Paul HittandClaude Opus 5
f2d74cff0c
Groups were 100% broken on iOS -- not partly, entirely -- because the client
required a `name` on each member that the relay has never sent. Every group
decode failed, so the feature looked implemented and did nothing.
So this one was built by reading the relay's wire types first and asserting
them against live bytes second. `Member` is `{user_id}` and only that: the relay
has no user table and deliberately will not grow one, because a relay caching
display names is a relay that leaks them. Names are resolved client-side from
the contact list, and a member you have never added shows as an id, which is
honest.
Create, list, open, add and remove members, leave, and send -- all verified
against relay1, including that a group message carries its routing so it files
under the group rather than under whoever sent it.
Two things worth stating plainly:
The relay does no fan-out. A group is a membership list it keeps so clients
agree who is in it; the encryption is still pairwise, one ratchet per recipient
device. An n-person group is n sends. That is the honest cost of the relay not
being able to read anything, and the client is what knows it.
Thread history is now keyed by an opaque thread id -- `user:<id>` or
`group:<gid>` -- rather than by user. Filing a group message under its sender
scatters one conversation across as many threads as it has participants.
Leaving a group also clears its local thread. Keeping it would leave a
conversation nobody can add to and no way to remove it.
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.