using System;

using System.IO;

using System.Security.Cryptography;

using System.Text;

using Org.BouncyCastle.Crypto;

using Org.BouncyCastle.Crypto.Parameters;

using Org.BouncyCastle.OpenSsl;

using Org.BouncyCastle.Security;

public class Program

{

    private static string privateKey = @"-----BEGIN RSA PRIVATE KEY-----

                                        MIIEpAIBAAKCAQEAqCKSZaUnkufLHBgS12FOxf8nyLMTHg/ZlRvNs3LcmV1bRV9Y

                                        hwTVlCQSrtOn87iGWtzlE8xeNizq9H5XI5OG527lTa+kBeYSaKrr9dExrBDGnsfH

                                        QA+P+R3J09B/jHsvMWxIrojJoGzHGHnegatsH+8vlpDOsuyGnSTwduCCC717sBCX

                                        Dt7G8ZkLcopFykxpBYbh/RPM/cbO+WTmmX9ag6kH4ZIQMibxQ4+xTt1a70Z/9dlP

                                        hxGPgkqgK4Ljh5plA3KFnCYazWoHZwYUyKGI8oyYepNxJBLdw62f3/PRCUd0jRRU

                                        0z1yTAp2GYtSmwbhoyNa5C6hQe3r/PbLMx7ecwIDAQABAoIBAQCTYfrCbwtJkzZP

                                        4iph8kKC/S96lr7jUzF/q2edLcqCBXvES9fmQy6VNSnLZm2LDu13KLsFp9fN1YH/

                                        39+yp9dRd7w5ZQV6xjrM1UcRq9bG5c210ZmvZfTmgl4w9ktYcYLk5+6uT+muXqwH

                                        oIyTThjxxVEJwtXtsbgud/rxuctFTd1VNpJwE0g/G8H9agPFC6Y1OV1/Y34UaNQt

                                        uxovhr+o14yyjalnSHYn0gx9MHe6hhGTyV/2rZduOkAUHG8I38Li/1O4wykEM4IX

                                        7CgGx5UQkIvf+Gdu69kT+1GCot6m/tnodZNlerbN+KU7WtBZumVAlF5kniWmqfRB

                                        SRHbiNhBAoGBAOsSRNMj2e1I9xf081p9bHb+nN10kmPG2SsuXDAhySZMRBU+PIp0

                                        UJXAqg55x9kLFcFFEqNh2hWa57R/2sGOSAkdPkcmnLsCJw2E9t4SieGqLNxsfozc

                                        y43fuYXVgfNHBJa5ZW9wVDn8dhr7HdUOGAZ1tw/fVhc+cHdAWCzLJwsfAoGBALca

                                        seKeT6RH03atDpb1G6Tgl7nqSbzQOf+rKp2t7j+yiBv7cw7vWKsUfTwX8M1QClT7

                                        KeeAdHsrk6Ai4nolvxv3l1sMu0+4BrxfRMubUj6LHudd9A+hosDdaPjucLg/Qoqo

                                        zIoS9RJ7yZoqTH99ssqEC13EKD3YNpJPwe79StYtAoGAIqYituyF5s/mfAWDCUeL

                                        gU6uWIYiPcrFn/PJat7QA3EiZ+8whUf3yNsJNfEFYByeLEq+II7/0kdu99AQso8C

                                        VzWURHCQkZATqY57xOf+ouCulB752FGDP3pGok+CRBWnu3/AT9jC0XlA/2EcWJcn

                                        O2yGezR0QCDX+vvlA1U+gAkCgYAIx0jb+ocK8z6aI/XdGuc2YmYjza23VaxSK5yh

                                        bqNLfn20CbwcbTEtEpBmfydWUI4OQPRjWu86sH4lYUbGYGTnLFmfTd71FXeNNGwR

                                        7uJkiTr0ELcQwMkSwgq0VIom6zF/gFQ+EmaZekHSGFEOk7Isr2P0HOFpBaKoJRbB

                                        JHegCQKBgQDkOOWkJs+cXd067zE1W7uw0BHmBHvq6PjLoXA563Vtp8nB3FI7Ow9W

                                        O5MGy7kQ8C69F19sZcTIDi9QWfhUJSw1PFtrsmFkzBkwGe3SvKB19VbROadJIC4b

                                        /ntmkgyD4LCB3c0JpDn4cm6dyJSO/HbN43Duo1XQtcdmRjGjPff8mg==

                                        -----END RSA PRIVATE KEY-----";

