java hmac/sha512 generation

Question

I have this php code which generate a HMAC (and not a simple message digest):

Answer 1

try that :

private String generateHMAC( String datas )
{
    MessageDigest md = MessageDigest.getInstance("SHA-512");

    md.update(datas.getBytes("UTF-8")); // Change this to "UTF-16" if needed
    byte[] digest = md.digest();

    StringBuffer hexString = new StringBuffer();
    for (int i=0;i<digest.length;i++) {
        hexString.append(Integer.toHexString(0xFF & digest[i]));
    }

    return  hexString.toString();
}

Answer 2

You simply forgot to mimic pack()'s behavior in your Java code (whatever you need that for).

Use

final SecretKeySpec secretKey = new SecretKeySpec( DatatypeConverter.parseHexBinary(PayboxConstants.KEY), "HmacSHA512" );

In your Java Code.

Where DatatypeConverter.parseHexBinary() is from the JAXB API.

Alternatively, if you don't want to include JAXB just for the purpose of converting HEX strings to bytes, you might want to use the code posted here.

Answer 3

I use this for SHA 512 in Java. It might help:

public static String sha512 ( String str )
    {
        try
        {
            return sha512 ( str.getBytes ( "UTF-8" ) );
        }
        catch ( UnsupportedEncodingException e )
        {
            e.printStackTrace ( );
            return "";
        }
    }

public static String sha512 ( byte[] array )
{
    try
    {
        MessageDigest m = MessageDigest.getInstance ( "SHA-512" );
        m.update ( array );
        String hash = new BigInteger ( 1, m.digest ( ) ).toString ( 16 );
        while ( hash.length ( ) < 32 )
        {
            hash = "0" + hash;
        }
        return hash;
    }
    catch ( NoSuchAlgorithmException e )
    {
        e.printStackTrace ( );
        return "";
    }
}

I also remember that there is detailed answer about MD-5 in a post in stackoverflow (just the algorythm is different)