Christian Nennemann
12846bd2a0
- Full table of mesh networking modules - FAPP protocol explanation with code example - Privacy model summary - Link to protocol spec
276 lines
12 KiB
Markdown
276 lines
12 KiB
Markdown
<p align="center">
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<img src="assets/logo.png" alt="quicprochat" width="160">
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</p>
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<h1 align="center">quicprochat</h1>
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<p align="center">
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<strong>End-to-end encrypted group messaging over QUIC, powered by MLS and post-quantum cryptography.</strong>
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</p>
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<p align="center">
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<a href="docs/src/design-rationale/messenger-comparison.md">Why quicprochat?</a> ·
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<a href="ROADMAP.md">Roadmap</a> ·
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<a href="docs/sdk/index.md">SDK Docs</a> ·
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<a href="docs/operations/monitoring.md">Operations</a> ·
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<a href="#quick-start">Quick Start</a>
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</p>
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---
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quicprochat 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.
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```
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┌─────────────────────────────────────────────────┐
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│ Application / MLS ciphertext │ ← group key ratchet (RFC 9420)
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├─────────────────────────────────────────────────┤
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│ Protobuf RPC / Cap'n Proto (legacy) │ ← typed, schema-versioned framing
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├─────────────────────────────────────────────────┤
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│ QUIC + TLS 1.3 (quinn/rustls) │ ← mutual auth + transport secrecy
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└─────────────────────────────────────────────────┘
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```
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## Highlights
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| | |
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| **Zero-knowledge server** | Routes opaque MLS ciphertexts by recipient key — never decrypts |
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| **Post-quantum ready** | Hybrid X25519 + ML-KEM-768 KEM on both MLS and Noise layers |
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| **Password auth** | OPAQUE — password never leaves the client, not even as a hash |
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| **Forward secrecy** | MLS epoch ratchet: compromise today can't decrypt yesterday |
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| **Multi-device** | Per-device keys, delivery fan-out, up to 5 devices per account |
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| **Federation** | Server-to-server relay over QUIC with mTLS |
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| **Offline-first** | Client-side outbox with idempotent retry and gap detection |
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| **Sealed sender** | Optional anonymous enqueue — server can't see who sent a message |
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| **7 SDKs** | Rust, Go, Python, TypeScript, Swift, Kotlin/Java, Ruby |
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## Quick Start
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```bash
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# Build (no system dependencies — protoc is vendored)
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cargo build --workspace
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# Run tests
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cargo test --workspace
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# Start the server (auto-generates self-signed TLS cert)
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cargo run --bin qpc-server -- --allow-insecure-auth
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# Interactive REPL (registers + logs in automatically)
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cargo run --bin qpc -- repl --username alice --password secret
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```
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**Two-terminal demo:**
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```bash
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# Terminal 1 # Terminal 2
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qpc repl -u alice -p secretA qpc repl -u bob -p secretB
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# Alice: # Bob sees:
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/dm bob [alice] Hello, Bob!
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Hello, Bob!
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```
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## Architecture
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```
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quicprochat/
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├── crates/
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│ ├── quicprochat-core # MLS, hybrid KEM, PQ Noise, OPAQUE, recovery, padding
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│ ├── quicprochat-proto # Protobuf (prost) + Cap'n Proto generated types
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│ ├── quicprochat-rpc # QUIC RPC framework (framing, dispatch, middleware)
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│ ├── quicprochat-sdk # Client SDK (QpqClient, conversation store, outbox)
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│ ├── quicprochat-server # QUIC server, 33 RPC methods, domain services, plugins
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│ ├── quicprochat-client # CLI + REPL + TUI (Ratatui)
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│ ├── quicprochat-kt # Key transparency (Merkle-log, revocation)
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│ ├── quicprochat-p2p # iroh P2P, mesh identity, store-and-forward
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│ ├── quicprochat-ffi # C FFI (libquicprochat_ffi.so)
