MIP-03 ("Application Messages" → Security Requirements) is explicit:
> "Inner events MUST remain unsigned (no `sig` field)
> This ensures leaked events cannot be published to public relays."
Authentication comes from (a) MLS framing — the sender's LeafNode
credential signs the outer MLS Application message — and (b) the
mandatory check in MarmotInboundProcessor.processPrivateMessage that
the inner event's `pubkey` equals the MLS sender's credential identity.
The Nostr Schnorr signature is redundant, and leaving it populated
means a leaked plaintext can be replayed as a valid public kind:9.
whitenoise-rs is spec-compliant (builds via `UnsignedEvent::new()` +
`ensure_id()`, never calls sign). Amethyst was the non-conforming side
on both directions:
1. Send path (`MarmotManager.buildTextMessage`,
`AccountViewModel.sendMarmotGroupMediaMessage`) called
`signer.sign(template)`, producing a signed rumor that shipped a
valid Schnorr signature through the encrypted channel. Switch both
to `RumorAssembler.assembleRumor` — same id derivation (SHA-256
over canonicalized [0, pubkey, createdAt, kind, tags, content]),
but `sig = ""`.
2. Restore path (`Account.kt` on startup reload of persisted inner
events) called `cache.justConsume(innerEvent, null, false)`, which
routed through `consumeRegularEvent` → `justVerify` → `event.verify()`
→ FAIL on empty sig → Note registered with `event = null`, message
never rendered. Pass `wasVerified = true`, matching what the live
receive path already does after the previous commit (573c5c2b).
Existing on-disk persisted messages from older signed-rumor builds
still load — `wasVerified=true` skips sig verify entirely, so both
legacy signed and spec-correct unsigned rumors deserialize cleanly.
Claude
5a18dc41c8