How to encrypt and decrypt String with my passphrase in Java Pc not mobile platform

Question

I want to encrypt a string and then put it on a file  Also want to decrypt it when I want   I don   t need very strong security  I just want to make it harder to get my data others   I tried several ways  Here are these   Md5 Encryption   How to hash a string in Android   public static final String md5 final String toEncrypt            try               final MessageDigest digest   MessageDigest getInstance  md5                digest update toEncrypt getBytes                 final byte   bytes   digest digest                final StringBuilder sb   new StringBuilder                for  int i   0  i  lt  bytes length  i                      sb append String format   02X   bytes i                               return sb toString   toLowerCase              catch  Exception exc                return        Impossibru                    I tried this function and able to encrypt a string but I can   t decrypt data from it  So it is not the solution   DES Encryption   Encrypt and decrypt a String in java  Here passphrase is Auto generated  Is always passphrase will same on all time  Then where is my security  So it is not my solution too   AES Encryption   How do I encrypt decrypt a string with another string as a password   I also tried Aes from this link  Here key is also auto generated   Is there any other way

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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

User · Answer

I just want to add that if you want to somehow store the encrypted byte array as String and then retrieve it and decrypt it  often for obfuscation of database values  you can use this approach   import java security Key  import javax crypto Cipher  import javax crypto spec SecretKeySpec  public class StrongAES        public void run                  try                        String text    Hello World               String key    Bar12345Bar12345      128 bit key                Create key and cipher             Key aesKey   new SecretKeySpec key getBytes     AES                Cipher cipher   Cipher getInstance  AES                   encrypt the text             cipher init Cipher ENCRYPT MODE  aesKey               byte   encrypted   cipher doFinal text getBytes                  StringBuilder sb   new StringBuilder                for  byte b  encrypted                    sb append  char b                                 the encrypted String             String enc   sb toString                System out println  encrypted     enc                   now convert the string to byte array                for decryption             byte   bb   new byte enc length                 for  int i 0  i lt enc length    i                      bb i     byte  enc charAt i                                 decrypt the text             cipher init Cipher DECRYPT MODE  aesKey               String decrypted   new String cipher doFinal bb                System err println  decrypted     decrypted                      catch Exception e                         e printStackTrace                        public static void main String   args                 StrongAES app   new StrongAES            app run

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Use This This Will work For sure  import java io IOException  import java io UnsupportedEncodingException  import java security GeneralSecurityException  import javax crypto Cipher  import javax crypto SecretKey  import javax crypto SecretKeyFactory  import javax crypto spec PBEKeySpec  import javax crypto spec PBEParameterSpec  import sun misc BASE64Decoder  import sun misc BASE64Encoder   public class ProtectedConfigFile        private static final char   PASSWORD    enfldsgbnlsngdlksdsgm  toCharArray        private static final byte   SALT      byte  0xde   byte  0x33   byte  0x10   byte  0x12   byte  0xde   byte  0x33               byte  0x10   byte  0x12          public static void main String   args  throws Exception           String originalPassword    Aman           System out println  Original password      originalPassword           String encryptedPassword   encrypt originalPassword           System out println  Encrypted password      encryptedPassword           String decryptedPassword   decrypt encryptedPassword           System out println  Decrypted password      decryptedPassword              private static String encrypt String property  throws GeneralSecurityException  UnsupportedEncodingException           SecretKeyFactory keyFactory   SecretKeyFactory getInstance  PBEWithMD5AndDES            SecretKey key   keyFactory generateSecret new PBEKeySpec PASSWORD            Cipher pbeCipher   Cipher getInstance  PBEWithMD5AndDES            pbeCipher init Cipher ENCRYPT MODE  key  new PBEParameterSpec SALT  20            return base64Encode pbeCipher doFinal property getBytes  UTF-8                 private static String base64Encode byte   bytes               NB  This class is internal  and you probably should use another impl         return new BASE64Encoder   encode bytes              private static String decrypt String property  throws GeneralSecurityException  IOException           SecretKeyFactory keyFactory   SecretKeyFactory getInstance  PBEWithMD5AndDES            SecretKey key   keyFactory generateSecret new PBEKeySpec PASSWORD            Cipher pbeCipher   Cipher getInstance  PBEWithMD5AndDES            pbeCipher init Cipher DECRYPT MODE  key  new PBEParameterSpec SALT  20            return new String pbeCipher doFinal base64Decode property     UTF-8               private static byte   base64Decode String property  throws IOException              NB  This class is internal  and you probably should use another impl         return new BASE64Decoder   decodeBuffer property

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The code marked as the solution did not work for me  This was my solution         http   www java2s com Code Java Security EncryptingaStringwithDES htm    https   stackoverflow com questions 23561104 how-to-encrypt-and-decrypt-string-with-my-passphrase-in-java-pc-not-mobile-plat     package encryptiondemo   import javax crypto Cipher  import javax crypto KeyGenerator  import javax crypto SecretKey  import javax crypto spec SecretKeySpec               author zchumager     public class EncryptionDemo      Cipher ecipher    Cipher dcipher     EncryptionDemo SecretKey key  throws Exception       ecipher   Cipher getInstance  AES        dcipher   Cipher getInstance  AES        ecipher init Cipher ENCRYPT MODE  key       dcipher init Cipher DECRYPT MODE  key          public String encrypt String str  throws Exception          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          public String decrypt String str  throws Exception          Decode base64 to get bytes     byte   dec   new sun misc BASE64Decoder   decodeBuffer str        byte   utf8   dcipher doFinal dec           Decode using utf-8     return new String utf8   UTF8              public static void main String args     throws Exception                String data    Don t tell anybody            String k    Bar12345Bar12345              SecretKey key   KeyGenerator getInstance  AES   generateKey            SecretKey key   new SecretKeySpec k getBytes     AES            EncryptionDemo encrypter   new EncryptionDemo key            System out println  Original String      data            String encrypted   encrypter encrypt data            System out println  Encrypted String      encrypted            String decrypted   encrypter decrypt encrypted            System out println  Decrypted String      decrypted

