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zeekay
70e0899973
Closes Blue audit B4. Four nonce-binding gaps in the ReleaseGate are
closed in one pass:
1. Nonce derivation is now HMAC-SHA256(rootKey, "kms/release/v1" ||
epoch || jobID || rand32). A nonce issued for jobID A cannot be
replayed under jobID B even if the random component is identical.
2. Issue() persists (jobID, nonce, epoch, expires) in a NonceStore.
Release() looks up the stored nonce and constant-time-compares it
against req.Nonce. The forged-nonce path now refuses with
ErrNonceMismatch instead of silently accepting any 32 bytes.
3. AAD now binds the issued nonce: epoch || jobID || teePub || nonce.
Two Release() calls with the same (epoch, jobID) but different
issuances produce distinct AADs; sealed keys are non-fungible
across issuances even after a process restart.
4. State (epoch + pending nonces + consumed-set) is durable via the
NonceStore interface. Two implementations:
- MemoryNonceStore for tests / single-shot dev
- DatabaseNonceStore for prod (luxfi/database; pair with encdb +
ZapDB for at-rest encryption per Hanzo Base pattern)
Replay window default 1h; pending TTL 1h. GC reclaims both.
Tests cover all five required scenarios + nonce-binding + AAD-binding
asserts. -race clean.
Backwards-incompatible change to NewLocalReleaseGate / NewMPCReleaseGate
/ NewHSMReleaseGate signatures; no compat shim per audit guidance.