Paul HittandClaude Opus 5.5 c62afdc152 Back up one-to-one threads under the user id, as the iPhone does
A one-to-one thread went into the shared backup under this app's own
name for it, "user:7", and came back under whatever key the file had.
The iPhone keys these threads "7" and skips any key that is not a
number, so every one-to-one conversation was lost when a backup moved
between the two phones, in either direction: the iPhone dropped
Android's threads, and Android filed the iPhone's under "7", where
nothing reads them.

The prefix now comes off on the way out and goes back on for a numeric
key on the way in. A file written before this, keyed "user:7", still
restores into the same thread. The test goes through the vault's own
export and import, where the payload-only checks passed all along; the
older tests that used a bare id as this app's thread name now use the
real one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-04 08:54:01 -04:00
2026-08-21 18:22:30 -04:00
2026-08-21 18:22:30 -04:00
2026-08-21 18:22:30 -04:00
2026-09-09 09:30:32 -04:00
2026-09-09 09:30:32 -04:00

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_HOME is 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.
S
Description
Flamenet Messenger for Android — the Kotlin engine, held to the published protocol vectors. No app yet. MIT.
Readme MIT
22 MiB
Languages
Kotlin 99.3%
Shell 0.6%
Python 0.1%