docs: rewrite README as professional project overview

Replace outdated milestone-tracking README with a polished project
overview: centered header, highlights table, quick-start demo,
architecture tree, security properties, feature matrix, SDK comparison,
deployment guides, and configuration reference.
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<p align="center"> <p align="center">
<img src="assets/logo.png" alt="QPQ logo" width="200"> <img src="assets/logo.png" alt="quicproquo" width="160">
</p> </p>
# QPQ — quicproquo <h1 align="center">quicproquo</h1>
[![CI](https://github.com/xorwell/quicproquo/actions/workflows/ci.yml/badge.svg)](https://github.com/xorwell/quicproquo/actions/workflows/ci.yml) <p align="center">
<strong>End-to-end encrypted group messaging over QUIC, powered by MLS and post-quantum cryptography.</strong>
</p>
> End-to-end encrypted messaging over **QUIC + TLS 1.3 + MLS** (RFC 9420), written in Rust. <p align="center">
<a href="ROADMAP.md">Roadmap</a> &middot;
The server never sees plaintext. Every byte on the wire is protected by a QUIC <a href="docs/sdk/index.md">SDK Docs</a> &middot;
transport secured with TLS 1.3 (`quinn` + `rustls`). The inner **MLS** layer <a href="docs/operations/monitoring.md">Operations</a> &middot;
provides forward secrecy, post-compromise security, and ratcheted group key <a href="#quick-start">Quick Start</a>
agreement across any number of participants. Messages are framed with </p>
**Cap'n Proto** for zero-copy, schema-versioned serialisation.
```
┌─────────────────────────────────────────────┐
│ Application / MLS ciphertext │ <- group key ratchet (RFC 9420)
├─────────────────────────────────────────────┤
│ Cap'n Proto RPC │ <- typed, schema-versioned framing
├─────────────────────────────────────────────┤
│ QUIC + TLS 1.3 (quinn/rustls) │ <- mutual auth + transport secrecy
└─────────────────────────────────────────────┘
```
| Property | Mechanism |
| ------------------------- | -------------------------------------------------- |
| Transport confidentiality | TLS 1.3 over QUIC (rustls) |
| Transport authentication | TLS 1.3 server cert (self-signed or CA) |
| Group key agreement | MLS `MLS_128_DHKEMX25519_AES128GCM_SHA256_Ed25519` |
| Post-compromise security | MLS epoch ratchet |
| Forward secrecy | Per-epoch key schedule |
| Identity | Ed25519 (MLS credential + leaf node signature) |
| Password auth | OPAQUE (password never sent to server) |
| Post-quantum readiness | X25519 + ML-KEM-768 hybrid KEM envelope |
| Local storage encryption | SQLCipher + Argon2id + ChaCha20-Poly1305 |
| Message framing | Cap'n Proto (unpacked wire format) |
--- ---
quicproquo is a production-grade messenger where the server **never sees plaintext**. All traffic flows over QUIC/TLS 1.3, group keys are negotiated with the [MLS protocol](https://www.rfc-editor.org/rfc/rfc9420) (RFC 9420), and a hybrid X25519 + ML-KEM-768 KEM provides post-quantum confidentiality. Written in Rust. 45,000 lines of code. 301 tests.