    private static string publicKey = @"-----BEGIN PUBLIC KEY-----

                                        MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAqCKSZaUnkufLHBgS12FO

                                        xf8nyLMTHg/ZlRvNs3LcmV1bRV9YhwTVlCQSrtOn87iGWtzlE8xeNizq9H5XI5OG

                                        527lTa+kBeYSaKrr9dExrBDGnsfHQA+P+R3J09B/jHsvMWxIrojJoGzHGHnegats

                                        H+8vlpDOsuyGnSTwduCCC717sBCXDt7G8ZkLcopFykxpBYbh/RPM/cbO+WTmmX9a

                                        g6kH4ZIQMibxQ4+xTt1a70Z/9dlPhxGPgkqgK4Ljh5plA3KFnCYazWoHZwYUyKGI

                                        8oyYepNxJBLdw62f3/PRCUd0jRRU0z1yTAp2GYtSmwbhoyNa5C6hQe3r/PbLMx7e

                                        cwIDAQAB

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

    public static void Main()

    {

        // 1

        {

            RSACryptoServiceProvider privateCSP = GetRSACryptoServiceProviderFromPem(privateKey, true);

            RSACryptoServiceProvider publicCSP = GetRSACryptoServiceProviderFromPem(publicKey, false);

​

            byte[] dataToSign = Encoding.UTF8.GetBytes("The quick brown fox jumps over the lazy dog");

            byte[] signature = privateCSP.SignData(dataToSign, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);

            Console.WriteLine(Convert.ToBase64String(signature));

            bool verified = publicCSP.VerifyData(dataToSign, signature, HashAlgorithmName.SHA1, RSASignaturePadding.Pkcs1);

            Console.WriteLine(verified);

        }

        // 2

        {

            RsaPrivateCrtKeyParameters privateKeyParameters = (RsaPrivateCrtKeyParameters)GetAsymmetricKeyParameterFromPem(privateKey, true);

            RsaKeyParameters publicKeyParameters = (RsaKeyParameters)GetAsymmetricKeyParameterFromPem(publicKey, false);

​

            ISigner signer = SignerUtilities.GetSigner("SHA1withRSA");

            signer.Init(true, privateKeyParameters);

            byte[] dataToSign = Encoding.UTF8.GetBytes("The quick brown fox jumps over the lazy dog");

            signer.BlockUpdate(dataToSign, 0, dataToSign.Length);

            byte[] signature = signer.GenerateSignature();

            Console.WriteLine(Convert.ToBase64String(signature));

​

            signer.Init(false, publicKeyParameters);

            signer.BlockUpdate(dataToSign, 0, dataToSign.Length);

            bool verified = signer.VerifySignature(signature);

            Console.WriteLine(verified);

        }

    }

    public static RSACryptoServiceProvider GetRSACryptoServiceProviderFromPem(string pem, bool isPrivate)

    {

        PemReader pemReader = new PemReader(new StringReader(pem));

        object key = pemReader.ReadObject();

​

        RSAParameters rsaParameters = isPrivate ?

            DotNetUtilities.ToRSAParameters((RsaPrivateCrtKeyParameters)(((AsymmetricCipherKeyPair)key).Private)) :

            DotNetUtilities.ToRSAParameters((RsaKeyParameters)key);

​

        RSACryptoServiceProvider rsaKey = new RSACryptoServiceProvider();

        rsaKey.ImportParameters(rsaParameters);

​

        return rsaKey;

    }

    public static AsymmetricKeyParameter GetAsymmetricKeyParameterFromPem(string pem, bool isPrivate)

    {

        PemReader pemReader = new PemReader(new StringReader(pem));

        object key = pemReader.ReadObject();

​

        return isPrivate ? ((AsymmetricCipherKeyPair)key).Private : (AsymmetricKeyParameter)key;

    }

}