Paul HittandClaude Opus 5
cda64d8c2e
🔴 **The chat header said "keys unchanged since you met" while every send was refused with "identity keys changed".** Found by driving two real apps: the iOS side relaunched with -FNMSGResetState, which is a genuinely new device with new keys, and Android correctly refused to send to it. Correct — and then there was no way out. `Trust.state()` could return UNKNOWN, VERIFIED or PINNED and nothing else. CHANGED was computed inside `record()` while a send was in flight and thrown away, because `Vault.Trust` had nowhere to remember it. So: - the header kept reporting the OLD pinned keys as unchanged, - the "Accept new keys" button, which only renders for CHANGED, never appeared, - `acceptIdentityChange()` was unreachable from the UI, - and the contact stayed unmessageable for ever, with the app insisting nothing was wrong. That is precisely what a tester does on day one: reinstall, and discover their friend can no longer reach them. `Vault.Trust` now carries `changed`, `record()` persists the detection without adopting the offered keys and drops the verified tick (whatever was compared in person was compared against the old key), `state()` reports it, and accepting clears it. Keys that match again also clear it, so a transient wrong answer does not strand somebody behind a banner for ever. Verified live on the emulator: the banner appears with its full text, Accept new keys is reachable, and the header returns to "keys unchanged" afterwards. Four tests in TrustTest; three of them fail against the old `state()`. --- 🔴 **An expired session told the user their passphrase was wrong.** Hit immediately afterwards: a send failed with "That handle or passphrase isn't right", ten hours after a successful sign-in, because AccountsClient mapped EVERY 401 and 403 to BadCredentials. The natural reading is that the password stopped working or was changed by someone else, and the natural response is to change a password that was never wrong. Only `sessions` and `accounts` actually present a passphrase, so only those can report one as wrong. Everything else now raises SessionExpired, which the app states as what it is. Two tests cover both directions. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Flamenet Messenger — Android
Nothing here is an app yet. This is the engine, and it is deliberately first.
An Android client needs the protocol implemented a third time. That third
implementation is the one that finds the places where the specification says
less than the two existing engines quietly agreed on — but only if it is
written against the spec and the published vectors rather than against a
reading of our own Swift and JavaScript. So the engine comes first, it is a
plain Kotlin/JVM library with no Android in it at all, and it is held to
engine/test/vectors/protocol-v1.json — the same file the other two engines
are checked against, read from that one location rather than copied here.
./gradlew :engine:test
No Android SDK, no emulator, no device. It runs anywhere a JVM does, which is also what lets it run in CI on Linux.
What the engine covers today
| Area | Spec | State |
|---|---|---|
| Safety numbers | §7 | Done — fingerprints and conversation ordering match the published vectors |
| Key transparency verification | §19 | Done — RFC 6962 leaf/node hashing, unbalanced split, bottom-up audit paths |
| Byte helpers | — | Unsigned comparison, constant-time equality |
What it does not cover
Listed rather than left to be discovered, because a table of green ticks with the hard parts quietly missing is worse than no table:
| Area | Spec | State |
|---|---|---|
| X25519 / Ed25519 | §3 | Not started — needs a provider that works on both JVM and Android |
| X3DH key agreement | §4 | Not started |
| Double Ratchet | §6 | Not started |
| Sealed sender | §12 | Not started |
| ML-KEM-768 hybrid | §11 | Not started |
| ML-DSA-65 identities | §20 | Not started |
| Relay client | §8 | Not started |
| The app itself | — | Not started |
Until those exist, Android is honestly marked "not started" on the website, and a conversation gets the protocol's guarantees only when both ends are iOS.
Why the vectors matter more than the code
Two implementations that agree may both be wrong in the same way, especially when one was written while reading the other. The audit-path ordering in §19 is the worked example: a top-down reading of a bottom-up path produces the correct root for every left-spine index, so it passes any test that only checks index 0. The vector file pins a right-descending index for that reason, and the Kotlin tests assert both that the published path verifies and that the same path reversed does not.
If this engine ever disagrees with the file, the interesting question is which of the three is wrong — not this one by default.