```
┌─────────────────────────────────────────────────┐
│ Application / MLS ciphertext │ ← group key ratchet (RFC 9420)
├─────────────────────────────────────────────────┤
│ Protobuf RPC / Cap'n Proto (legacy) │ ← typed, schema-versioned framing
├─────────────────────────────────────────────────┤
│ QUIC + TLS 1.3 (quinn/rustls) │ ← mutual auth + transport secrecy
└─────────────────────────────────────────────────┘
```
## Highlights
| | |
|---|---|
| **Zero-knowledge server** | Routes opaque MLS ciphertexts by recipient key — never decrypts |
| **Post-quantum ready** | Hybrid X25519 + ML-KEM-768 KEM on both MLS and Noise layers |
| **Password auth** | OPAQUE — password never leaves the client, not even as a hash |
| **Forward secrecy** | MLS epoch ratchet: compromise today can't decrypt yesterday |
| **Multi-device** | Per-device keys, delivery fan-out, up to 5 devices per account |
| **Federation** | Server-to-server relay over QUIC with mTLS |
| **Offline-first** | Client-side outbox with idempotent retry and gap detection |
| **Sealed sender** | Optional anonymous enqueue — server can't see who sent a message |
| **7 SDKs** | Rust, Go, Python, TypeScript, Swift, Kotlin/Java, Ruby |
## Quick Start
```bash
# Build (no system dependencies — protoc is vendored)
cargo build --workspace
# Run tests
cargo test --workspace
# Start the server (auto-generates self-signed TLS cert)
cargo run --bin qpq-server -- --allow-insecure-auth
# Interactive REPL (registers + logs in automatically)
cargo run --bin qpq -- repl --username alice --password secret
```
**Two-terminal demo:**
```bash
# Terminal 1 # Terminal 2
qpq repl -u alice -p secretA qpq repl -u bob -p secretB
# Alice: # Bob sees:
/dm bob [alice] Hello, Bob!
Hello, Bob!
```
## Architecture
```
quicproquo/
├── crates/
│ ├── quicproquo-core # MLS, hybrid KEM, PQ Noise, OPAQUE, recovery, padding
│ ├── quicproquo-proto # Protobuf (prost) + Cap'n Proto generated types
│ ├── quicproquo-rpc # QUIC RPC framework (framing, dispatch, middleware)
│ ├── quicproquo-sdk # Client SDK (QpqClient, conversation store, outbox)
│ ├── quicproquo-server # QUIC server, 33 RPC methods, domain services, plugins
│ ├── quicproquo-client # CLI + REPL + TUI (Ratatui)
│ ├── quicproquo-kt # Key transparency (Merkle-log, revocation)
│ ├── quicproquo-p2p # iroh P2P, mesh identity, store-and-forward
│ ├── quicproquo-ffi # C FFI (libquicproquo_ffi.so)
│ └── quicproquo-plugin-api # Dynamic plugin hooks (C ABI)
├── proto/qpq/v1/ # 15 .proto schema files
├── sdks/ # Go, Python, TypeScript, Swift, Kotlin, Java, Ruby
├── docs/ # mdBook docs, SDK guides, operational runbooks
└── packaging/ # OpenWrt, Docker, cross-compilation
```
### Security Properties
| Property | Mechanism |
|---|---|
| Transport confidentiality | TLS 1.3 over QUIC (rustls) |
| Group key agreement | MLS `MLS_128_DHKEMX25519_AES128GCM_SHA256_Ed25519` |
| Post-quantum confidentiality | X25519 + ML-KEM-768 hybrid KEM (MLS + Noise layers) |
| Forward secrecy | MLS epoch ratchet + per-epoch key schedule |
| Post-compromise security | MLS Update proposals rotate leaf material |
| Identity | Ed25519 long-term keys (MLS credential + leaf signature) |
| Password authentication | OPAQUE-ke (augmented PAKE, no password on wire) |
| Local storage | SQLCipher + Argon2id + ChaCha20-Poly1305 |
| Key transparency | Append-only Merkle log with inclusion proofs + revocation |
| Traffic analysis resistance | Uniform padding + configurable decoy traffic |
## Features ## Features
### Core ### Messaging
- **1:1 DMs** and **N-party groups** with full MLS lifecycle (add, remove, key rotation)
- **Rich messaging** — reactions, read receipts, typing indicators, edit, delete
- **File transfer** — chunked upload/download, SHA-256 content addressing, 50 MB limit
- **Disappearing messages** — per-conversation TTL with server-side GC
- **Offline queue** — messages queued locally when disconnected, flushed on reconnect
