public (byte[], byte[], byte[]) GetSignature(TxTemplate transaction, string serializedTransaction, int index, string privKey)
{
var pubKeyBuffer = Encoders.Base58.DecodeData(transaction.Outputs[index].PublicKeys[0]);
string transactionUniqueFulfillment = GetUniqueFulfillment(transaction, serializedTransaction, index);
var transactionHash = HashingUtils.ComputeSha3Hash(Encoding.UTF8.GetBytes(transactionUniqueFulfillment));
var signature = CryptographyUtility.Ed25519Sign(transactionHash, Encoders.Base58.DecodeData(privKey));
return(transactionHash, pubKeyBuffer, signature);
}