ECDSA

using System.Security.Cryptography;
using System.Text;

namespace ConsoleApp
{
    class Program
    {
        class ECDsaHelper
        {
            public CngAlgorithm Algorithm { get; set; }
            public Encoding Encoding { get; set; }

            public byte[] Key { get; set; }

            public ECDsaHelper(CngAlgorithm algorithm, Encoding encoding)
            {
                Algorithm = algorithm;
                Encoding = encoding;
            }

            public void CreateKey()
            {
                using (var dsa = new ECDsaCng())
                {
                    dsa.HashAlgorithm = Algorithm;
                    SetKey(dsa);
                }
            }

            internal byte[] SignData(byte[] dataInBytes)
            {
                byte[] signature = null;
                using (var dsa = GetECDsaCng())
                {
                    dsa.HashAlgorithm = Algorithm;

                    if (Key == null)
                    {
                        SetKey(dsa);
                    }

                    signature = dsa.SignData(dataInBytes);
                }

                return signature;
            }

            private void SetKey(ECDsaCng dsa)
            {
                Key = dsa.Key.Export(CngKeyBlobFormat.EccPublicBlob);
            }

            private static ECDsaCng GetECDsaCng()
            {
                return new ECDsaCng();
            }

            internal bool Validate(byte[] dataInBytes, byte[] signature)
            {
                using (var dsa = new ECDsaCng(CngKey.Import(Key, CngKeyBlobFormat.EccPublicBlob)))
                {
                    dsa.HashAlgorithm = Algorithm;

                    return dsa.VerifyData(dataInBytes, signature);
                }
            }
        }

        class SendPackage
        {
            public ECDsaHelper ECDsaHelper { get; set; }
            public string Data { get; set; }
            public byte[] Signature { get; set; }

            public SendPackage(ECDsaHelper eCDsaHelper)
            {
                ECDsaHelper = eCDsaHelper;
            }

            internal void SignData()
            {
                var dataInBytes = Encoding.UTF8.GetBytes(Data);
                Signature = ECDsaHelper.SignData(dataInBytes);
            }
        }

        class ReceivedPackage
        {
            public ECDsaHelper ECDsaHelper { get; set; }

            public string Data { get; set; }
            public byte[] Signature { get; set; }

            public ReceivedPackage(ECDsaHelper eCDsaHelper, string data, byte[] signature)
            {
                ECDsaHelper = eCDsaHelper;
                Data = data;
                Signature = signature;
            }

            internal bool ValidateData()
            {
                var result = ECDsaHelper.Validate(ECDsaHelper.Encoding.GetBytes(Data), Signature);
                return result;
            }
        }

        static void Main(string[] args)
        {
            var helper = new ECDsaHelper(CngAlgorithm.Sha512, Encoding.UTF8);
            helper.CreateKey();

            var sendPackage = new SendPackage(helper);
            sendPackage.Data = "data to send";
            sendPackage.SignData();

            var receiver = new ReceivedPackage(helper, sendPackage.Data, sendPackage.Signature);
            var result = receiver.ValidateData();
        }
    }
}

import System.Security.Cryptography.Cng to use this.