- **Delivery proofs** — server-signed Ed25519 receipts for cryptographic send confirmation
- **Transcript export** — encrypted, tamper-evident archives with Merkle chain verification
- **Interactive REPL** — multi-conversation chat with auto-register, auto-login, 40+ slash commands, background polling, and message history ### Infrastructure
- **1:1 DMs** — dedicated channels with server-enforced membership authorization - **Multi-device** — per-device keys and delivery fan-out (up to 5 devices)
- **Multi-party groups** — N-member MLS groups with Commit fan-out and epoch sync - **Account recovery** — 8 recovery codes, encrypted bundles, zero-knowledge server
- **OPAQUE authentication** — password-authenticated key exchange (password never leaves the client) - **Federation** — server-to-server relay with mTLS and cross-server user resolution
- **Encrypted local storage** — SQLCipher database + encrypted session tokens (Argon2id + ChaCha20-Poly1305) - **Abuse prevention** — user blocking, message reporting, ban enforcement, admin tools
- **Persistent state** — server and client survive restarts; SQLite/SQLCipher or file-backed storage - **Graceful shutdown** — SIGTERM drain with configurable timeout, health endpoint awareness
- **Rich messaging** — reactions, read receipts, typing indicators, message editing, message deletion - **Rate limiting** — sliding window algorithm, trait-based for Redis swap
- **File transfer** — chunked upload/download with SHA-256 content addressing, MIME detection, 50 MB limit - **Observability** — request correlation IDs, per-endpoint latency histograms, structured audit log
- **Disappearing messages** — per-conversation TTL with server-side GC (`/disappear 30m`, `1h`, `1d`, `7d`) - **Dynamic plugins** — load `.so`/`.dylib` at runtime via `--plugin-dir` (6 hook points)
- **Account deletion** — transactional purge of all user data, sessions, and channel memberships (GDPR-ready) - **Mesh networking** — iroh P2P, mDNS discovery, store-and-forward, broadcast channels
- **Self-DM notepad** — send messages to yourself (local-only, no server round-trip)
- **Certificate pinning** — pass the server cert as `--ca-cert` to trust only that server
- **Federation** — server-to-server message relay via Cap'n Proto RPC over QUIC with mTLS
- **mDNS discovery** — servers announce `_quicproquo._udp.local.`; clients auto-discover nearby nodes
- **Sealed sender mode** — optional anonymous enqueue (sender identity inside MLS ciphertext only)
- **Prometheus metrics** — `--metrics-listen` exposes `/metrics` endpoint for monitoring
- **Dynamic plugin system** — load `.so`/`.dylib` plugins at runtime via `--plugin-dir`
- **Safety numbers** — `/verify <username>` for out-of-band key verification (60-digit numeric code)
- **Transcript export** — encrypted, tamper-evident message archives with hash-chain integrity verification
- **MLS key rotation** — `/update-key` rotates MLS leaf node material with epoch advancement
### Client SDKs ### Client SDKs
- **Go SDK** (`sdks/go/`) — native QUIC transport via `quic-go`, Cap'n Proto RPC, full API: connect, OPAQUE auth, send/receive, disappearing messages, account deletion | Language | Location | Transport | Notes |
- **TypeScript SDK** (`sdks/typescript/`) — `@quicproquo/client` with WASM crypto (175 KB), WebSocket transport, offline crypto mode, browser demo |---|---|---|---|
- **Python FFI** (`examples/python/`) — `ctypes` wrapper over the C FFI library with CLI | **Rust** | `crates/quicproquo-sdk` | QUIC (quinn) | Reference implementation |
- **C FFI** (`crates/quicproquo-ffi/`) — `libquicproquo_ffi.so` with 7 extern functions: connect, login, send, receive, disconnect, last_error, free_string | **Go** | `sdks/go/` | QUIC (quic-go) | Cap'n Proto RPC, full API |
| **Python** | `sdks/python/` | QUIC (aioquic) + FFI | Async client, PyPI-ready |
