@Override
  public String sign(String message, byte[] key) {
    return signer.sign(message, key);
  }
@Override
  public String sign(String message, byte[] key) {
    return signer.sign(message, key);
  }
@ Override public String sign ( String message , byte [ ] key ) { return signer . sign ( message , key ) ; }
Signs the given String using the given key. <br>

@param message The message to sign.
@param key The private key to sign with.
@return A hexadecimal encoded signature.
Signs the given String using the given key . <br >