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My requirement was to keep the password in a config file in encrypted form and decrypt when the program runs  For this I used the jasypt library  jasypt-1 9 3 jar   This is a very good library and we can accomplish the task with just 4 lines of code   First  after adding jar to my project I imported the below library   import org jasypt util text AES256TextEncryptor    Then I created the below method  I then called this method by passing the text which I need to encrypt in password parameter  Using aesEncryptor encrypt method  I encrypted the password which is stored to the myEncryptedPassword variable      public void EncryptPassword String password           AES256TextEncryptor aesEncryptor   new AES256TextEncryptor        aesEncryptor setPassword  mypassword        String myEncryptedPassword   aesEncryptor encrypt password       System out println myEncryptedPassword               You might have noticed the method setPassword method and the value mypassword is used in the above code  This is to make sure that no one can decrypt the password even if they use the encrypted password using the same library   Now I can see the value in the myEncryptedPassword variable something like h9oJ4P5P8ToRy38wvK11PUQCBrT1oH zbMWuMrbOlI0rfZrj qSg6f u0jctOs ZUf9t3shiwnEt05 nq8bnag    This is the encrypted password  Keep this value in the config file   I then created the below method to decrypt the password to be used in my program  The value of passwordFromConfigFile is the encrypted text which I got from the EncryptPassword method  Note that you have to use the same password in the aesEncryptor setPassword method that you used to encrypt the password   public String DecryptPassword String passwordFromConfigFile                   AES256TextEncryptor aesEncryptor   new AES256TextEncryptor        aesEncryptor setPassword  mypassword        String decryptedPassword   aesEncryptor decrypt passwordFromConfigFile       return decryptedPassword         The variable decryptedPassword will now have the decrypted password value

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Both Encrypt and Decrypt with AES and DES Algoritham  This worked for me perfectly     GithubLink  Java Code For Encryption and Decryption  package decrypt   import java security Key  import java security NoSuchAlgorithmException  import javax crypto Cipher  import javax crypto KeyGenerator  import javax crypto NoSuchPaddingException  import javax crypto SecretKey  import javax crypto spec SecretKeySpec     Decrypt encrypted string into plain string with aes and Des algoritham     public class Decrypt    public String decrypt String str String k  throws Exception      Decode base64 to get bytes   Cipher  dcipher   Cipher getInstance  AES     Key aesKey   new SecretKeySpec k getBytes     AES     dcipher init dcipher DECRYPT MODE  aesKey     System out println aesKey   byte   dec   new sun misc BASE64Decoder   decodeBuffer str   byte   utf8   dcipher doFinal dec     System out println utf8      Decode using utf-8  return new String utf8   UTF8           public String encrypt String str String k  throws Exception    Cipher ecipher   Cipher getInstance  AES     Key aeskey   new SecretKeySpec k getBytes    AES     byte   utf8   str getBytes  UTF8     ecipher init ecipher ENCRYPT MODE  aeskey      byte   enc   ecipher doFinal utf8     return new sun misc BASE64Encoder   encode enc       public String encrypt String str String k String Algo  throws Exception    Cipher ecipher   Cipher getInstance Algo    Key aeskey   new SecretKeySpec k getBytes   Algo    byte   utf8   str getBytes  UTF8     ecipher init ecipher ENCRYPT MODE  aeskey      byte   enc   ecipher doFinal utf8     return new sun misc BASE64Encoder   encode enc      public String decrypt String str String k String Algo  throws Exception          Decode base64 to get bytes       Cipher  dcipher   Cipher getInstance Algo        Key aesKey   new SecretKeySpec k getBytes    Algo        dcipher init dcipher DECRYPT MODE  aesKey         System out println aesKey       byte   dec   new sun misc BASE64Decoder   decodeBuffer str       byte   utf8   dcipher doFinal dec         System out println utf8       Decode using utf-8      return new String utf8   UTF8         public static void main String args     throws Exception       String original    rakesh       String data    CfPcX0G e7TLKKMyyvrvrQ         String k    qertyuiopasdfghw     AES key length must be 16     String k1    qertyuio       DES key length must be 8      String data1    rakesh       String data2    nAtvNq7uHKE        String Algo   DES       String Algo1   AES       Decrypt decrypter   new Decrypt         System out println  Original String      original         System out println  encrypted String in DES      decrypter encrypt data1         k1 Algo         System out println  Decrypted String in DES      decrypter decrypt data2          k1 Algo         System out println  encrypted String in AES      decrypter encrypt data1         k Algo1         System out println  Decrypted String in AES      decrypter decrypt data         k Algo1

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package com example  import java security Key  import javax crypto Cipher  import javax crypto spec SecretKeySpec  public class StrongAES        public void run                  try                        String text    Hello World               String key    Bar12345Bar12345      128 bit key                Create key and cipher             Key aesKey   new SecretKeySpec key getBytes     AES                Cipher cipher   Cipher getInstance  AES                   encrypt the text             cipher init Cipher ENCRYPT MODE  aesKey               byte   encrypted   cipher doFinal text getBytes                 System err println new String encrypted                   decrypt the text             cipher init Cipher DECRYPT MODE  aesKey               String decrypted   new String cipher doFinal encrypted                System err println decrypted                     catch Exception e                         e printStackTrace                        public static void main String   args                 StrongAES app   new StrongAES            app run

[java] How to encrypt and decrypt String with my passphrase in Java (Pc not mobile platform)?

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