic to happen
foreach (var vehicle in vehicles)
{
var car = AutoMapper.Mapper.Map<Car>(vehicle);
// At this point, the car-specific properties (Color and SteeringColumnStyle) are null, because there are no properties in the Vehicle object to map from.
// However, car's NumWheels and HasMotor properties which exist due to inheritance, are populated by AutoMapper.
cars.Add(car);
}
return cars;
}
}
MySQL select one column DISTINCT, with corresponding other columns
SELECT DISTINCT (column1), column2
FROM table1
GROUP BY column1
401 Unauthorized: Access is denied due to invalid credentials
I had this issue on IIS 10. This is how I fixed it.
- Open IIS
- Select The Site
- Open Authentication
- Edit Anonymous Authentication
- Select Application Pool Identity
Hide vertical scrollbar in <select> element
Like Guffa said, you cannot reliably get that much control over native controls. The best way is probably to make a box of elements with radio buttons beside each item, then use labels and JavaScript to make the 'rows' interactive, so clicking on a radio button or label will color the selected row.
Pass an array of integers to ASP.NET Web API?
If you want to list/ array of integers easiest way to do this is accept the comma(,) separated list of string and convert it to list of integers.Do not forgot to mention [FromUri] attriubte.your url look like:
...?ID=71&accountID=1,2,3,289,56
public HttpResponseMessage test([FromUri]int ID, [FromUri]string accountID)
{
List<int> accountIdList = new List<int>();
string[] arrAccountId = accountId.Split(new char[] { ',' });
for (var i = 0; i < arrAccountId.Length; i++)
{
try
{
accountIdList.Add(Int32.Parse(arrAccountId[i]));
}
catch (Exception)
{
}
}
}
React onClick function fires on render
JSX is used with ReactJS as it is very similar to HTML and it gives programmers feel of using HTML whereas it ultimately transpiles to a javascript file.
Writing a for-loop and specifying function as {this.props.removeTaskFunction(todo)} will execute the functions whenever the loop is triggered .
To stop this behaviour we need to return the function to onClick.
The fat arrow function has a hidden return statement along with the bind property. Thus it returns the function to OnClick as Javascript can return functions too !!!!!
Use -
onClick={() => { this.props.removeTaskFunction(todo) }}
which means-
var onClick = function() {
return this.props.removeTaskFunction(todo);
}.bind(this);
When to use the different log levels
It's an old topic, but still relevant. This week, I wrote a small article about it, for my colleagues. For that purpose, I also created this cheat sheet, because I couldn't find any online.
Make a div fill up the remaining width
Try out something like this:
<style>
#divMain { width: 500px; }
#left-div { width: 100px; float: left; background-color: #fcc; }
#middle-div { margin-left: 100px; margin-right: 100px; background-color: #cfc; }
#right-div { width: 100px; float: right; background-color: #ccf; }
</style>
<div id="divMain">
<div id="left-div">
left div
</div>
<div id="right-div">
right div
</div>
<div id="middle-div">
middle div<br />bit taller
</div>
</div>
divs will naturally take up 100% width of their container, there is no need to explicitly set this width. By adding a left/right margin the same as the two side divs, it's own contents is forced to sit between them.
Note that the "middle div" goes after the "right div" in the HTML