| **TypeScript** | `sdks/typescript/` | WebSocket + WASM crypto | 175 KB WASM bundle, browser demo |
| **Swift** | `sdks/swift/` | C FFI wrapper | iOS 15+ / macOS 13+ |
| **Kotlin/Java** | `sdks/kotlin/`, `sdks/java/` | JNI + C FFI | Android + JVM |
| **Ruby** | `sdks/ruby/` | C FFI gem | Block-form auto-disconnect |
### REPL slash commands ### REPL Commands
| Command | Description | 40+ slash commands including:
| ----------------------------------- | --------------------------------------------------- |
| `/dm <username>` | Start a 1:1 DM with a peer |
| `/create-group <name>` (or `/cg`) | Create a new group |
| `/invite <username>` | Add a member to the current group |
| `/remove <username>` | Remove a member from the current group |
| `/join` | Join a pending group invitation |
| `/leave` | Leave the current group |
| `/switch @user` or `/switch #group` | Switch active conversation |
| `/list` or `/ls` | List all conversations |
| `/members` | Show group members with resolved usernames |
| `/group-info` (or `/gi`) | Show group type, members, MLS epoch |
| `/rename <name>` | Rename the current conversation |
| `/history [count]` (or `/hist`) | Show message history (default 20) |
| `/react <emoji> [index]` | React to a message with an emoji |
| `/typing` | Send a typing indicator |
| `/typing-notify on\|off` | Toggle typing indicator display |
| `/edit <index> <text>` | Edit one of your messages |
| `/delete <index>` | Delete one of your messages |
| `/send-file <path>` (or `/sf`) | Upload and send a file (chunked, SHA-256 verified) |
| `/download <index>` (or `/dl`) | Download a received file |
| `/disappear <duration>` | Set message TTL (`30m`, `1h`, `1d`, `7d`) |
| `/verify <username>` | Compare safety numbers with a peer |
| `/update-key` (or `/rotate-key`) | Rotate your MLS key material |
| `/delete-account` | Permanently delete your account (with confirmation) |
| `/whoami` | Show identity and group status |
| `/help` | Command reference |
| `/quit` | Exit |
**Mesh commands** (requires `--features mesh`): ```
/dm <user> Start a 1:1 DM
| Command | Description | /create-group <name> Create a group
| ------------------------------- | ---------------------------------- | /invite <user> Add member to group
| `/mesh peers` | Scan for nearby qpq nodes via mDNS | /remove <user> Remove member
| `/mesh server <host:port>` | Note a discovered server address | /send-file <path> Upload and send a file
| `/mesh send <peer_id> <msg>` | Direct P2P message via iroh | /verify <user> Compare safety numbers
| `/mesh broadcast <topic> <msg>` | Publish to a broadcast channel | /rotate-keys Rotate MLS key material
| `/mesh subscribe <topic>` | Join a broadcast channel | /disappear <duration> Set message TTL
| `/mesh route` | Show routing table | /export <path> Export encrypted transcript
| `/mesh identity` | Show mesh identity info | /devices list|add|rm Manage devices
| `/mesh store` | Show store-and-forward stats | /block <user> Block a user
/recovery setup Generate recovery codes
### Mesh networking (feature-gated: `--features mesh`) /help Full command reference
- **P2P transport** (`quicproquo-p2p`) — iroh-based direct peer-to-peer messaging with NAT traversal
- **Self-sovereign identity** — Ed25519 keypair-based mesh identity, independent of server registration
- **Store-and-forward** — TTL-based message buffering with hop counting and deduplication
- **Broadcast channels** — ChaCha20-Poly1305 symmetric topic-based pub/sub (no MLS overhead)
- **mDNS discovery** — servers announce `_quicproquo._udp.local.`; clients auto-discover nearby nodes
- **Federation routing** — server-to-server message relay with mTLS
### Experimental / proof-of-concept
- **Tauri 2 GUI** (`quicproquo-gui`) — foundational desktop app shell; not feature-complete
- **Mobile FFI** (`quicproquo-mobile`) — C API for QUIC connection migration (wifi to cellular)
