ShadowLink - Secure Local Encrypted Tunnel

ShadowLink is a next-generation local VPN and secure tunnel application that uses ChaCha20-Poly1305 and X25519 key exchange (the cryptographic primitives of WireGuard) to encrypt traffic. It comes with both a Command Line Interface (CLI) and a Native GUI (via PyQt6) for optimal performance and integration.

🚀 Features

• Double Encryption: Traffic is encrypted locally using ephemeral keys before leaving your device.
• DPI Bypass (Obfuscation): Evades Deep Packet Inspection (DPI) on strict university/corporate networks via Fake HTTP handshakes and payload masking.
• Full UDP Support: Tunnels UDP datagrams (e.g., for VoIP and online gaming) over the secure TCP obfuscation layer via SOCKS5 UDP Associate.
• Strict Mode (Kill Switch): Automatically cuts traffic if the secure tunnel drops.
• System-Wide Proxy: Routes all system traffic through the secure tunnel with one click.
• Modern UI: Clean native Windows GUI with real-time stats (PyQt6).
• Cross-Platform: Built natively with Python.

🛠 Architecture

ShadowLink now uses a fully native Python architecture:

• Core Backend: src/api.py, handling specific encryption, connection tunnels, and socket operations.
• CLI Frontend: src/cli.py, a lightweight command line application.
• GUI Frontend: src/gui.py, a native Windows desktop GUI using PyQt6.

❓ What Makes It Different?

Feature	Standard SOCKS5 Proxy	ShadowLink
Encryption	None (Usually plaintext)	ChaCha20-Poly1305 (WireGuard)
Key Management	Static Password / None	Ephemeral X25519 (New key per session)
Purpose	IP Masking	DPI Obfuscation & Layered Security
Dependency	Remote Server	Local-Only (Server runs on your localhost)

Why use this locally? It isolates your application traffic from the rest of the OS until it is fully encrypted. Even if malware on your PC packet-sniffs your network card, they only see the encrypted ShadowLink traffic, not the raw application data.

⚠️ Limitations

1. Performance Overhead: Double encryption (ShadowLink + ProtonVPN) adds a small amount of latency and CPU overhead.
2. Manual Proxy Config: You must configure your browser/app to use the provided SOCKS5 proxy if not using System-Wide mode.

📦 Installation & Usage

Prerequisites

• Python 3.10+

1. Setup

# Install Python dependencies
pip install -r requirements.txt

2. Run CLI Version

For a lightweight, terminal-based experience:

python src/cli.py

3. Run GUI Version

For a fully native Windows desktop graphical interface:

python src/gui.py

🔐 Verification

To verify the encryption implementation (X25519 + ChaCha20-Poly1305), run the included verification script

python src/verify_encryption.py

This script simulates a full handshake and encryption cycle, printing the keys and ciphertext to the console for inspection.

📄 License

MIT