using System;

using PgpCore;

using System.Collections.Generic;

using System.IO;

​

public class Program

{   

    public static void Main()

    {

        // Bob is upgrading his key pair - we'd like a seamless transition      

        Console.Write("Generating keys...");

        using var keyGenerator = CloneKeyStreams().GetEnumerator();

        Console.WriteLine("DONE\n");

        string secretContentToEncrypt = "This is a super secret message!!!";

        Console.WriteLine("Secret message to send: {0}\n", secretContentToEncrypt);

        // Alice encrypts and signs content with both bobs new and old public keys...

        keyGenerator.MoveNext();

        var (alicePublicKey, alicePrivateKey, bobPublicKey, bobPrivateKey, bobNewPublicKey, bobNewPrivateKey) = keyGenerator.Current;

        EncryptionKeys encryptionKeys = new EncryptionKeys(new [] { bobPublicKey, bobNewPublicKey }, alicePrivateKey, "blah");

        PGP pgp = new PGP(encryptionKeys);      

        string encryptedSignedContent = pgp.EncryptArmoredStringAndSign(secretContentToEncrypt);

        Console.WriteLine("Encrypted and signed content from Alice:\n\n{0}", encryptedSignedContent);

        // Bob can decrypt with his old private key...

        keyGenerator.MoveNext();

        (alicePublicKey, alicePrivateKey, bobPublicKey, bobPrivateKey, bobNewPublicKey, bobNewPrivateKey) = keyGenerator.Current;       

        encryptionKeys = new EncryptionKeys(alicePublicKey, bobPrivateKey, "blah");

        pgp = new PGP(encryptionKeys);      

        var decryptedByBob = pgp.DecryptArmoredStringAndVerify(encryptedSignedContent);

        Console.WriteLine("Decrypted with bob's old key: {0}", decryptedByBob);

​

        // Bob can also decrypt with his new private key...

        keyGenerator.MoveNext();

        (alicePublicKey, alicePrivateKey, bobPublicKey, bobPrivateKey, bobNewPublicKey, bobNewPrivateKey) = keyGenerator.Current;

        encryptionKeys = new EncryptionKeys(alicePublicKey, bobNewPrivateKey, "blah");

        pgp = new PGP(encryptionKeys);

        var decryptedByBobNew = pgp.DecryptArmoredStringAndVerify(encryptedSignedContent);

        Console.WriteLine("Decrypted with bob's new key: {0}", decryptedByBob);     

        IEnumerable<(Stream apu, Stream apr, Stream bpu, Stream bpr, Stream bnpu, Stream bnpr)> CloneKeyStreams()

        {

            // Bob is upgrading his key pair - we'd like a seamless transition      

            using var alicePublicKey = new MemoryStream();

            using var alicePrivateKey = new MemoryStream();

            new PGP().GenerateKey(alicePublicKey, alicePrivateKey, "foo", "blah");

​

            using var bobPublicKey = new MemoryStream();

            using var bobPrivateKey = new MemoryStream();

            new PGP().GenerateKey(bobPublicKey, bobPrivateKey, "foo", "blah");

​

            using var bobNewPublicKey = new MemoryStream();

            using var bobNewPrivateKey = new MemoryStream();

            new PGP().GenerateKey(bobNewPublicKey, bobNewPrivateKey, "foo", "blah");

            while (true)

            {

                ResetPositions(alicePublicKey, alicePrivateKey, bobPublicKey, bobPrivateKey, bobNewPublicKey, bobNewPrivateKey);

​

                var apu = new MemoryStream();

                var apr = new MemoryStream();

                var bpu = new MemoryStream();

                var bpr = new MemoryStream();

                var bnpu = new MemoryStream();

                var bnpr = new MemoryStream();

​

                alicePublicKey.CopyTo(apu);

                alicePrivateKey.CopyTo(apr);

                bobPublicKey.CopyTo(bpu);

                bobPrivateKey.CopyTo(bpr);

                bobNewPublicKey.CopyTo(bnpu);

                bobNewPrivateKey.CopyTo(bnpr);

​

                ResetPositions(apu, apr, bpu, bpr, bnpu, bnpr);

​

                yield return (apu, apr, bpu, bpr, bnpu, bnpr);

            }

        }

        void ResetPositions(params Stream[] args)

        {

            foreach(var s in args) s.Position = 0;

        }

    }

​

}