Paul HittandClaude Opus 5.5
d72a852899
The iPhone app has said both since 2026-09-23 (flamenetmessenger e030d63c). Android had the same facts and kept them to itself. F2, SPEC section 14.5: "a user who has enabled sealed sending SHOULD be told when a message could not be sent sealed." A send falls back to an identified one when the recipient's delivery key has gone stale. It is still encrypted per device; what changes is that the relay is told who sent it. The sealing record in Privacy counted that, which answers "how often" and never "did this one". The conversation now says so, in the same words as iOS, keyed on the peer the send was to. onSendSealed carries the peer id for that. In memory only, as on iOS, and a later sealed send does not take it back, because the message that went identified still did. F5. The account key comes from the passphrase and a salt the account service hands back at every sign-in and never stores on the phone, so that service can serve a different salt, the phone derives a different fnid, and the sign-in still succeeds. The new fnid replaced the old one in the saved credential with nothing comparing them. It is compared before the save now, for the same account on the same relay only (a different account on a shared phone is a different person), and the old address is shown above Your address in Settings. What this does not fix is custody: the salt still lives on one service. Eleven tests. The notices are rendered with Compose and read back, the two pure pieces are tested including their controls (same address is no change; a sealed send records nothing), and the call sites are pinned from source because losing any of them changes nothing a user would see: the message still sends and the sign-in still works. Falsified by unhooking the chat screen and making the record ignore whether the send was sealed; three tests fail. 358 app unit tests, no failures. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Flamenet Messenger. Android
The Android app, and the two libraries under it. The product's site is at https://flamenetmessenger.com.
engine/ the protocol: X3DH, Double Ratchet, sealed sender, safety numbers,
key transparency. Plain Kotlin/JVM, no Android in it at all.
client/ the relay transport: HTTP, auth, the §8 routes.
app/ the Compose app.
interop/ the cross-engine driver; not shipped.
engine and client are deliberately plain JVM libraries. The protocol has
nothing to do with Android, and keeping it off the platform means their tests
run anywhere a JVM does, no SDK, no emulator, no device, which is also what
lets them gate in CI on Linux:
./gradlew :engine:test :client:test
The app's own unit tests need the Android SDK but still no emulator (Robolectric):
./gradlew :app:testDebugUnitTest
Where it stands
PARITY.md is the definition of done for this app, read that, not this. Every row there names the iOS file it came from so it can be re-checked rather than trusted. Headlines: messaging, groups, attachments, voice notes, stories, calls, sealed sender, key transparency and the encrypted vault are built and tested, and a cross-platform round trip against iOS is verified.
If a claim here ever disagrees with PARITY.md or with the tree, believe those, and fix this.
Why the engine came first, and is held to the vectors
An Android client needs the protocol implemented a third time, and the 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 is held to
test/vectors/protocol-v1.json in
flamenet-e2e, the same file the
other two engines are checked against, read from that repository rather than
copied here, because a copied vector file drifts and a drifting vector file
stops being a check. PublishedVectorsTest looks for it beside this checkout
and fails loudly if it cannot find it; FLAMENET_VECTORS overrides the search.
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.
Contributing and security
- CONTRIBUTING.md, building (JDK 21,
JAVA_HOMEis not optional on a Mac), the test gate, and the platform traps that cost an hour each. - PARITY.md, what iOS does, what this does, and what is left. It is the definition of done for this app.
- SECURITY.md, threat model and where to send a vulnerability report. Not an issue tracker matter: security@flamenetmessenger.com.