using System;

using System.Security.Cryptography;

using System.Text;

​

public class Program

{

    //Add your public key here

    private static string RSAKey = $"-----BEGIN PUBLIC KEY-----MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAvWpIQFjQQCPpaIlJKpegirp5kLkzLB1AxHmnLk73D3TJbAGqr1QmlsWDBtMPMRpdzzUM7ZwX3kzhIuATV4Pe7RKp3nZlVmcrT0YCQXBrTwqZNh775z58GP2kZs+gVfNqBampJPzSB/hB62KkByhECn6grrRjiAVwJyZVEvs/2vrxaEpO+aE16emtX12RgI5JdzdOiNyZEQteU6zRBRJEocPWVxExaOpVVVJ5+UnW0LcalzA+lRGRTrQJ5JguAPiAOzRPTK/lYFFpCAl/F8wtoAVG1c8zO2NcQ0Pko+fmeidRFxJ/did2btV+9Mkze3mBphwFmvnxa35LF+Cs/XJHDwIDAQAB-----END PUBLIC KEY-----";

    private static string dataToEncrypt = "4242424242424242";

    public static void Main()

    {

        var defaultPaddingMode = GetModeFromPaddingAndDigest(null, null);

        var pkcs1PaddingMode = GetModeFromPaddingAndDigest("PKCS1", "");

        var oaepSHA1PaddingMode = GetModeFromPaddingAndDigest("OAEP", "SHA1");

        var oaepSHA256PaddingMode = GetModeFromPaddingAndDigest("OAEP", "SHA256");

        var oaepSHA384PaddingMode = GetModeFromPaddingAndDigest("OAEP", "SHA384");

        var oaepSHA512PaddingMode = GetModeFromPaddingAndDigest("OAEP", "SHA512");

        Console.WriteLine("Default Encryption:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, defaultPaddingMode));

        Console.WriteLine();

        Console.WriteLine("Encryption - PKCS1:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, pkcs1PaddingMode));

        Console.WriteLine();

        Console.WriteLine("Encryption - OAEP SHA1:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, oaepSHA1PaddingMode));

        Console.WriteLine();

        Console.WriteLine("Encryption - OAEP SHA256:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, oaepSHA256PaddingMode));

        Console.WriteLine();

        Console.WriteLine("Encryption -  OAEP SHA384:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, oaepSHA384PaddingMode));

        Console.WriteLine();

        Console.WriteLine("Encryption - OAEP SHA512:");

        Console.WriteLine(RSAEncrypt(dataToEncrypt, oaepSHA512PaddingMode));

    }

    private static string RSAEncrypt(string data, RSAEncryptionPadding paddingMode){

        using var cryptoProvider = RSA.Create();

        cryptoProvider.ImportFromPem(RSAKey.Replace("\\r\\n", "\r\n"));

        return Convert.ToBase64String(cryptoProvider.Encrypt(Encoding.UTF8.GetBytes(dataToEncrypt), paddingMode));

    }

    private static RSAEncryptionPadding GetModeFromPaddingAndDigest(string paddingMode, string digest) => paddingMode switch

    {

        null => RSAEncryptionPadding.Pkcs1,

        "PKCS1" => RSAEncryptionPadding.Pkcs1,

        "OAEP" => digest switch

            {

                null => RSAEncryptionPadding.OaepSHA1,

                "SHA1" => RSAEncryptionPadding.OaepSHA1,

                "SHA256" => RSAEncryptionPadding.OaepSHA256,

                "SHA384" => RSAEncryptionPadding.OaepSHA384,

                "SHA512" => RSAEncryptionPadding.OaepSHA512,

                _ => throw new Exception("Invalid Digest Mode")

            },

        _ => throw new Exception("Invalid Padding Mode")

    };

}