marmot-ts (the TypeScript Marmot client — browsers, Node, Bun, Deno)
wraps a completely different MLS implementation: ts-mls. That backend
shares no code with OpenMLS, which is what MDK/whitenoise use, so
Amethyst passing on both is a strong signal that the on-wire MLS layer
is spec-correct rather than coincidentally self-consistent.
Add a Node-based generator under quartz/tools/tsmls-vector-gen/ that
uses ts-mls 2.0.0-rc.10 directly to emit:
- Alice's KeyPackage + Bob's joiner KeyPackage
- Alice's Welcome after add_member + commit
- Bob's init/encryption/signature private keys (PKCS#8 Ed25519 unwrapped
to the raw 32-byte seed for parity with the MDK vector shape)
- Post-join MLS-Exporter("marmot","group-event",32) KAT
- Three application PrivateMessages from Alice → Bob with the
expected plaintexts
TsMlsWelcomeInteropTest mirrors MdkWelcomeInteropTest but consumes the
new vector. It proves:
- KeyPackage self-signature verifies under our Ed25519 + SignContent.
- Amethyst.processWelcome unwraps the group secrets, derives the
welcome_key/nonce, AEAD-decrypts GroupInfo, verifies GroupInfoTBS
with signer_pub, decodes the ratchet tree, and binds the joiner's
leaf — end-to-end.
- Post-join exporter secret matches ts-mls byte-for-byte.
- Amethyst decrypt() parses the RFC 9420 §6.3.1 PrivateMessageContent
framing (application_data<V> + FramedContentAuthData.signature<V> +
zero padding) and verifies the sender's FramedContentTBS signature
against Alice's leaf, for all three ciphertexts.
https://claude.ai/code/session_01HfHdd5S5rvxUW2ihEpLGJr
Add a Rust generator under quartz/tools/mdk-vector-gen that emits a
Welcome, joiner KeyPackage, committer signer_pub, joiner's three
private keys, and a post-join MLS-Exporter KAT, using the same
openmls 0.8 backend MDK / whitenoise use. Commit its output at
quartz/src/commonTest/resources/mls/mdk-welcome.json.
MdkWelcomeInteropTest consumes the vector and proves Amethyst can:
- parse a KeyPackage OpenMLS authored and verify its self-signature;
- run the joiner's processWelcome end-to-end (HPKE unwrap of group
secrets, welcome-key derivation, AEAD GroupInfo decrypt, ratchet
tree decode, signer leaf lookup, GroupInfoTBS Ed25519 verify);
- derive MLS-Exporter("marmot", "group-event", 32) byte-for-byte
identically to openmls — the exact exporter Marmot uses for the
outer ChaCha20 wrap on kind:445 events.
testBobDecryptsMdkApplicationMessagesFromAlice is @Ignored with a
detailed TODO because Amethyst's MlsGroup.encrypt/decrypt skip the
RFC 9420 §6.3.1 PrivateMessageContent framing (application_data<V> +
FramedContentAuthData + padding). Amethyst ↔ Amethyst works (both
sides omit it) but every cross-implementation PrivateMessage fails.
Tracked as a follow-up.
https://claude.ai/code/session_01HfHdd5S5rvxUW2ihEpLGJr
Import the canonical IETF MLS test vectors from mlswg/mls-implementations
to verify wire-format compatibility with OpenMLS and mls-rs. These are
the same test vectors used by both Rust implementations for cross-
implementation interop validation.
Phase 1 (Foundations):
- crypto-basics.json: RefHash, ExpandWithLabel, DeriveSecret,
DeriveTreeSecret, SignWithLabel, EncryptWithLabel
- tree-math.json: Binary tree arithmetic for all tree sizes
- key-schedule.json: Full 12-secret epoch key derivation chain
- secret-tree.json: Per-sender handshake/application ratchet keys
Phase 2 (Wire Format):
- messages.json: Round-trip serialization of all MLS message types
- message-protection.json: PublicMessage/PrivateMessage framing
- transcript-hashes.json: Confirmed/interim transcript hash computation
Phase 3 (TreeKEM):
- treekem.json: UpdatePath processing, path secret derivation
- tree-validation.json: Tree hash and resolution verification
- tree-operations.json: Add/remove/update proposal application
- welcome.json: Welcome message deserialization
Phase 4 (End-to-End Protocol):
- passive-client-welcome.json: Join via Welcome, follow epochs
- passive-client-handling-commit.json: Process varied commit types
- passive-client-random.json: Randomized multi-epoch scenarios
Initial test results reveal ExpandWithLabel encoding discrepancy
in HkdfLabel context field that cascades to most crypto operations.
Tree math tests pass fully. These findings demonstrate the value of
importing standard interop vectors.
https://claude.ai/code/session_01NocQDWj2Y92FugjfgazzL3
Claude