Commit Graph
5 Commits
Author SHA1 Message Date
Paul HittandClaude Opus 5 19add570cb Check the content envelope against envelopes the iPhone emitted
The content layer had no vectors. Everything from section 6.6 onward was
guarded only by same-code round trips: this engine encodes and parses
through its own codec and would pass unchanged if it and the iPhone
disagreed about every key. That is how SPEC 6.18 specified `ment` for as
long as it has existed while both clients have always sent `men`.

`content-v1.json` holds fifteen envelopes generated by RUNNING the
iPhone's encoders, and this suite parses each one and asserts field by
field. "It did not crash" is what the old tests already proved.

One of them pins something easy to get wrong twice: the iPhone writes
`fwd` as the integer 1, not as `true`, and `optBoolean` does not coerce a
number. A parser reading only the boolean answers false and the message
quietly loses the fact that it was passed on.

The suite also fails if the vector file grows a case nobody asserts on.

Separately, and the reason any of this is trustworthy: the test task did
not track the vector files at all. They arrive by environment variable,
Gradle does not track one as an input, so a vector could change under a
build directory that already had results and the task reported
UP-TO-DATE without running. That is not hypothetical here, it is how
twenty vector tests once passed in CI for weeks without executing, on
this same runner, whose build directory survives between runs. All six
vector files are now declared inputs.

Proven rather than asserted: with the inputs declared, flipping `men` to
`ment` in one vector turns the suite red without `--rerun-tasks`. Before
the fix the same change left it UP-TO-DATE and green.

Full suite: 1294 tests, no failures.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-09-11 07:20:17 -04:00
Paul HittandClaude Opus 4.8 a40cc2d2d4 Measure Android coverage, and round-trip the vault
JaCoCo was not configured on either JVM module, so the Android numbers
were unknown rather than good. :engine and :client are plain Kotlin/JVM
precisely so they can be measured without an emulator; now they are.
Baseline: engine 84.9% lines, client 47.3%.

Vault was the outlier in engine at 53%, and its uncovered half was almost
entirely save/load pairs — credentials, trust pins, the delivery key, the
key-log pins, the roster, avatars, per-line deletion.

That is not an arbitrary gap. It is the exact shape of a bug that has
already shipped in this app twice. `requireKeyLog` was computed, held in
memory and never written down, so a security control the UI offered
silently reverted on every relaunch. `Trust.changed` says the same thing
in its own doc comment: returned by `record()`, persisted by nothing, so
`state()` could never answer CHANGED, the "Accept new keys" button could
never render, and a contact who reinstalled became permanently
unmessageable while the header insisted nothing had changed.

Neither was hard to write. Both were invisible because a save and a load
that disagree still compile and only differ after a restart, which no
test performed. Every test here writes with one Vault and reads with a
second built over the same bytes, because that is the only arrangement in
which the two halves are forced to agree.

Includes the AAD binding the class doc promises: a trust record copied
into another contact's slot must not open, or someone with file access
could attribute a stranger's keys to someone you trust.

Vault 53.0% -> 84.9% lines, engine 84.9% -> 92.3%.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-08-30 09:13:26 -04:00
Paul HittandClaude Opus 5 5f983c1455 Android: the app, and the two things only a phone could tell us
There is now a Flamenet Messenger app that installs, launches, creates an
account on a self-hosted relay, registers a device, publishes prekeys, and
stores all of it in an Android Keystore-backed vault. Verified on an emulator
through the actual screens, not by unit test.

92 JVM tests, 37 cross-engine, 9 on-device, 3 against live relays.

Two findings, both of which the JVM suite was structurally incapable of
producing.

**Android has no ordinary Ed25519 provider.** `KeyPairGenerator.Ed25519` and
`KeyFactory.Ed25519` come from `AndroidKeyStore` and from nowhere else -- probed
on API 35 rather than assumed -- and Keystore only makes keys it keeps. Every
Ed25519 key in this engine is one we must hold: a device identity in our own
vault, an account key derived from a passphrase. So the JCA route could never
have worked. It compiled, passed 81 tests on a laptop, and threw "Not
initialized" on the first launch on a phone. Worse, it was LATENT: a wrong
password failed before any key was minted, so the error path worked perfectly
while the happy path was broken.

Ed25519 now uses BouncyCastle's `math.ec.rfc8032` core directly -- the engine's
one real dependency, present because the platform leaves a hole, and a strictly
better answer than the non-constant-time keygen it replaces. ProviderProbeTest
records the measurement so nobody guesses again.

