Claude
91f5d21cc3
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
37 lines
1.6 KiB
Markdown
37 lines
1.6 KiB
Markdown
# mdk-vector-gen
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Rust helper that emits MLS interop test vectors from the same openmls 0.8
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backend MDK/whitenoise uses. Produces `quartz/src/commonTest/resources/mls/mdk-welcome.json`,
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which [`MdkWelcomeInteropTest`] consumes to prove Amethyst can parse and
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decrypt a Welcome + application messages authored by the Rust side.
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## What the vector contains
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- `joiner.init_priv` / `encryption_priv` / `signature_priv` / `signature_pub` —
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all the private key material the joiner needs to drive
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`MlsGroup.processWelcome`.
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- `joiner.key_package` (MlsMessage-wrapped) and `key_package_raw`.
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- `welcome` (MlsMessage-wrapped) — Alice's Welcome for Bob.
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- `committer.signer_pub` — Alice's Ed25519 signature public key.
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- `exporter.{label,context,length,secret}` — `MLS-Exporter("marmot",
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"group-event", 32)` derived from Bob's post-join state. This is the
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exporter Marmot uses to derive the outer ChaCha20 key for kind:445
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events, so a match here means Amethyst's whole post-join key schedule
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agrees with openmls byte-for-byte.
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- `app_messages_alice_to_bob[]` — Alice-sent PrivateMessage bytes plus
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the expected plaintext. (Amethyst decrypt currently skips
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`PrivateMessageContent` framing; the matching test is `@Ignore`d
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until that is fixed.)
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## Regenerating
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```
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cd quartz/tools/mdk-vector-gen
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cargo run --release > ../../src/commonTest/resources/mls/mdk-welcome.json
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```
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The generator uses fresh randomness each run, so the committed vector
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changes on regeneration — that is fine because the Kotlin test only
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asserts round-trip correctness against whatever is in the JSON. Commit
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the regenerated file if you change the generator.
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