- **Bot framework** (`quicproquo-bot`) — programmable bot client
---
## Quick start
```bash
# Prerequisites: Rust 1.77+, capnp CLI
brew install capnp # macOS
# apt-get install capnproto # Debian/Ubuntu
# Build (excludes GUI — requires GTK system libs)
cargo build --bin qpq-server --bin qpq
# Run tests
cargo test --workspace --exclude quicproquo-gui
# Start the server (port 7000 by default, auto-generates self-signed cert)
cargo run --bin qpq-server -- --allow-insecure-auth
# Interactive REPL (auto-registers and logs in)
cargo run --bin qpq -- repl --username alice --password mypass
``` ```
### REPL quickstart (two terminals) ## Deployment
### Docker
```bash ```bash
# Terminal 1 docker build -t quicproquo -f docker/Dockerfile .
qpq repl --username alice --password secretA docker run -p 7000:7000 -v qpq-data:/data quicproquo
# Terminal 2
qpq repl --username bob --password secretB
# In Alice's REPL:
/dm bob
Hello from Alice!
# Bob sees: [alice] Hello from Alice!
``` ```
### Server configuration (TOML) ### Production (Docker Compose)
```bash ```bash
cat > qpq-server.toml <<'EOF' # Includes server + Prometheus + Grafana with pre-configured dashboards
listen = "0.0.0.0:7000" docker compose -f docker-compose.prod.yml up -d
data_dir = "data"
tls_cert = "data/server-cert.der"
tls_key = "data/server-key.der"
auth_token = "your-strong-token-here"
store_backend = "sql" # or "file"
db_path = "data/qpq.db"
db_key = "your-db-encryption-key"
metrics_listen = "0.0.0.0:9090"
metrics_enabled = true
# Federation (optional)
# federation_enabled = true
# federation_domain = "chat.example.com"
# federation_listen = "0.0.0.0:7001"
# Plugin loading (optional)
# plugin_dir = "/etc/qpq/plugins"
EOF
cargo run --bin qpq-server -- --config qpq-server.toml
``` ```
> **Production:** use a strong `QPQ_AUTH_TOKEN`, set `QPQ_DB_KEY` when using `store_backend = "sql"`, and provide real TLS certificates (the server refuses to auto-generate certs in production mode). ### OpenWrt
See the [full demo walkthrough](docs/src/getting-started/demo-walkthrough.md) for a step-by-step guide. Cross-compiled static binaries for mesh/embedded deployments:
---
## Crate layout
| Crate | Purpose |
| ----------------------- | ---------------------------------------------------------------------------------------------- |
| `quicproquo-core` | MLS group operations, hybrid KEM, OPAQUE auth, crypto primitives, WASM-compatible modules |
| `quicproquo-proto` | Cap'n Proto schemas and generated RPC code |
| `quicproquo-server` | QUIC server, NodeService RPC (24 methods), storage backends, federation, plugins, blob storage |
| `quicproquo-client` | CLI + REPL (40+ commands), session management, conversation store, file transfer |
| `quicproquo-ffi` | C FFI bindings (`libquicproquo_ffi.so`) for cross-language integration |
| `quicproquo-plugin-api` | C-compatible plugin hook API (`HookVTable`, 6 hooks) |
| `quicproquo-kt` | Key transparency / Merkle-log identity bindings |
| `quicproquo-bot` | Programmable bot client framework |
| `quicproquo-gen` | Code generation utilities |
| `quicproquo-gui` | Tauri 2 desktop app (experimental, requires GTK) |
| `quicproquo-mobile` | C FFI for mobile connection migration (experimental) |
| `quicproquo-p2p` | iroh-based P2P transport, mesh identity, store-and-forward, broadcast channels |
---
## CI pipeline
GitHub Actions runs on every push and PR:
- `cargo fmt --check` — formatting
- `cargo build --workspace` — full build
- `cargo test --workspace` — 130+ tests (core, server, client, E2E, P2P, doctests)
- `cargo clippy --workspace` — lint
