Marked ⚪ and implemented the whole time. Every read goes to disk:
`Session.history` calls `Vault.history`, which decrypts the record. There
is no in-memory copy to be fooled by.
Checked against iOS's `E2EHistoryStore` rather than assumed. Same cipher,
same posture, two honest differences recorded rather than papered over:
- 🟢 Android binds the RECORD NAME into the AAD, so a sealed blob cannot
be moved between slots. iOS keeps one snapshot file and does not need
that — but would, the day it splits.
- iOS's `.completeFileProtection` is a per-file assertion. Android's
equivalent is Credential-Encrypted storage, a property of the volume
rather than of this app's request.
Neither favours one platform overall, and both clients agree on the
behaviour that matters: a plain sign-out KEEPS history, and erasing the
device destroys it — on Android by wiping every record and deleting the
Keystore key, so what is left is unopenable as well as gone.
⚠️ Also recorded: `Vault.history` prunes expired messages on the way out,
so disappearing messages are enforced on READ rather than by a timer
nothing runs — and it rewrites the record only when something actually
expired, so a read is not a write.
Services (AIM/ICQ) retired rather than left as a gap: not a goal for this
app (owner, 2026-09-04).
That leaves only the two post-quantum rows, and the note above them
already says why they are not a gap in effect: iOS's PQ files are inert
because CryptoKit exposes ML-KEM on iOS 26 and the app targets 16, so
neither client does post-quantum anything today. Closing it properly is
one decision for both clients, not an Android task.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
