Paul HittandClaude Opus 5
9ced7dc3f0
"Self-hosted with shared identity" could not work. Both clients decided where accounts lived from a hardcoded list of relay hostnames, and a stranger's relay is never on that list -- so somebody self-hosting could have the shared FlameNet account service configured on their relay and the app would still authenticate against the relay itself. Mode 2 existed on the server and nowhere else. The relay already published the answer at `/.well-known/flamenet/relay`: `accounts: shared|local` and the service URL. Nothing read it. Now the client asks, and then checks the answer against a pinned list of account SERVICES rather than of relays. That keeps the property the hostname list was protecting -- an operator cannot point their users' passphrase-derived secrets at a host they control, because a service the client does not already trust is treated as local -- while letting any relay adopt the shared service. Unknown or unreachable descriptor also means local, which is the safe direction: the passphrase goes only to the server the user typed in. relay2 is now configured as that third shape, so all three exist to test: managed (relay.flamenet.io), self-hosted shared (relay2), self-hosted local (relay1, relay3). `LiveShapesTest` covers sign-up three rounds per shape, a conversation per shape, that each relay reports what it actually is, and that a relay naming an untrusted account service is refused. Fresh handles every round, so rounds are repeatable by construction rather than by cleanup. ⚠️ Two things worth keeping: Skips are announced. `return` from an unmet precondition makes a test that did nothing report PASSED -- I had four of those reporting green before switching to `assumeTrue`, which is the same silent-skip trap I had already criticised in the Swift interop harness. A suite of silent skips is indistinguishable from a suite that works. The handle travels beside the shared-session token, never inside it. The account service will not put a handle in a token, so a relay cannot correlate its users with another product's; the relay keys on the product-scoped pseudonym and uses the handle only the first time it sees one. Tested by signing in twice and asserting the same relay account comes back. Also deploys the discovery-document fix to relay.flamenet.io, with a database backup and a rollback image. The transparency-log root is byte-identical after the deploy. 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.