using System;

using Jose;

using System.Security.Cryptography;

using System.Text;

​

public class JweExample

{

    public static void Main()

    {

        bool useRandomKey = true;

        // Generate RSA keys

        using (var rsa = createRSA(useRandomKey))

        {

            // Payload to be encrypted

            var payload = new

            {

                acctNbr = "4097581122063621"

            };

​

            // Serialize payload to JSON

            string jsonPayload = Newtonsoft.Json.JsonConvert.SerializeObject(payload);

​

            // Encrypt the payload using RSA1_5 and AES_128_CBC_HMAC_SHA_256

            string jwe = Jose.JWT.Encode(jsonPayload, rsa, JweAlgorithm.RSA1_5, JweEncryption.A128CBC_HS256);

​

            // Output the JWE

            Console.WriteLine("Generated JWE:");

            Console.WriteLine(jwe);

​

            // Decrypt the JWE only if have Private Key

            if (useRandomKey)

            {

                string decryptedPayload = Jose.JWT.Decode(jwe, rsa);

​

                // Output the decrypted payload

                Console.WriteLine("Decrypted Payload:");

                Console.WriteLine(decryptedPayload);

                // Output the keys

                Console.WriteLine("Public Key: ");

                Console.Write(ExportPublicKeyToPem(rsa));

                Console.WriteLine("Private Key: ");

                Console.Write(ExportPrivateKeyToPem(rsa));

            }

        }

    }

    private static RSA createRSA(bool random)

    {

        var rsa = RSA.Create();

        if (random)

        {

            rsa = new RSACryptoServiceProvider(2048);

        }

        else

        {

            string publicKeyPem = @"

            -----BEGIN PUBLIC KEY-----

            MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEA/CJWWuvBi66UjwGYVkub

            8LehtdULhDT9wsC8DpPPvJvTes4S45zvJT8GAm5nS0goYkW8UUMIRC+g47NY40a9

            /bbtBLa9JhYkLyX/zEPvc/Z5u7Nmgup4LLA/0tV2CU50HHP4TBlUDOoQ/eU8XxfW

            cKzAsVH62e/rIuSCCCW5CP3Fx7nek+rhasKPTLPAXG46uNei85lM38RLp8v0q9BU

            jowfSfVQ5Ge+4d0unekMipLqz0j3c6faPbR2xmnBXmW8ET0CPQl+V4RZ/xNMZBFK

            ymcTySeYG5YrDhr6T3FaFpWTNZldxsVNyw5oDyYnH5jtmcdzuDeZUq5HzZo9VSXb

            cwIDAQAB

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

​

            // Import the public key from PEM

            rsa = PemReader.ImportPublicKey(publicKeyPem);

        }

        return rsa;

    }

    private static string ExportPublicKeyToPem(RSA rsa)

    {

        var sb = new StringBuilder();

        sb.AppendLine("-----BEGIN PUBLIC KEY-----");

        sb.AppendLine(Convert.ToBase64String(rsa.ExportSubjectPublicKeyInfo(), Base64FormattingOptions.InsertLineBreaks));

        sb.AppendLine("-----END PUBLIC KEY-----");

        return sb.ToString();

    }

​

    private static string ExportPrivateKeyToPem(RSA rsa)

    {

        var sb = new StringBuilder();

        sb.AppendLine("-----BEGIN PRIVATE KEY-----");

        sb.AppendLine(Convert.ToBase64String(rsa.ExportPkcs8PrivateKey(), Base64FormattingOptions.InsertLineBreaks));

        sb.AppendLine("-----END PRIVATE KEY-----");

        return sb.ToString();

    }

}

​

public class PemReader

{

    public static RSA ImportPublicKey(string pem)

    {

        var rsa = RSA.Create();

        var keyData = ReadPem(pem, "PUBLIC KEY");

        rsa.ImportSubjectPublicKeyInfo(keyData, out _);

        return rsa;

    }

​

    private static byte[] ReadPem(string pem, string section)

    {

        var header = $"-----BEGIN {section}-----";

        var footer = $"-----END {section}-----";

        var start = pem.IndexOf(header, StringComparison.Ordinal);

        var end = pem.IndexOf(footer, start, StringComparison.Ordinal);

        if (start < 0 || end < 0)

            throw new ArgumentException("PEM format is incorrect");

​

        start += header.Length;

        var base64 = pem[start..end].Replace("\r", "").Replace("\n", "").Replace(" ", "").Replace("\t", "");

        return Convert.FromBase64String(base64);

    }

}