using System;

using System.Text;

using System.Text.Json;

using System.Collections.Generic;

using Nethereum.Util;

using Nethereum.Signer;

using Nethereum.Hex.HexConvertors.Extensions;

​

namespace SigningAddress {

​

    public class Data {

        public int NewAccountID { get; set; }

        public string? PubKey { get; set; }

        public bool IsETH { get; set; }

        public int UserID { get; set; }

        public DateTimeOffset CreatedByUser { get; set; }

    }

​

    public class Program

    {

        public static void Main()

        {

            string jsonString =

            @"{""NewAccountID"":5,""PubKey"":""BCT4ALtlDp9SkeQaN9SsLm2rcnhC8IAAwFqHbOYiR2U2vRusCalc2WTyvYjfzcVEv6zWXV+4WDXqgcwSCjVrUNo="",""IsETH"":true,""UserID"":4,""NodeID"":1,""CreatedByUser"":""2022-07-19T02:31:42.4757528Z""}";

​

            Data? dataObject = JsonSerializer.Deserialize<Data>(jsonString);

            Console.WriteLine($"Object: {jsonString}");

            //This sample demonstrates how to sign a message with a private key 

            //and validate the signer later on by recovering the address of the signature.

​

            //Given an address with a private key

            var address = "0xd864e8c9Eb1525a759503F03aCF03149d344E671";

            var privateKey = "0xfaa4bff60e5aca00877a3511da0c56f4caa3047e1987df5879ce4ed3a8c373ea";

            Console.WriteLine($"Address {address} with private key: {privateKey}");

​

            //And a message to sign

            // var messageToSign = jsonString;

            // var messageToSign = JsonSerializer.Serialize<Data>(dataObject);

            var messageToSign = "wee test message 18/09/2017 02:55PM";

            //Message to be sign

            Console.WriteLine($"Message to be sign: {messageToSign})");

​

            //We can create an Ethereum signer. 

            //Note: the EthereumSigner is a specialised signer for messages that prefixes the messages with "x19Ethereum Signed Message:"

            var signer = new EthereumMessageSigner();

​

            //To sign a text message we UTF8 encoded it (byte array) first and then sign it

            var signature = signer.EncodeUTF8AndSign(messageToSign, new EthECKey(privateKey));

            Console.WriteLine($"Signature: {signature}");

            // Convert to base64

            var signatureBase64 = System.Convert.ToBase64String(System.Text.Encoding.UTF8.GetBytes(signature.Substring(2)));

            Console.WriteLine($"Signature in base64: {signatureBase64}");

​

            //To recover the address of the signer of a text message 

            //we first UTF8 encoded it (byte array) and then using the Elliptic Curve recovery we get the address.

            var addressRecovered = signer.EncodeUTF8AndEcRecover(messageToSign, signature);

​

            //We can validate the signature if the address matches

            Console.WriteLine($"Address recovered: {addressRecovered}");

        }

    }

}