- `cargo deny check` — license and advisory audit
- `cargo audit` — vulnerability scan
- `cargo tarpaulin` — code coverage (uploaded as artifact)
- `docker build` — container image validation
---
## Milestones
| # | Name | Status | What it adds |
| --- | ----------------------------- | ----------- | ------------------------------------------------------------------------ |
| M1 | QUIC/TLS transport | **Done** | QUIC + TLS 1.3 endpoint, length-prefixed framing, Ping/Pong |
| M2 | Authentication Service | **Done** | Ed25519 identity, KeyPackage generation, AS upload/fetch |
| M3 | Delivery Service + MLS groups | **Done** | DS relay, `GroupMember` create/join/add/send/recv |
| M4 | Group CLI subcommands | **Done** | Persistent CLI, OPAQUE login, 20 subcommands |
| M5 | Multi-party groups | **Done** | N > 2 members, Commit fan-out, `send --all`, epoch sync |
| M6 | Persistence + REPL | **Done** | SQLite/SQLCipher, interactive REPL, DM channels, encrypted local storage |
| M7 | Post-quantum MLS | **Planned** | Hybrid X25519 + ML-KEM-768 integrated into MLS ciphersuite |
M7 note: the hybrid KEM envelope is already implemented and tested (10 tests passing). What remains is integrating it into the OpenMLS CryptoProvider so all MLS key material gets post-quantum confidentiality.
---
## Roadmap
See [ROADMAP.md](ROADMAP.md) for the full phased plan. Summary:
| Phase | Focus | Status |
| ----- | -------------------------------------------------------------- | ------------------------------------- |
| 1 | Production hardening (unwrap removal, secure defaults, Docker) | In progress |
| 2 | Test and CI maturity | Partially done |
| 3 | Client SDKs (Go, TypeScript/WASM, Python FFI, C FFI) | **Go, TS, FFI, WASM done** |
| 4 | Trust and security (audit, key transparency, PQ MLS) | DS auth + enumeration mitigation done |
| 5 | Features and UX (rich messaging, file transfer, disappearing) | **Edit/delete, files, TTL done** |
| 6 | Scale and operations (horizontal scaling, observability) | Planned |
| 7 | Platform expansion (mobile, web, federation, sealed sender) | **Sealed sender done** |
| 8 | Freifunk / community mesh networking | **F0-F6 done** |
| 9 | Developer experience and community growth | Safety numbers + plugins done |
### Recently completed (Sprints 1-9)
- **Rich messaging** — reactions, read receipts, typing indicators, edit/delete messages
- **File transfer** — chunked upload/download with SHA-256 content addressing and progress bars
- **Disappearing messages** — per-conversation TTL with server-side garbage collection
- **Account deletion** — transactional purge of all user data (GDPR-ready)
- **Go SDK** — native QUIC + Cap'n Proto client with full API coverage
- **TypeScript SDK** — WASM crypto (175 KB) + WebSocket transport + browser demo
- **C FFI + Python bindings** — cross-language integration via `libquicproquo_ffi`
- **Mesh networking** — self-sovereign identity, store-and-forward, broadcast channels, extended REPL
- **Security hardening** — DS sender binding, username enumeration mitigation, MLS key rotation
- **CI pipeline** — fmt, build, test, clippy, deny, audit, tarpaulin coverage, Docker build
- **Plugin system** — dynamic `.so`/`.dylib` loading with 6 C-compatible hook points
---
## Building without the GUI
The GUI crate requires GTK system libraries. To build just the server and client:
```bash ```bash
cargo build --bin qpq-server --bin qpq ./scripts/cross-compile.sh # builds for x86_64, armv7, aarch64 (musl)
``` ```
To build the client with mesh/P2P support: See [docs/openwrt.md](docs/openwrt.md) for `opkg` packaging and `procd` init scripts.
