zeekayandHanzo Dev
b19863787b
The signing sessions emitted a raw, possibly high-S S with a recovery byte that was then dropped at every serialization boundary. luxfi/evm ecrecover rejects a high-S signature (EIP-2 "invalid sender"), and without a propagated recovery id a caller must guess v (wrong guess => wrong sender). This is what broke the KMS /sign output. - signing_session.go + signing_session_lss.go: produce the signature through the shared threshold helper s.signature.SigEthereum() (EIP-2 low-S + recovery id in ONE place), then self-verify the recovery id against the wallet's own public key via CalculateRecoveryByte and FAIL CLOSED on mismatch — never emit a signature that binds to the wrong address. - pkg/api SignResult: carry V (recovery id "0"/"1"). - cmd/mpcd TriggerSign: propagate V from the signing session's signature_recovery and assemble the canonical 65-byte r‖s‖v so KMS /sign never returns an empty signature. - handlers_kms REST: include v in the response. Requires the non-mutating, tested SigEthereum in threshold v1.12.4; bumps luxfi/threshold v1.12.0 -> v1.12.4 (MVS pulls its transitive updates). Builds GOWORK=off; pkg/api + pkg/mpc tests green. Co-authored-by: Hanzo Dev <[email protected]>
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.