question: private static String H ( String data ) { try { MessageDigest digest = MessageDigest . getInstance ( "MD5" ) ; return toHexString ( digest . digest ( data . getBytes ( ) ) ) ; } catch ( NoSuchAlgorithmException ex ) { throw new RuntimeException ( "Failed to instantiate an MD5 algorithm" , ex ) ; } }
target:  Defined in rfc 2617 as H(data) = MD5(data);