Just a small app to parse pem files with bouncy castle

ParsePem.cs

// https://stackoverflow.com/questions/7149411/j2me-exception-when-casting-from-pemobject-to-asymmetrickeyparameter-with-bounc
// https://stackoverflow.com/questions/11506891/how-to-load-the-rsa-public-key-from-file-in-c-sharp
// https://stackoverflow.com/questions/11346200/reading-pem-rsa-public-key-only-using-bouncy-castle/11367152#11367152

using System;
using System.Buffers.Text;
using System.Collections.Generic;
using System.Diagnostics;
using System.Globalization;
using System.IO;
using System.Net;
using System.Net.Http;
using System.Numerics;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Digests;
using Org.BouncyCastle.Crypto.Encodings;
using Org.BouncyCastle.Crypto.Engines;
using Org.BouncyCastle.OpenSsl;
using Org.BouncyCastle.Security;


namespace TestConsole
{

    class Program
    {
        static void Main()
        {
            var keyPair = ReadAsymmetricKeyParameter("public.pem");

            var encryptEngine = new OaepEncoding(new RsaEngine(), new Sha512Digest());
            encryptEngine.Init(true,keyPair);

            var toEncrypt = Encoding.ASCII.GetBytes("Hello");

            var encrypt = encryptEngine.ProcessBlock(toEncrypt, 0, toEncrypt.Length);

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

            Console.ReadKey();
        }
        public static Org.BouncyCastle.Crypto.AsymmetricKeyParameter ReadAsymmetricKeyParameter(string pemFilename)
        {
            using (StreamReader reader = File.OpenText(pemFilename))
            {
                Org.BouncyCastle.OpenSsl.PemReader pr = 
                    new Org.BouncyCastle.OpenSsl.PemReader(reader);
                Org.BouncyCastle.Utilities.IO.Pem.PemObject po = pr.ReadPemObject();

                return PublicKeyFactory.CreateKey(po.Content);
            }
        }
    }
}