sign method
Implementation
@override
SignedMessage sign(Uint8List message) {
// signed message
var sm = Uint8List(message.length + TweetNaCl.signatureLength);
final result = TweetNaCl.crypto_sign(
sm, -1, Uint8List.fromList(message), 0, message.length, asTypedList);
if (result != 0) {
throw Exception('Signing the massage is failed');
}
return SignedMessage.fromList(signedMessage: sm);
}