How to SHA1 hash a string in Android

Question

In Objective C I ve been using the following code to hash a string   - NSString    sha1  NSString  stringToHash           const char  cStr    stringToHash UTF8String       unsigned char result 20       CC SHA1  cStr  strlen cStr   result        return  NSString stringWithFormat    02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X           result 0   result 1   result 2   result 3            result 4   result 5   result 6   result 7           result 8   result 9   result 10   result 11           result 12   result 13   result 14   result 15           result 16   result 17   result 18   result 19                   Now I need the same for Android but can t find out how to do it  I ve been looking for example at this  Make SHA1 encryption on Android   but that doesn t give me the same result as on iPhone  Can anyone point me in the right direction

User · Answer

Here is the Kotlin version to get SHA encryption string.

import java.security.MessageDigest

object HashUtils {
    fun sha512(input: String) = hashString("SHA-512", input)

    fun sha256(input: String) = hashString("SHA-256", input)

    fun sha1(input: String) = hashString("SHA-1", input)

    /**
     * Supported algorithms on Android:
     *
     * Algorithm    Supported API Levels
     * MD5          1+
     * SHA-1        1+
     * SHA-224      1-8,22+
     * SHA-256      1+
     * SHA-384      1+
     * SHA-512      1+
     */
    private fun hashString(type: String, input: String): String {
        val HEX_CHARS = "0123456789ABCDEF"
        val bytes = MessageDigest
                .getInstance(type)
                .digest(input.toByteArray())
        val result = StringBuilder(bytes.size * 2)

        bytes.forEach {
            val i = it.toInt()
            result.append(HEX_CHARS[i shr 4 and 0x0f])
            result.append(HEX_CHARS[i and 0x0f])
        }

        return result.toString()
    }
}

Its originally posted here: https://www.samclarke.com/kotlin-hash-strings/

User · Answer

A simpler SHA-1 method   updated from the commenter s suggestions  also using a massively more efficient byte- string algorithm   String sha1Hash  String toHash         String hash   null      try               MessageDigest digest   MessageDigest getInstance   SHA-1             byte   bytes   toHash getBytes  UTF-8            digest update bytes  0  bytes length           bytes   digest digest                This is  55x faster than looping and String formating           hash   bytesToHex  bytes              catch  NoSuchAlgorithmException e                 e printStackTrace              catch  UnsupportedEncodingException e                 e printStackTrace              return hash        http   stackoverflow com questions 9655181 convert-from-byte-array-to-hex-string-in-java final protected static char   hexArray    0123456789ABCDEF  toCharArray    public static String bytesToHex  byte   bytes         char   hexChars   new char  bytes length   2        for  int j   0  j  lt  bytes length  j                   int v   bytes  j    amp  0xFF          hexChars  j   2     hexArray  v  gt  gt  gt  4            hexChars  j   2   1     hexArray  v  amp  0x0F              return new String  hexChars

User · Answer

If you can get away with using Guava it is by far the simplest way to do it  and you don t have to reinvent the wheel   final HashCode hashCode   Hashing sha1   hashString yourValue  Charset defaultCharset       You can then take the hashed value and get it as a byte    as an int  or as a long   No wrapping in a try catch  no shenanigans  And if you decide you want to use something other than SHA-1  Guava also supports sha256  sha 512  and a few I had never even heard about like adler32 and murmur3

User · Answer

Totally based on  Whymarrh s answer  this is my implementation  tested and working fine  no dependencies   public static String getSha1Hex String clearString        try               MessageDigest messageDigest   MessageDigest getInstance  SHA-1            messageDigest update clearString getBytes  UTF-8             byte   bytes   messageDigest digest            StringBuilder buffer   new StringBuilder            for  byte b   bytes                        buffer append Integer toString  b  amp  0xff    0x100  16  substring 1                      return buffer toString              catch  Exception ignored                ignored printStackTrace            return null

User · Answer

You don t need andorid for this  You can just do it in simple java    Have you tried a simple java example and see if this returns the right sha1    import java io UnsupportedEncodingException  import java security MessageDigest  import java security NoSuchAlgorithmException   public class AeSimpleSHA1       private static String convertToHex byte   data            StringBuilder buf   new StringBuilder            for  byte b   data                int halfbyte    b  gt  gt  gt  4   amp  0x0F              int two halfs   0              do                   buf append  0  lt   halfbyte   amp  amp   halfbyte  lt   9     char    0    halfbyte     char    a     halfbyte - 10                     halfbyte   b  amp  0x0F                while  two halfs    lt  1                     return buf toString               public static String SHA1 String text  throws NoSuchAlgorithmException  UnsupportedEncodingException           MessageDigest md   MessageDigest getInstance  SHA-1            byte   textBytes   text getBytes  iso-8859-1            md update textBytes  0  textBytes length           byte   sha1hash   md digest            return convertToHex sha1hash             Also share what your expected sha1 should be  Maybe ObjectC is doing it wrong

User · Answer

String format   02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X 02X   result 0   result 1   result 2   result 3        result 4   result 5   result 6   result 7       result 8   result 9   result 10   result 11       result 12   result 13   result 14   result 15       result 16   result 17   result 18   result 19

User · Answer

Android comes with Apache s Commons Codec - or you add it as dependency  Then do   String myHexHash   DigestUtils shaHex myFancyInput     That is the old deprecated method you get with Android 4 by default  The new versions of DigestUtils bring all flavors of shaHex   methods like sha256Hex   and also overload the methods with different argument types   http   commons apache org proper commons-codec  javadocs api-release org apache commons codec digest DigestUtils html

User · Answer

The method you are looking for is not specific to Android  but to Java in general  You re looking for the MessageDigest  import java security MessageDigest    An implementation of a sha512 String s  method can be seen here  and the change for a SHA-1 hash would be changing line 71 to   MessageDigest md   MessageDigest getInstance  SHA-1

User · Answer

final MessageDigest digest   MessageDigest getInstance  SHA-1    result   digest digest stringToHash getBytes  UTF-8         Another way to construct HEX  my previous post was only the method like your solution StringBuilder sb   new StringBuilder     for  byte b   result     This is your byte   result         sb append String format   02X   b       String messageDigest   sb toString

[android] How to SHA1 hash a string in Android?

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