question: private static String checksumMD5 ( String data ) { MessageDigest md5 = null ; try { md5 = MessageDigest . getInstance ( "MD5" ) ; } catch ( NoSuchAlgorithmException ex ) { throw new RuntimeException ( "Unable to create MD5 instance" , ex ) ; } return hexEncode ( md5 . digest ( data . getBytes ( ) ) ) ; }
target:  MD5 version of the "H()" function from rfc2617.