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│ └── quicprochat-plugin-api # Dynamic plugin hooks (C ABI)
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├── proto/qpc/v1/ # 15 .proto schema files
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├── sdks/ # Go, Python, TypeScript, Swift, Kotlin, Java, Ruby
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├── docs/ # mdBook docs, SDK guides, operational runbooks
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└── packaging/ # OpenWrt, Docker, cross-compilation
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```
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### Security Properties
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| Property | Mechanism |
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| Transport confidentiality | TLS 1.3 over QUIC (rustls) |
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| Group key agreement | MLS `MLS_128_DHKEMX25519_AES128GCM_SHA256_Ed25519` |
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| Post-quantum confidentiality | X25519 + ML-KEM-768 hybrid KEM (MLS + Noise layers) |
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| Forward secrecy | MLS epoch ratchet + per-epoch key schedule |
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| Post-compromise security | MLS Update proposals rotate leaf material |
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| Identity | Ed25519 long-term keys (MLS credential + leaf signature) |
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| Password authentication | OPAQUE-ke (augmented PAKE, no password on wire) |
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| Local storage | SQLCipher + Argon2id + ChaCha20-Poly1305 |
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| Key transparency | Append-only Merkle log with inclusion proofs + revocation |
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| Traffic analysis resistance | Uniform padding + configurable decoy traffic |
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## Features
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### Messaging
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- **1:1 DMs** and **N-party groups** with full MLS lifecycle (add, remove, key rotation)
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- **Rich messaging** — reactions, read receipts, typing indicators, edit, delete
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- **File transfer** — chunked upload/download, SHA-256 content addressing, 50 MB limit
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- **Disappearing messages** — per-conversation TTL with server-side GC
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- **Offline queue** — messages queued locally when disconnected, flushed on reconnect
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- **Delivery proofs** — server-signed Ed25519 receipts for cryptographic send confirmation
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- **Transcript export** — encrypted, tamper-evident archives with Merkle chain verification
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### Infrastructure
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- **Multi-device** — per-device keys and delivery fan-out (up to 5 devices)
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- **Account recovery** — 8 recovery codes, encrypted bundles, zero-knowledge server
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- **Federation** — server-to-server relay with mTLS and cross-server user resolution
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- **Abuse prevention** — user blocking, message reporting, ban enforcement, admin tools
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- **Graceful shutdown** — SIGTERM drain with configurable timeout, health endpoint awareness
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- **Rate limiting** — sliding window algorithm, trait-based for Redis swap
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- **Observability** — request correlation IDs, per-endpoint latency histograms, structured audit log
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- **Dynamic plugins** — load `.so`/`.dylib` at runtime via `--plugin-dir` (6 hook points)
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- **Mesh networking** — iroh P2P, mDNS discovery, store-and-forward, broadcast channels
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### Mesh & P2P Features
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The `quicprochat-p2p` crate provides a full **serverless mesh networking stack**:
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| Feature | Module | Description |
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|---------|--------|-------------|
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| **P2P Transport** | `P2pNode` | Direct QUIC connections via iroh with NAT traversal |
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| **Mesh Identity** | `MeshIdentity` | Ed25519 keypairs with 16-byte truncated addresses |
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| **Mesh Envelope** | `MeshEnvelope` | Encrypted, signed, TTL-aware message containers |
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| **Store-and-Forward** | `MeshStore` | Queue messages for offline recipients |
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| **Multi-Hop Routing** | `MeshRouter` | Distributed routing table, forward through intermediaries |
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| **Announce Protocol** | `MeshAnnounce` | Signed peer discovery with capability flags |
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| **Broadcast Channels** | `BroadcastManager` | Pub/sub with symmetric key encryption |
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| **Transport Abstraction** | `TransportManager` | Iroh, TCP, LoRa — route by address type |
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| **LoRa Transport** | `transport_lora` | Duty-cycle aware, fragmentation, SF12 support |
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| **MLS-Lite** | `mls_lite` | Lightweight symmetric mode for constrained links |
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| **FAPP** | `fapp` + `fapp_router` | Free Appointment Propagation Protocol (see below) |
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#### FAPP — Decentralized Appointment Discovery
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**Problem:** In Germany, finding a psychotherapist takes 3–6 months due to artificial slot visibility limits.
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**Solution:** FAPP lets licensed therapists announce free slots into the mesh. Patients discover and reserve slots anonymously — no central registry.