**The prekey field is `prekeys`, not `opks`.** I guessed. The relay accepted the
registration, returned 200, and stored nothing -- so the device was published
and could not be started with, a failure with no error anywhere. Caught by a
live test against the throwaway fleet, which exists because the same path
through the emulator takes four minutes to say "timed out" and nothing about
where.

Two testing traps, recorded where they bite:

An indeterminate progress spinner animates for ever, so Compose's test clock
never goes idle and `waitUntil` never evaluates its condition -- it fails on the
full timeout, reading as "sign-up is broken" when sign-up works. Auto-advance is
now disabled around the wait only; disabling it for the whole test is the next
mistake, because the app opens on a spinner while it reads the vault.

Wiping the Keystore in `@Before` deletes the key the already-launched activity
is holding, and every later write fails against a key that no longer exists. The
test signs out through the UI instead, which is both safe and what a person does.

Failure messages now include what the screen was showing. A bare timeout sends
you to the network, the relay and the crypto in turn while the app has been
displaying the reason the whole time.

Also corrects a note that said this Mac had no Android SDK. It does.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-23 17:02:16 -04:00
Paul HittandClaude Opus 5 8a3770f1d1 Kotlin: the session layer, verified across the wire
An app does not use X3DH and a ratchet, it uses "send this string to that
person". This is that layer: device identities with prekeys and rotation,
envelopes as the relay actually carries them, and sessions that survive being
put away and taken out again.

11 unit tests, and the interop harness grows from 23 assertions to 37 -- the
new ones at the envelope level, which is where this protocol's one shipped bug
lived. A client and a relay disagreed about a field name and nothing caught it
until a live round trip; hand-assembled arguments to X3DH would not have.
Kotlin now builds a whole envelope, the web engine's own session layer parses
it, and both directions agree on the associated data.

Three decisions worth stating.

Retired signed prekeys are kept for longer than the relay keeps undelivered
mail. A sender fetches a bundle, encrypts against that prekey id, and the
envelope can then sit in a queue for the relay's full retention window.
Discarding the private half at rotation turns every one of those into an AEAD
failure -- which the receiving client cannot distinguish from an attack. A
prekey retired past retention is refused outright rather than guessed at, for
the same reason: guessing derives a garbage secret and reports it as tampering.

The handshake block rides every message until one is answered, not until one is
sent. Any message may be the first to arrive.

Sessions archive with their skipped message keys, and the harness proves it
against the peer rather than against our own bytes. Those keys are the messages
already in flight; an archive that drops them loses exactly the mail that was
in the air when the app was killed. The failure this whole path exists to
prevent is a client that loses session state, re-registers a device, and shows
every contact "security keys changed" -- the warning that is supposed to mean
an attack.

`org.json` is compileOnly: it is in the Android framework, so it costs nothing
on a phone and bundling a copy would shadow the platform's. Safe only because
the two encodings that must match byte-for-byte -- the ratchet header and the
canonical log leaf -- are built by hand; Android's implementation preserves key
order and the reference one does not.

Also adds PARITY.md: what the iOS app does, what Android does, what is left.
It is the definition of done, and a row moves only when something tests it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-23 15:12:14 -04:00
Paul HittandClaude Opus 5 06b97ca69b Start Android with the engine, held to the published vectors
Android does not exist, and the first thing it needs is not a screen. It
needs the protocol implemented a third time — which is only worth
anything if the third implementation is checked against the spec and the
published vectors rather than against a reading of our own Swift.

So `android/engine` is a plain Kotlin/JVM library with no Android in it:
no SDK, no emulator, no device, and therefore gateable in CI on Linux
like everything else. It reads
engine/test/vectors/protocol-v1.json from its one location rather than
carrying a copy, because a vector transcribed into the test that checks
it is a vector that agrees with itself.

Covered so far: safety numbers (§7) and key transparency verification
(§19) — RFC 6962 leaf and node hashing, the unbalanced split, and
bottom-up audit paths. Nine tests, all green against the same file the
JavaScript and Swift engines answer to.

The §19 tests are the ones worth having. A top-down reading of a
bottom-up audit path yields the correct root for every left-spine index,
so it passes any suite that only checks index 0 — the vectors pin a
right-descending index, and the tests assert both that the published
path verifies and that the same path reversed does not.

android/README.md lists what is missing — X25519, X3DH, the ratchet,
sealed sender, both post-quantum halves, the relay client, the app — as
a table rather than as an omission. Android stays honestly marked "not
started" on the site until that list is shorter.

Bytecode targets 17 without demanding a JDK 17 be installed: a
jvmToolchain(17) fails on any newer JDK, which is a poor trade for a
library with no JDK 17-specific behaviour.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-21 13:00:13 -04:00