Solana addresses were correct and receive-only: ConsensusKeyInfoStore.Save was
the only RegisterKey caller and hardcoded "secp256k1", and TriggerSign read the
curve from that field, so no product entry point could reach Ed25519 signing.
The hardcode is not fixed, it is UNREPRESENTABLE. transport.KeyInfo.KeyType is
deleted — the record carries one public key per curve and a PublicKeyFor(curve)
— and RegisterKey lost its keyType parameter, so there is no longer a place to
state a curve wrongly. A scalar KeyType was the wrong shape anyway: one keygen
ceremony produces BOTH a secp256k1 and an Ed25519 key, so "what curve is this
wallet" has no single answer.
The request carries the network instead, and ONE table maps it to a curve, with
NO default arm — KeyTypeForNetwork returns ErrUnknownNetwork rather than
guessing. That is the point: the old default returned secp256k1 for anything
unrecognized, which is how a Solana request would have been signed with the
wrong key.
/sign's 32-byte clamp becomes the SCHEME's rule rather than the endpoint's:
secp256k1 signs a digest and requires exactly 32 bytes, Ed25519 signs the
message at any length. /sign no longer accepts key_type at all — two ways to say
the curve is the misuse being removed — and Network is bound into the
idempotency fingerprint, so the same bytes for SOL and ETH conflict instead of
sharing one cached signature from a different key.
⚠ The trap this nearly shipped with: every pre-existing KeyInfo record has EMPTY
public keys, because the old Save wrote "", "". A naive "does this wallet have
this curve" gate would have refused every existing wallet on every curve. The
check is gated on RecordsCurves() — a record naming no curve denies none, and
the missing share stays the thing that fails closed.
Verified end to end, not by mirroring: a Solana request through
ConsensusMPCBackend.TriggerSign with a real 2-of-3 FROST ring produces a
signature crypto/ed25519.Verify accepts, over a 63-byte message so any
reintroduced clamp or pre-hash fails it; ETH/EVM/BTC/LUX still route to
secp256k1 and must RECOVER to the wallet's key. Four mutations tried, all
caught.
Behavioral risk worth naming: an unrecognized chain string now fails its
transaction closed rather than signing with a default. That is correct, and the
real fix is validating chain at POST /v1/transactions.
Adds the topology contract that lets a fund run mpcd as its own private
cluster — no Lux primary network registration, no shared M-Chain audit
ledger — using the same code path and the same operator surface.
Mode flag at cmd/mpcd/main.go:
--network=primary|private # registration target
--audit-store=mchain|local-worm|... # audit log destination
--registrar-url, --registrar-auth # primary-mode announcement
--audit-worm-path, --audit-mchain-url # backend selectors
pkg/audit:
- Append-only Merkle hash chain. Tampering with any historical event
invalidates every subsequent hash. Canonical bytes use fixed-order
concatenation (json.Marshal map ordering is non-deterministic).
- WORMDispatcher: NDJSON append, replay-on-start, fsync per Append.
- MChainDispatcher: batched POST of (batchHash, fromSeq, toSeq) to a
configurable anchor RPC.
- compositeDispatcher: fan-out to multiple legs with per-leg sealing.
- S3 Glacier Vault / Azure Immutable / GCS Object Lock dispatchers
fail closed — wired into the flag surface but gated behind the
cloud-audit build tag, no silent fallback.
pkg/identity/bootstrap.go: identity creation + (primary-mode only)
registrar announcement. Same on-disk format as the previous
loadOrGenerateIdentity (which is now removed); private mode is silent.
deployments/k8s-private: fund-only Kustomize overlay. Standalone
namespace, NetworkPolicy that blocks egress to anything outside the
fund's VPC, hardware-WORM PVC for the audit log, KMS-driven secret
template.
deployments/k8s-primary: env-var patch overlay on the existing lux-mpc
base. composite(local-worm,mchain) by default.
deployments/terraform/{aws,gcp,azure}: VPC + audit storage modules.
terraform validate passes; EKS/GKE/AKS + HSM modules are stubbed and
not yet plan-tested.
deployments/onprem/README.md: WORM storage + PKCS#11 HSM checklist.
Tests (14 total, all passing):
pkg/audit: 6/6 (chain, WORM replay, MChain batching, composite,
cloud stubs fail loud, double-seal rejected)
pkg/identity: 4/4 (private no-call, primary call, primary empty
URL no-op, primary registrar 503 surfaces)
internal/privatemode: 4/4 (no registrar traffic, restart, tamper-detect,
cloud stubs fail loud)
Companion runbook in lux/papers/lux-private-mpc-deployment/
(LaTeX, 5 pages, tectonic-clean).
zeekay