Files
amethyst/quartz/tools
Claude 1d66e4e2f6 feat(marmot): implement account identity proof v2, the current profile's leaf binding
Stage 2 of the Marmot resync. A member leaf carries two unrelated keys — the
MLS BasicCredential identity, which is the member's Nostr account key, and the
MLS leaf signature key MLS generates per device — and MLS never checks that the
account agreed to the leaf key next to it. Without a proof, anyone able to
author a leaf can claim any account's identity.

This is also what makes us classifiable at all. MDK decides Legacy vs Current
purely on whether a group requires extension 0xf2f1 or component 0x8009; we
required neither, so profile classification errored out before any component
check ran.

Adds the common authorization-proof envelope (foundation/authorization-proofs.md):
104 fixed-width bytes of signer pubkey, big-endian uint64 timestamp and BIP-340
signature, with event-id reconstruction. The created_at bounds are load-bearing
twice over — the lower bound rejects zero, and the upper bound (2^53-1) catches
a uint64 whose top bit is set, which reads back negative as a Kotlin Long.

Deliberately absent: any comparison of created_at against a local clock. A proof
authorizes a long-lived key binding, not a one-time operation, and a wall-clock
rule would let skew make two members reach different verdicts on the same Commit.

The component itself signs a kind-450 template through NostrSigner rather than
raw BIP-340, which is the whole point of the indirection: a NIP-46 bunker or
NIP-55 app can produce a proof without exposing arbitrary signing. create()
therefore re-verifies everything the signer returned — pubkey, timestamp, kind,
tags, content, recomputed id, signature — since an external signer is free to
substitute a stale or altered event.

Also adds the app-component id registry, and the RFC 9420 signature-scheme
mapping to MlsCiphersuite (declared outside the companion: an enum's entries
initialize before its companion object, so entry constructor arguments cannot
read companion properties).

Tested two ways. Sixteen tests pin the spec's published fixture — canonical
event serialization, event id, signature, the 104-byte layout — and check that
every signed input actually binds, including a ciphersuite change that leaves
the signature scheme untouched. Six more validate the proofs in
marmot-current-profile.json: those come from a separate implementation, for
randomly generated keys, which is the interop property a fixed vector cannot
establish. Full quartz marmot suite: 395 tests, 0 failures.

Nothing reads or writes these on a real leaf yet — the carrier is the
app_data_dictionary, which is Stage 1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016kCuA6tc4JQzHPCDd39GHq
2026-09-08 15:04:59 +00:00
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