MLS (Message Layer Security) integration for the Offline Protocol SDK.

This crate provides end-to-end encryption using the MLS protocol via OpenMLS. It supports both 1:1 encrypted messaging and group messaging with forward secrecy and post-compromise security.

Architecture

The crate is designed with a storage-agnostic approach:

• Apps implement the [MlsStorage] trait for platform-native secure storage
• The [MlsManager] handles all MLS operations (key generation, encryption, decryption)
• Groups are used for both 1:1 sessions (2-person groups) and multi-party chats

Example

use offline_protocol_mls::{MlsManager, MlsStorage};

// Implement MlsStorage for your platform (iOS Keychain, Android Keystore, etc.)
let storage = MyPlatformStorage::new();

// Create the MLS manager
let manager = MlsManager::new("user123", Box::new(storage))?;

// Generate a key package to share with others
let key_package = manager.generate_key_package()?;

// Create a 1:1 session and send an encrypted message
let ciphertext = manager.encrypt_for_user("bob", b"Hello, Bob!")?;