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✅ This repository is public and intended for all developers, researchers, and enthusiasts interested in private and secure communications.

MTProtocol is an open, highly secure implementation of the Double Ratchet protocol in C, designed as the cryptographic foundation for the anonymous P2P messenger Mesh.

The project focuses on:

• Full control over data: all encryption and key management operations occur locally.
• Maximum resilience to compromise: forward secrecy and post-compromise security by default.
• Transparency and auditability: open source code allows for independent security verification.

Technology stack:

• C99 — for the cryptographic core and memory management
• OpenSSL 3.0+ — for X25519, HKDF, ChaCha20-Poly1305
• Python 3.6+ — for auxiliary tools: build (meshprotocol.py), testing, and debugging

This protocol is not just a library. It is a privacy guarantee built on the principles of openness and trust through verifiability.

MeshRatchet is a lightweight C library implementing a secure cryptographic messaging protocol with double ratcheting (forward secrecy) and post-compromise security. The library is designed for use in instant messaging apps, IoT devices, and other applications where confidentiality and integrity of communications are important.

Version: v0.1 Author: NorthernHush

• Double Ratchet: Automatic key updates with each message.
• Forward Secrecy: Compromising a long-term key does not reveal past messages.
• Post-Compromise Security: Even if current keys are leaked, the session regains security over time. - Integrity and Authentication: Authenticated encryption (AEAD) via ChaCha20-Poly1305.
• Flexible Configuration: Configure message size, key refresh intervals, logging, and random number generation.
• Secure Memory Wipe: Sensitive data (keys, secrets) are cleared after use.
• Serialization and Batch Operations (optional).

• OpenSSL 3.0+ (for X25519, HKDF, ChaCha20-Poly1305)
• Python 3.6+
• C99 compiler or later
• POSIX-compliant system (for time())

MeshRatchet comes with a convenient Python script, meshprotocol.py, which automates building the library and examples.

• Python 3.6+
• OpenSSL 3.0+ (with header files)
• C compiler (gcc/clang)

# Building the main library
python3 meshprotocol.py build

# Building with examples
python3 meshprotocol.py build --with-examples

# Installing on the system (optional)
sudo python3 meshprotocol.py install

# Checking dependencies
python3 meshprotocol.py check

# Running tests (if any)
python3 meshprotocol.py test

# Generating documentation
python3 meshprotocol.py docs

# Cleaning up build artifacts
python3 meshprotocol.py clean

💡 The script will automatically detect OpenSSL and set the compilation flags. If necessary, you can specify the path manually: python3 meshprotocol.py build --openssl-path /usr/local/ssl

MeshRatchet is built on proven and modern cryptographic algorithms:

| Component | Algorithm | Purpose | |---------------------|-----------------------------------------------| | Key Exchange | X25519 (Elliptic Curve DH) | Secure Shared Secret Negotiation | | Derivative Function | HKDF-SHA256 | Generate Cryptographic Keys from Secrets | | Encryption | ChaCha20-Poly1305 (AEAD) | Authenticated Message Encryption | | Ratchet Function | HMAC-SHA256 | One-Way Keychain Update |

All primitives comply with IETF and Signal Protocol recommendations.

The library provides a simple and secure C API:

• mr_init() / mr_init_ex() Initialize a context with default settings or user-defined parameters.

• mr_generate_key_pair() Generate a new X25519 key pair (public + private key).

• mr_session_create() Establish a secure session with the remote party based on public key exchange.

• mr_encrypt() / mr_decrypt() Encrypt and decrypt messages with automatic key management and replay protection.

• mr_key_update() Scheduled key updates (e.g., once every N messages).

• mr_emergency_key_update() Emergency reset of all keys if a compromise is suspected.

• mr_get_session_info() Retrieving session metadata: counters, ID, activity status.

• mr_error_string() Converting error codes to human-readable strings for logging and debugging.

📌 A full description of types, structures, and return values ​​is in the meshratchet.h header file.

MTProtocol is distributed under the proprietary MIT LICENSE.

• ✅ Free for research, education, and non-commercial use.
• 💼 Written permission required for commercial implementation.

We are open to collaboration and ready to help:

• Vulnerability reports: send them to Telegram with the subject [SECURITY]

⚠️ Important: MTProtocol v0.1 is an alpha version, under active development. Not recommended for use in production environments without independent cryptographic auditing.