nebulae.dotX25519 0.1.0

dotX25519

A high-performance, minimal, cross-platform wrapper around BoringSSL's X25519 key exchange implementation (RFC 7748).

The native backend is compiled directly from BoringSSL's curve25519 and related modules - ensuring constant-time cryptographic operations and production-grade optimizations across Windows, Linux, and macOS.

Tests are included and available in the Github repo.

Features

• Cross-platform: Works on Windows, Linux, and macOS (x64 & Apple Silicon).
• High performance: Optimized for speed, leveraging native SIMD-enabled code.
• Easy to use: Simple API for key exchange.
• Secure: Uses Google's BoringSSL implementation, which is widely trusted in the industry.
• Minimal dependencies: No external dependencies required (all are included), making it lightweight and easy to integrate.

Requirements

• .NET 8.0 or later
• Windows x64, Linux x64, or macOS (x64 & Apple Silicon)

Usage

using System;
using nebulae.dotX25519;

class Example
{
    static void Main()
    {
        Span<byte> alicePriv = stackalloc byte[32];
        Span<byte> bobPriv = stackalloc byte[32];
        Span<byte> alicePub = stackalloc byte[32];
        Span<byte> bobPub = stackalloc byte[32];
        Span<byte> sharedA = stackalloc byte[32];
        Span<byte> sharedB = stackalloc byte[32];

        // Generate two random private keys (e.g., from a CSPRNG)
        RandomNumberGenerator.Fill(alicePriv);
        RandomNumberGenerator.Fill(bobPriv);

        // Clamp per RFC 7748
        X25519.ClampPrivateKey(alicePriv);
        X25519.ClampPrivateKey(bobPriv);

        // Derive public keys
        X25519.DerivePublicKey(alicePriv, alicePub);
        X25519.DerivePublicKey(bobPriv, bobPub);

        // Derive shared secrets
        X25519.DeriveSharedSecret(alicePriv, bobPub, sharedA);
        X25519.DeriveSharedSecret(bobPriv, alicePub, sharedB);

        Console.WriteLine(sharedA.SequenceEqual(sharedB)
            ? "Shared secret matches"
            : "Mismatch!");
    }
}

Installation

You can install the package via NuGet:

$ dotnet add package nebulae.dotX25519

Or via git:

$ git clone https://github.com/nebulaeonline/dotX25519.git
$ cd dotEd25519
$ dotnet build

License

MIT

Roadmap

Unless there are vulnerabilities found, there are no plans to add any new features.