using System;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var privKey = @"MIIC3TBXBgkqhkiG9w0BBQ0wSjApBgkqhkiG9w0BBQwwHAQIg9wOc+AemawCAggA

MAwGCCqGSIb3DQIJBQAwHQYJYIZIAWUDBAEqBBCKPg1CnAMGYFdMB4TMjA8oBIIC

gMGfNIf91BsAvPuCuneKPYvVUcJ5gxwTsBS/leAUUQl8OGJEWLQBxCQ6tNdBYeZY

vjdhqi74VZu7Gr56865UtN18O2lvZLU7Wmuu0UDrFgI3EBVW360A/HZXSla1DDOd

5GXqBodzzP5W2qyv2NI/PoGii/1KdY/MIjD6F+NnuYehTPUJBBrXtqibC7EV3C8I

yg3mJ4QzQ2cKktircL3kgLqLww3+vlcwCi82zpMSpRVHJjROdCCe80pJfRRLWYbV

Bv4XZsscLa/6EWiwkpEUMA4XSTtLc2COvkyHD7IHdquKfaXDTKJIiE8v/fHOQBrb

t3u6+71DgC2sOSA9tCHw4M5C43cjA5cW92rJlx+Lw0hw06Rq26DDaqdR0I2oJ/xW

HlvWE1k21/FCJwgrFTM1PFVYsURorvM+38FGnab0c9YkJKZaFgZbXjTowd/0Sq1E

pJDtQAlZ56JLegujzrxfkjAIJ6UWqq8XhR1SUFcAGDvhOAdA+hAp/qAp3aZ0N45E

npWdmeJ68ScOO6LApCx9+A42Fs5SZb/o5BKhzqD5P8sg2ll3p1RKYX7NrLBgiQkt

N/zp/uJSu70nTcaECE/iexlNfGg/bq9IcqcgxxLE5i73HClwxyN+37HwG9tvPE9T

qQElFAVB8gW/rgpVZrRVLMWsjBapvCzJ5EXX5oQ67W7m3mfktJ1Uk+DpXTfez3wv

HbukKjDbZ3ZH5JV3Ax2q8mNMG90+o1hIMEwu5IejtLH9ARfVuuuvwYJr1Afe6Wcg

1u+Czv+KYDOja0BFLLhcpP3AFvokVyBig/DcPMQbHWr+N0Sg3bYmY3FeRxMsKsf7

ih2drvtH8DJgti9uXYK+rns=";

        var privateKeyBytes = Convert.FromBase64String(privKey);

        var signer = RSA.Create();

        signer.ImportEncryptedPkcs8PrivateKey(new byte[] { }, privateKeyBytes, out _);

        var payload1 = "124c73c3-4324-48e9-a674-c476245685681647624568568";

        var signatureHash = signer.SignData(Encoding.UTF8.GetBytes(payload1), HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);

        var signature = Convert.ToBase64String(signatureHash);

        Console.WriteLine(signature);

    }

}