using System;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        var customerCode = "9876543210"; // Paste your costumer code

        var nationalCode = "0123456789"; // Paste your national code

        var inputText = $"{customerCode}-{nationalCode}";

        var signText = SignByPrivateKey(inputText);     

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

        var isVerified = VerifyByPublickKey(inputText, signText);       

        Console.WriteLine($"Verified: {isVerified}");

    }

    public static string SignByPrivateKey(string inputText)

    {

        var inputBytes = Encoding.Unicode.GetBytes(inputText);

​

        using var rsa = RSA.Create();

        rsa.ImportFromPem(s_pemPrivateKey);

​

        var signedBytes = rsa.SignData(inputBytes, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);

​

        return Convert.ToBase64String(signedBytes);

    }

    public static bool VerifyByPublickKey(string inputText, string signature)

    {

        var inputBytes = Encoding.Unicode.GetBytes(inputText);

        var signBytes = Convert.FromBase64String(signature);

​

        using var rsa = RSA.Create();

        rsa.ImportFromPem(s_pemPublicKey);

        var isVerified = rsa.VerifyData(inputBytes, signBytes, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);

        return isVerified;

    }

    // Sample RSA 1024 bits private key

    // Generated by: https://cryptotools.net/rsagen

    // Paste your real PEM Formatted private key here

    static string s_pemPrivateKey = @"-----BEGIN RSA PRIVATE KEY-----

MIICWwIBAAKBgQCQq5094oTTQbD601MQNWkgQjHXbfuIWSqYxpWZgzpIxl1gUNi4

n6LMKZUW7JT1Wpp/9s4WaAhmdGAmHjCo8cRNvWo/B2XkwsXveH2XYnhbWDOv7zGy

ycjVl+aN01JN3XszbPrw5edhygXdJz2MiGeRBahm9kd04XjdiTS+mnDHbwIDAQAB

AoGASrEP4d+NjDSiVx28COZKfGkwqnUSJHdE0tPUcQmbke84Tn3vJoLk3lupqchD

r9kzY1XdWRwlGiCDc6qqnM8V9fW5v4GmKP6mGGOHwxocw8KIOnh53nptu6q/OoZm

5PK4n5qhISiA53wdYjkqe5jfrQBhqNLWb0YQqqtOdalD9IECQQDQTsgWjPHhQB30

ADl+3LVVOxie9EgJRHfAtSibedabNaMkThj8I1QJma2AdzCGfPk/tpL9lB25ymNI

8CXwdlu/AkEAscr0PJ1uMvgSJfmreIlLaFqyuhl4wwb/r9QNgHewDS1tCEyEEg+2

fnD6+TUmFSOn5z6oglhaHfemQSrVrXJAUQJAAwuDxUCeMIq9ZVmzfXVAeVR50akE

fI4xqfF7/HnVd0NbdSZnGxhxHArRDHWxkeW1xwamM2q83IBm3yQTieZRBQJAYGjf

vCbaZQUkQjd7BifdHj9gf43kcE1RRTVGBQ3iB6NEZqWnUGv41+PIFG7/saLeH4VY

tyXV6D4sh1YE/MLhoQJAZMNe4nEk+0+ajh1eUcw1F7POqY4tx4XYInNlLbe8f64l

ZKZ9NYJFINlZpo3wrUCoSoove37f0fPLZ1mkoU3yOw==

-----END RSA PRIVATE KEY-----

";

    // Sample RSA 1024 bits public key

    // Generated by: https://cryptotools.net/rsagen

    // Paste your real PEM Formatted private key here

    static string s_pemPublicKey = @"-----BEGIN PUBLIC KEY-----

MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCQq5094oTTQbD601MQNWkgQjHX

bfuIWSqYxpWZgzpIxl1gUNi4n6LMKZUW7JT1Wpp/9s4WaAhmdGAmHjCo8cRNvWo/

B2XkwsXveH2XYnhbWDOv7zGyycjVl+aN01JN3XszbPrw5edhygXdJz2MiGeRBahm

9kd04XjdiTS+mnDHbwIDAQAB

-----END PUBLIC KEY-----";

}