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```rust
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// Therapist publishes slots
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let announce = SlotAnnounce::new(
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&therapist_identity,
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vec![Fachrichtung::Verhaltenstherapie],
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vec![Modalitaet::Praxis, Modalitaet::Video],
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vec![Kostentraeger::GKV],
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"80331", // PLZ only, never exact address
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slots,
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approbation_hash,
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sequence,
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);
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fapp_router.broadcast_announce(announce)?;
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// Patient queries anonymously
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let query = SlotQuery {
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fachrichtung: Some(Fachrichtung::Verhaltenstherapie),
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plz_prefix: Some("803".into()),
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kostentraeger: Some(Kostentraeger::GKV),
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..Default::default()
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};
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fapp_router.send_query(query)?;
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```
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**Privacy model:**
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- Therapist identity is **public** (bound to Approbation hash)
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- Patient queries are **anonymous** (no identifying information)
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- Reservations use **E2E encryption** to therapist's key
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See [`docs/specs/fapp-protocol.md`](docs/specs/fapp-protocol.md) for the full protocol spec.
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### Client SDKs
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| Language | Location | Transport | Notes |
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| **Rust** | `crates/quicprochat-sdk` | QUIC (quinn) | Reference implementation |
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| **Go** | `sdks/go/` | QUIC (quic-go) | Cap'n Proto RPC, full API |
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| **Python** | `sdks/python/` | QUIC (aioquic) + FFI | Async client, PyPI-ready |
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| **TypeScript** | `sdks/typescript/` | WebSocket + WASM crypto | 175 KB WASM bundle, browser demo |
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| **Swift** | `sdks/swift/` | C FFI wrapper | iOS 15+ / macOS 13+ |
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| **Kotlin/Java** | `sdks/kotlin/`, `sdks/java/` | JNI + C FFI | Android + JVM |
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| **Ruby** | `sdks/ruby/` | C FFI gem | Block-form auto-disconnect |
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### REPL Commands
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40+ slash commands including:
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```
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/dm <user> Start a 1:1 DM
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/create-group <name> Create a group
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/invite <user> Add member to group
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/remove <user> Remove member
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/send-file <path> Upload and send a file
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/verify <user> Compare safety numbers
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/rotate-keys Rotate MLS key material
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/disappear <duration> Set message TTL
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/export <path> Export encrypted transcript
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/devices list|add|rm Manage devices
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/block <user> Block a user
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/recovery setup Generate recovery codes
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/help Full command reference
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```
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## Deployment
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### Docker
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```bash
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docker build -t quicprochat -f docker/Dockerfile .
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docker run -p 7000:7000 -v qpc-data:/data quicprochat
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```
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### Production (Docker Compose)
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```bash
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# Includes server + Prometheus + Grafana with pre-configured dashboards
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docker compose -f docker-compose.prod.yml up -d
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```
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### OpenWrt
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Cross-compiled static binaries for mesh/embedded deployments:
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```bash
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./scripts/cross-compile.sh # builds for x86_64, armv7, aarch64 (musl)
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```
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See [docs/openwrt.md](docs/openwrt.md) for `opkg` packaging and `procd` init scripts.
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### Configuration
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```bash
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# Environment variables (see .env.example for full list)
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QPC_LISTEN=0.0.0.0:7000
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QPC_AUTH_TOKEN=your-strong-token
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QPC_DB_KEY=your-db-encryption-key
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QPC_STORE_BACKEND=sql
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QPC_METRICS_LISTEN=0.0.0.0:9090
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QPC_DRAIN_TIMEOUT=30
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QPC_RPC_TIMEOUT=30
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```
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## Documentation
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```bash
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mdbook serve docs # http://localhost:3000
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```
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- [SDK Integration Guide](docs/sdk/index.md) — wire format, per-language guides, "build your own SDK"
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- [Operational Runbook](docs/operations/backup-restore.md) — backup/restore, key rotation, incident response
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- [Scaling Guide](docs/operations/scaling-guide.md) — resource sizing, horizontal scaling, capacity planning
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- [Monitoring](docs/operations/monitoring.md) — Prometheus metrics, Grafana dashboards, alert rules
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## Security Status
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> **This software has not undergone an independent security audit.** While it implements cryptographic best practices (MLS RFC 9420, OPAQUE, zeroization, constant-time comparisons), no third-party firm has reviewed the implementation. Do not rely on it for high-risk communications until an audit is completed. See [SECURITY.md](SECURITY.md) for our vulnerability disclosure policy.
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## License
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MIT
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