MLS-Lite provides group encryption without full MLS overhead:
- Pre-shared group secret (QR code, NFC, or MLS epoch export)
- ChaCha20-Poly1305 symmetric encryption (same as MLS app messages)
- Per-message nonce from epoch + sequence
- Replay protection via sliding window
- Optional Ed25519 signatures
Wire overhead: ~41 bytes without signature, ~105 with signature
(vs ~174 bytes for MeshEnvelope V1)
Tradeoffs vs full MLS:
- No automatic post-compromise security (manual key rotation)
- No automatic forward secrecy (only per-epoch)
- Keys are pre-shared, not negotiated
Designed for SF12 LoRa where MLS KeyPackages are impractical.
S5: Compact envelope format for constrained links:
- 16-byte truncated addresses (MeshAddress) instead of 32-byte keys
- 16-byte truncated content ID
- u16 TTL and u32 timestamp (smaller than V1)
- Priority field (Low/Normal/High/Emergency)
- ~30-50 bytes savings per envelope vs V1
Full public keys are exchanged during announce phase and cached in
routing table. Envelope only needs addresses for routing.
Implement transport abstraction (TCP/iroh), announce and routing table,
multi-hop mesh router, truncated-address link layer, and LoRa mock
medium with fragmentation plus EU868-style duty-cycle accounting.
Add mesh_lora_relay_demo and scripts/mesh-demo.sh. Relax CBOR vs JSON
size assertion to match fixed-size cryptographic overhead. Extend
.gitignore for nested targets and node_modules.
Made-with: Cursor
Rename all crate directories, package names, binary names, proto
package/module paths, ALPN strings, env var prefixes, config filenames,
mDNS service names, and plugin ABI symbols from quicproquo/qpq to
quicprochat/qpc.
