Paul HittandClaude Opus 5.5
c0d88e85ec
DESIGN items 25, 26, 33 and 44, with the iPhone's bytes:
{"fnc":1,"kind":"unpost","ctl":1,"st":1,"sid":"<story id>"}
{"fnc":1,"kind":"unpost","ctl":1,"st":1,"set":"<set.id>"}
{"fnc":1,"kind":"edit","st":1,"caption":"<new words>",
"re":{"mid":"<story id>","author":0,"preview":""}}
The story id is the one §6.20 replies already use here: a picture's
attachment id, a text story's mid.
Taking a story down removes this phone's copy at once, from the strip
and the archive, with its reactions and any decrypted bytes, then tells
everyone it went to: the people recorded when it was posted, now kept
on each story, or for one posted before that or restored from a backup,
a group story's roster or today's story audience, and the change says
which. A set comes down whole by its id. This account's other phones
are told too. Both kinds are silent control traffic and never queued.
A receiver applies either only to a story it holds from the envelope's
sender. An unknown id, a take-down naming both a story and a set or
neither, an edit that would empty a story, and an older edit after a
newer one (by the relay's time) all change nothing. None is drawn and
none notifies. A story's edited time travels in backups; who it was
sent to stays on the phone.
The relay has no route to delete a blob, so a taken-down picture's blob
waits for the retention purge.
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.