RAGECOOP-V/Server/Security.cs

using System.IO;
using System.Net;
using System.Security.Cryptography;
using RageCoop.Core;

namespace RageCoop.Server;

internal class Security
{
    private readonly Logger Logger;
    private readonly Dictionary<IPEndPoint, Aes> SecuredConnections = new();
    public RSA RSA = RSA.Create(2048);

    public Security(Logger logger)
    {
        Logger = logger;
    }

    public bool HasSecuredConnection(IPEndPoint target)
    {
        return SecuredConnections.ContainsKey(target);
    }

    public byte[] Encrypt(byte[] data, IPEndPoint target)
    {
        var ms = new MemoryStream();
        using (var cs = new CryptoStream(ms, SecuredConnections[target].CreateEncryptor(), CryptoStreamMode.Write))
        {
            cs.Write(data, 0, data.Length);
        }

        return ms.ToArray();
    }

    public byte[] Decrypt(byte[] data, IPEndPoint target)
    {
        return new CryptoStream(new MemoryStream(data), SecuredConnections[target].CreateDecryptor(),
            CryptoStreamMode.Read).ReadToEnd();
    }

    public void AddConnection(IPEndPoint endpoint, byte[] cryptedKey, byte[] cryptedIV)
    {
        var key = RSA.Decrypt(cryptedKey, RSAEncryptionPadding.Pkcs1);
        var iv = RSA.Decrypt(cryptedIV, RSAEncryptionPadding.Pkcs1);
        // Logger?.Debug($"key:{key.Dump()}, iv:{iv.Dump()}");
        var conAes = Aes.Create();
        conAes.Key = key;
        conAes.IV = iv;
        if (!SecuredConnections.ContainsKey(endpoint))
            SecuredConnections.Add(endpoint, conAes);
        else
            SecuredConnections[endpoint] = conAes;
    }

    public void RemoveConnection(IPEndPoint ep)
    {
        if (SecuredConnections.ContainsKey(ep)) SecuredConnections.Remove(ep);
    }

    public void GetPublicKey(out byte[] modulus, out byte[] exponent)
    {
        var key = RSA.ExportParameters(false);
        modulus = key.Modulus;
        exponent = key.Exponent;
    }

    public void ClearConnections()
    {
        SecuredConnections.Clear();
    }
}