String msg = "Message for signing";
byte[] msgHash = Hash.sha3(msg.getBytes());
Sign.SignatureData signature =
Sign.signMessage(msgHash, keyPair, false);
System.out.println("Msg: " + msg);
System.out.println("Msg hash: " + Hex.toHexString(msgHash));
"Signature: [v = %d, r = %s, s = %s]\n",
Hex.toHexString(signature.getR()),
Hex.toHexString(signature.getS()));