Paul HittandClaude Opus 4.8
f9f063a211
The relay has had per-conversation lifetimes since the port and **no client could set one** — its own comment says so. For E2E conversations the server timer would not have helped anyway: it expires rows in the legacy plaintext table, not the envelopes these apps actually exchange. So this is client-side, which is also the only place it can be honest. **Symmetric.** Either party sets the timer; the other is told inside the ratchet and adopts it. A timer only the setter honoured would be worse than none — they would believe their words were gone from a phone still holding them. **Inside the ratchet**, so the relay never learns that a conversation is timed, let alone for how long. It rides as ordinary control traffic carrying the `ctl` flag from §6.10, which is what makes it safe to add at all: without that, this envelope would surface in every older install as an "[unsupported attachment]" bubble. **Expiry runs on read**, in `Vault.history`. A sweep on a timer leaves expired messages on disk between runs, and a disappearing message still sitting in the vault is a claim rather than a feature. Reading is the one path every caller shares, so nothing can see — or keep — an expired message. ⚠️ **Ages come from this device's own timestamp**, not one the peer supplies. "From send time" in practice means when this device sent or received it, which differs by seconds and cannot be manipulated: a peer who chose the clock could backdate a message so it vanished from your phone immediately, or forward-date one so it never expired. ⚠️ **A message with no timestamp is kept.** Those predate the field, and an unknown age is not evidence of an old one — deleting somebody's history on a guess cannot be undone. The panel sits on the thread rather than in a menu, because "fewer taps to turn it on" and "clearer per-conversation state" are the same problem: a timer nobody can see is one nobody trusts. Presets only — arbitrary durations are the ones nobody can reason about later. engine 155, client 94, app 32. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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_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.