Paul HittandClaude Opus 4.8 f95cb1e6aa Keep a half-written message across a relaunch
Sealed in the vault, not in SharedPreferences — and that is the whole
point. A draft is plaintext the person has not decided to send, very
often the most sensitive text in the app because it is the thing they
are still weighing. SharedPreferences writes readable XML that survives
into backups; the vault seals it under the conversation's own key with
the record name bound into the AAD, and forgetEverything takes it on
sign-out. There is a test that asserts the bytes on disk do not contain
the text, because the wrong implementation would pass every other test
here.

Keyed by the same threadFor* ids the transcript uses, so a group called
"7", the contact who is user 7, and the address "7" are three
different drafts.

Every write to the composer state goes through one setDraft: send clears
it by assigning directly in three places, and any one of those that
forgot to clear the stored copy would bring the message back next time
as a draft of something already sent.

Closes #47 on iOS side; Android half of the same feature

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-09-02 15:50:01 -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
2026-08-21 18:22:30 -04:00
2026-08-21 18:22:30 -04:00

Flamenet Messenger — Android

The Android app, and the two libraries under it.

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 as of 2026-08-28: messaging, groups, attachments, voice notes, stories, calls, sealed sender, key transparency and the encrypted vault are built and tested; a cross-platform round trip against iOS was verified on 2026-08-26.

⚠️ This file said "Nothing here is an app yet" until 2026-08-28, above a tree containing the finished app — the README described the repository as it was when the engine landed and nothing updated it as the app grew around it. 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
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