sign method
Implementation
@override
//SignedMessage sign(Uint8List message, {bool extended: false}) => super.sign(message, extended: true);
SignedMessage sign(List<int> message) {
// signed message
var sm = Uint8List(message.length + TweetNaCl.signatureLength);
var kb = (prefix + publicKey).toUint8List();
final result = TweetNaCl.crypto_sign(
sm, -1, message.toUint8List(), 0, message.length, kb,
extended: true);
if (result != 0) {
throw Exception('Signing the massage is failed');
}
return SignedMessage.fromList(signedMessage: sm);
}