protected void engineUpdate(byte[] b,int off,int len) throws SignatureException {
  messageDigest.update(b,off,len);
  needsReset=true;
}

protected void engineUpdate ( byte [ ] b , int off , int len ) throws SignatureException { messageDigest . update ( b , off , len ) ; needsReset = true ; }
updates the data to be signed or verified , using the specified array of bytes , starting at the specified offset .
