meshbay.git/packages/meshbay-common/src/meshbay_common/senderkeys.py, branch main

refactor(common): delete the sender-key implementation nothing uses

2026-09-10T15:30:22Z

`senderkeys.py` and its 13 tests implemented Signal-style sender keys, and production has never called them: chat is a key per group, per epoch, per device, derived by name. The reasoning that ruled the ratchet out stays where it belongs — in `chatbox.py`, at the top of the module that replaced it — because the argument is the useful part, and it now stands on its own instead of pointing at a file to compare against. Kept code that nothing calls is worse than absent code: it reads as an alternative somebody may reach for, and it has to be maintained past every refactor to stay compiling, which is maintenance spent on a decision already made. The three comments naming `GroupSenderKeyStore` are rewritten to say the thing they were illustrating. Co-Authored-By: Claude Opus 5 Claude-Session: https://claude.ai/code/session_01AsoWC3GmhNdwVFomW3QjH3

feat(chat): encrypt group chat under per-device epoch keys (MNP 2.0)

2026-09-07T15:50:28Z

Chat messages are sealed with AES-256-GCM under a key derived per group, per epoch, per *device*, and signed over the ciphertext with the device key the node pinned. The node relays and archives; it cannot read a message. There is no switch. MNP goes to 2.0 and MNP_MIN_SUPPORTED moves with it, so a 1.x peer is refused at the handshake with `version_too_old` rather than admitted and then unable to speak. An opt-in flag was designed and rejected: every node is a test node, so it would have bought nothing and left a plaintext branch reachable — C6's lesson one feature later. A test reads the source and refuses any code that consults a `chat_encrypted` setting. Not Sender Keys, and `senderkeys.py` is now documented as unused. With distribution under the group key and a node that serves history to devices which were not present, the node must retain each chain's earliest key, and a chain key at iteration i yields every message key from i on by pure HKDF — forward secrecy is zero either way. What the ratchet was left buying was stateful client code with silent failure modes, three of them reproduced: any member could sign as any other, a second device dropped the first's chain, and the skipped-key cache grew without bound. The reasoning is in docs/chat-sender-keys.md, which is the specification and the decision record. Epochs, not rotation: the epoch key is wrapped under the group key at delivery and never stored under it, so `gek_rotate` is a re-wrap. A group-key-derived archive key would have made every message ever sent unreadable on the first `member unpin`, which is the documented step after removing a member. A new epoch opens on member revoke/unpin, device revoke and `gek_rotate`; old epochs are kept and still delivered, so history stays readable to everyone who could already read it, and nothing anywhere deletes one. Three prerequisites this needed, each a live defect on its own: * The peer registry was keyed by user_id, so one account's second device evicted the first and the broadcast skipped recipients by account — a person's phone never saw what they typed on their laptop. * The handshake authenticated an account, never a device. `device_hello` (additive, signed, refused unless the key is a live device of this account in the node's own roster) is what lets the node refuse a member claiming somebody else's key. * `_admin_exec_file_delete` authorized against the exact uploading key, so device linking had already broken deleting your own file from your other device. It now authorizes against any non-revoked device of `uploader_id`. Found by driving the real panel over the real transport, not by reading source: `chat_keys_resp` was routed by arrival order and handed to an unanswered `media_meta_req` — the original frozen-tab defect in a message type that did not exist when that probe was written. And `_asText` had been deleted with an unrelated helper beside it; its only caller sits inside a promise the panel catches, so every conversation rendered empty with nothing in the console. Existing node data is migrated by QE/migration/migrate_chat_encryption.py (not versioned, per the QE rule), run with the node stopped. Co-Authored-By: Claude Opus 5 Claude-Session: https://claude.ai/code/session_01TZZxYjz8YeWRz13xDi8LJr

feat: Phase 7 — Node v2 (multi-group, Sender Keys, 0-RTT, chat, denylist)

2026-08-10T01:07:56Z

Implements all 8 milestones (7.0-7.7): - 7.0: JWT carries `groups` claim; node verifies group membership at MNP handshake (QUIC + TCP+TLS). Resolves security review C2. - 7.1: QUIC 0-RTT session resumption via stored session tickets (17-21ms reconnect vs 47ms cold). - 7.2: Hub→node WebSocket signaling for NAT punch coordination (`client_incoming`/`punch_ready`) + jti denylist push. Denylist class blocks revoked users/jtis at handshake. - 7.3: Multi-group daemon — one QUIC port serves N groups with per-group GEK, shared_root, and index routing. - 7.4: HLS streaming via QUIC (STREAM_SEGMENT message type, ffmpeg segment extraction). - 7.5: Sender Keys protocol for group chat (Signal Groups approach). Each member has own sending chain key, HKDF chain ratchet, AES-256-GCM encryption, Ed25519 signing. Resolves security review C1. - 7.6: Chat store (SQLite via aiosqlite), CHAT_MESSAGE MNP wire type with peer broadcast, web UI with WebSocket push. - 7.7: Argon2id calibration CLI. First security review included (first-review.md). 109 tests, demo-v3 validated against meshbay.org production hub. Co-Authored-By: Claude Opus 4.6