zeekay
df80db06b3
The embedded threshold dispatcher's Sign_Ctx_Profile consults a
thresholdd.ChainProfileResolver before allowing the single-party dealer
shortcut on ctx-bound signing (pulsar/magnetar sign_ctx). mpcd built the
ZapServer with NO resolver, so the gate fell to its documented fail-OPEN
branch — every chainID, strict-PQ chains included, slipped the gate.
Wire the node's chain-profile posture into the dispatcher BEFORE Start:
- --chain-profile (MPC_CHAIN_PROFILE), default strict-pq → fail-closed.
Any non-empty chainID not allow-listed resolves to ProfileStrictPQ and
the dealer shortcut is REFUSED.
- --legacy-chains (MPC_LEGACY_CHAINS): explicit allow-list of chainIDs
permitted the shortcut (dev / non-PQ chains co-served by a strict node).
Resolver is the canonical thresholdd.NewStaticChainProfileResolver — no
bespoke type, no luxfi/consensus/config dependency.
Residual: thresholdd.RefuseUnderStrictPQ short-circuits empty chainID to
PASS before consulting the resolver; that short-circuit lives inside the
threshold gate (threshold owns the listener, read-only here). The resolver
wired here is already fail-closed for "" (ResolveChainProfile("") ==
ProfileStrictPQ), so the residual closes the instant the threshold gate
routes "" through the resolver — a one-line change in
threshold/pkg/thresholdd/profile.go (drop `|| chainID == ""`).
Tests: TestStrictPQGate_FailClosed / _LegacyDefaultPermissive drive the
real gate proving refuse-by-default + allow-list opt-out + empty/unknown
fail-closed at the resolver boundary.
Also drops the stale "bls" scheme from the dispatcher start log (BLS
custody was ripped in H-2).
mpcd — MPC Daemon
mpcd is a threshold-signature daemon. It speaks ZAP wire protocol over
TLS 1.3 directly between peers — no NATS, no Consul, no PostgreSQL in the
critical path. The daemon is the same binary in every deployment shape;
the operating mode is selected entirely by flags.
Operating modes
There is exactly one start command (mpcd start) and the topology is
determined by the --peer and --threshold flags:
| Topology | Flags | Use |
|---|---|---|
| Standalone (1-of-1 self-loop) | --threshold 1 (no --peer) |
Smoke tests, dev sandbox |
| Networked t-of-n cluster | --threshold t --peer ... (n−1 peers) |
Production |
In all cases mpcd runs the consensus-embedded transport
(pkg/transport). The "consensus" here is local PoA membership over the
node's own Ed25519 identities — it is intentionally not the Lux mainnet
chain, because key shares must never leave the cluster.
Standalone (1-of-1)
mpcd start \
--node-id solo \
--listen :9999 \
--api :9800 \
--data /var/lib/mpcd \
--threshold 1
Starts mpcd with itself as the only quorum member. /healthz will report
signing_quorum: true immediately. Keygen and signing of fresh wallets
require ≥2 parties — CGGMP21 and FROST cannot produce shares with a
single party — so this mode exists only for boot-up smoke tests, e2e
harness fixtures, and verifying TLS / membership / API plumbing. For real
signing, run a multi-node cluster.
Networked (t-of-n)
# Node 0
mpcd start --node-id node0 --listen :9999 --api :9800 \
--data /data/node0 --threshold 2 \
--peer [email protected]:9999 --peer [email protected]:9999
# Node 1
mpcd start --node-id node1 --listen :9999 --api :9800 \
--data /data/node1 --threshold 2 \
--peer [email protected]:9999 --peer [email protected]:9999
# Node 2 — same pattern
The daemon expects the cluster size n = len(peers) + 1 and rejects start
when threshold > n. See pkg/transport/registry.go::HasSigningQuorum for
the quorum arithmetic.
Smoke test
go test -tags=integration ./cmd/mpcd/... -count=1 -timeout 90s
standalone_test.go builds mpcd, runs it with --threshold 1 on free
ports and a fresh data directory, polls /healthz until quorum holds,
and asserts the response shape. It does not exercise keygen — see e2e/
for that.