using System;
using System.Linq;
using Org.BouncyCastle.Asn1.X9;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.Crypto.Generators;
using Org.BouncyCastle.Crypto.Parameters;
using Org.BouncyCastle.Security;

namespace Program
{
    class Program
    {
        static void Main(string[] args)
        {
            GenerateKeyPair();
        }

        static AsymmetricCipherKeyPair GenerateKeyPair()
        {
            var curve = ECNamedCurveTable.GetByName("secp256k1");
            var domainParams = new ECDomainParameters(curve.Curve, curve.G, curve.N, curve.H, curve.GetSeed());

            var secureRandom = new SecureRandom();
            var keyParams = new ECKeyGenerationParameters(domainParams, secureRandom);

            var generator = new ECKeyPairGenerator("ECDSA");
            generator.Init(keyParams);
            var keyPair = generator.GenerateKeyPair();

            var privateKey = keyPair.Private as ECPrivateKeyParameters;
            var publicKey = keyPair.Public as ECPublicKeyParameters;

            Console.WriteLine($"Private key: {ToHex(privateKey.D.ToByteArrayUnsigned())}");
            Console.WriteLine($"Public key: {ToHex(publicKey.Q.GetEncoded())}");

            return keyPair;
        }

        static string ToHex(byte[] data) => String.Concat(data.Select(x => x.ToString("x2")));
    }
}