Fixes the prekey-bundle PR review + CI failure:
- CI root cause: the receive queue (mesh.message) is concurrent, so a
gossiped prekey bundle can be processed before the announce that binds
its owner's signing key. The old handler dropped such bundles outright,
so under CI parallel load the bundle was permanently lost and the
cache/gossip tests flaked (verifiedBundleEntersGossipStore,
prekeySealedMailTravelsViaCourierAndOpens). Bundles that arrive before
their binding are now retained per-owner (bounded) and re-attempted when
the verified announce lands, atomically to avoid a check-then-act race.
- Authenticate the OUTER prekey-bundle packet (Codex P2 / review MEDIUM):
require senderID == PeerID(bundle.noiseStaticPublicKey) and verify the
packet's Ed25519 signature (covers senderID + timestamp) against the
owner's bound signing key, in addition to the inner bundle signature.
Stops replay under a fresh timestamp / fake senderID.
- Key the gossip prekey-bundle store/dedup by the bundle's authenticated
identity (noiseStaticPublicKey), not the unauthenticated packet
senderID, so one valid bundle sprayed under many fabricated sender IDs
can't multiply entries and exhaust the 200-owner cap.
- Bump published-bundle generatedAt strictly on consume (Codex P1):
consuming a prekey shrinks the published bundle, so it now republishes
with a strictly newer generatedAt and re-gossips, so peers replace the
cached copy and stop assigning the consumed ID before its 48h grace.
- Guard the panic/clear detached Application Support tree-deletes behind
TestEnvironment.isRunningTests: the SPM test process shares that tree,
so the wipe could land mid-test and flake file-dependent tests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Courier envelopes were sealed with one-way Noise X to the recipient's
long-lived static key, so a later compromise of that key exposed every
envelope captured in transit. This adds one-time prekey bundles:
- PrekeyBundle (MessageType 0x24): 8 one-time Curve25519 public prekeys
bound to the owner's Noise static key by an Ed25519 signature over
"bitchat-prekey-bundle-v1" canonical bytes; gossiped mesh-wide on its
own 60s sync round (SyncTypeFlags bit 9, 200-peer cap, 24h freshness)
and verified against the announce-bound signing key before caching.
- Sealed envelope v2: Noise X where the responder static is the one-time
prekey, prologue "bitchat-prekey-v1" || prekeyID. Sender identity rides
encrypted inside and is authenticated exactly like v1 (blocked-sender
check included). CourierEnvelope gains an optional prekeyID TLV that
v1 decoders skip as unknown.
- Local prekeys live in the Keychain; consumed privates survive a 48h
grace window for spray-and-wait redeliveries, then are deleted (the
forward-secrecy clock starts at deletion). The batch tops back up and
re-gossips when unconsumed count drops below 3, and everything is
wiped in panic mode.
- Routing: courier sealing picks a cached verified bundle when one
exists (one prekey per message, reused across deposit retries), with
the advertised .prekeys capability as a veto for on-mesh peers, and
falls back to static sealing otherwise.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