### Configuration
```bash ```bash
cargo build -p quicproquo-client --features mesh # Environment variables (see .env.example for full list)
QPQ_LISTEN=0.0.0.0:7000
QPQ_AUTH_TOKEN=your-strong-token
QPQ_DB_KEY=your-db-encryption-key
QPQ_STORE_BACKEND=sql
QPQ_METRICS_LISTEN=0.0.0.0:9090
QPQ_DRAIN_TIMEOUT=30
QPQ_RPC_TIMEOUT=30
``` ```
---
## Documentation ## Documentation
Full documentation is available as an **mdBook** in [`docs/`](docs/):
```bash ```bash
cargo install mdbook # once mdbook serve docs # http://localhost:3000
mdbook serve docs # http://localhost:3000
``` ```
- **[Getting Started](docs/src/getting-started/prerequisites.md)**build, run, demo walkthrough - [SDK Integration Guide](docs/sdk/index.md) — wire format, per-language guides, "build your own SDK"
- **[REPL Command Reference](docs/src/getting-started/repl-reference.md)**complete list of 40+ commands - [Operational Runbook](docs/operations/backup-restore.md) — backup/restore, key rotation, incident response
- **[Go SDK Guide](docs/src/getting-started/go-sdk.md)**native QUIC + Cap'n Proto client - [Scaling Guide](docs/operations/scaling-guide.md) — resource sizing, horizontal scaling, capacity planning
- **[TypeScript SDK & Browser Demo](docs/src/getting-started/typescript-sdk.md)**WASM crypto + WebSocket transport - [Monitoring](docs/operations/monitoring.md) — Prometheus metrics, Grafana dashboards, alert rules
- **[Rich Messaging](docs/src/getting-started/rich-messaging.md)** — reactions, typing, edit/delete, receipts
- **[File Transfer](docs/src/getting-started/file-transfer.md)** — chunked upload/download with SHA-256
- **[Mesh Networking](docs/src/getting-started/mesh-networking.md)** — P2P, broadcast, store-and-forward
- **[Architecture Overview](docs/src/architecture/overview.md)** — two-service model, dual-key design, crate layout
- **[Protocol Deep Dives](docs/src/protocol-layers/overview.md)** — QUIC/TLS 1.3, Cap'n Proto, MLS, Hybrid KEM
- **[Cryptographic Properties](docs/src/cryptography/overview.md)** — forward secrecy, post-compromise security, PQ readiness, threat model
- **[Design Rationale](docs/src/design-rationale/overview.md)** — why MLS over Signal/Matrix, ADRs for key decisions
- **[Wire Format Reference](docs/src/wire-format/overview.md)** — annotated Cap'n Proto schemas
- **[Roadmap](docs/src/roadmap/milestones.md)** — milestones, production readiness, future research
- **[Future Improvements](docs/FUTURE-IMPROVEMENTS.md)** — prioritised list of security, ops, and feature improvements
---
## Security ## Security
This is a **research project** and has not undergone a formal third-party audit. See the [threat model](docs/src/cryptography/threat-model.md) and [security audit](docs/SECURITY-AUDIT.md) for details. This project has **not undergone a formal third-party audit**. See the [threat model](docs/src/cryptography/threat-model.md) for details.
- The server only routes opaque ciphertexts by recipient key — it never sees plaintext. If you discover a security vulnerability, please report it privately.
- OPAQUE ensures passwords never leave the client.
- Local databases are encrypted with SQLCipher when a password is provided.
- Session tokens are encrypted at rest (Argon2id key derivation + ChaCha20-Poly1305).
- **Certificate pinning:** pass the server cert as `--ca-cert` so the client trusts only that server.
- **Sealed sender:** optional mode where the server cannot see who sent a message.
- **Dependency checks:** CI runs `cargo deny check` and `cargo audit` on every PR.
---
## License ## License