zooqueen
df4791d374
serveReveal returning an error aborted startup, so a new capability could stop a ring from doing the thing it already existed to do. Signing was working before openings were possible and should keep working when one is not. Nothing is hidden by carrying on. The failure is logged here, and an opening that goes short already reports how many answered out of how many it needed — which is the number that matters and the place someone is looking when it does.
MPC
Threshold signing engine -- CGGMP21 (ECDSA), FROST (EdDSA/Schnorr), BLS, SR25519, and post-quantum lattice signatures (Pulsar M-LWE, Corona R-LWE, and double-lattice composition) via the embedded thresholdd dispatcher. No full private key reconstruction, ever.
go get github.com/luxfi/mpc
Architecture
luxfi/mpc is a production MPC node (mpcd) that performs distributed key generation and threshold signing across a cluster. Each node holds a key share; t of n nodes must cooperate to produce a signature. The full private key never exists on any single machine, in memory or on disk.
Protocols
| Protocol | Curve / Lattice | Key Type | Use |
|---|---|---|---|
| CGGMP21 | secp256k1 | secp256k1 |
Bitcoin, Ethereum, Lux C-Chain, all EVM L2s, XRPL |
| FROST | Ed25519 | ed25519 |
Solana, TON, Polkadot, Cardano, Substrate chains |
| BLS | BLS12-381 | bls |
Lux consensus, beacon chain, aggregated signatures |
| SR25519 | Ristretto255 | sr25519 |
Substrate/Polkadot native |
| Pulsar | M-LWE (FIPS 204 / ML-DSA-65 threshold) | pulsar |
Post-quantum threshold signing — bridge anchors, strict-PQ profile |
| Corona | R-LWE (Corona) | corona |
Post-quantum threshold signing — orthogonal lattice family to Pulsar |
| Double-lattice | Pulsar ⊕ Corona | double-lattice |
Composed u32_be(len) ‖ pulsar_sig ‖ corona_sig — both must verify |
Pulsar, Corona, and double-lattice are exposed via the embedded
threshold dispatcher (--threshold-listen, default 127.0.0.1:7300),
which is luxfi/threshold/pkg/thresholdd. The dispatcher is a JSON-RPC
2.0 surface shared with cggmp21 / frost / bls — one wire, six
schemes — and is consumed by the teleport bus
(~/work/lux/teleport/mpc/src/signers/). The wire format is documented
in ~/work/lux/threshold/CLAUDE.md under "thresholdd — unified
JSON-RPC daemon".
Validator key slots vs. engine protocols (truthful naming). The KMS validator-key API (
pkg/api/handlers_kms.go; hanzo KMS) provisions two slots per validator whose NAMES do not describe their cryptography: the "bls" slot is secp256k1 signed via CGGMP21 threshold ECDSA — NOT bls12-381 aggregation — and the "corona" slot is ed25519 signed via FROST — NOT the Corona R-LWE lattice protocol and NOT post-quantum. The bls12-381, Pulsar/Corona lattice, and double-lattice schemes in the table above arethresholddengine capabilities, not the validator-custody path. Lux consensus BLS is a native per-validator bls12-381 key (PoP + aggregation), never threshold-custodied by this service.
Threshold Model
t >= floor(n/2) + 1
A 2-of-3 cluster tolerates 1 compromised or offline node. A 3-of-5 cluster tolerates 2. The threshold is configurable at key generation time.
Transport Modes
Consensus (default): Peer-to-peer ZAP protocol with built-in PoA consensus. No external dependencies. Nodes discover each other via --peer flags. This is the production path.
Legacy: NATS pub/sub + Consul service discovery. Deprecated but still supported via --mode=legacy.
Packages
cmd/mpcd/ Daemon binary (CLI, API server, node lifecycle)
pkg/mpc/ Core MPC node -- session management, key generation, signing
keygen_session.go CGGMP21 distributed key generation
signing_session.go CGGMP21 threshold signing (secp256k1)
signing_session_frost.go FROST threshold signing (Ed25519)
bls_keygen_session.go BLS key generation
bls_signing_session.go BLS threshold signing
sr25519_keygen_session.go SR25519 key generation
sr25519_signing_session.go SR25519 threshold signing
reshare_session.go Key resharing (rotate shares without changing public key)
recovery.go Key share recovery
tfhe_session.go FHE threshold decryption sessions
pkg/api/ HTTP API (key generation, signing, key info, health)
pkg/transport/ P2P transport (consensus mode ZAP, legacy NATS)
pkg/messaging/ PubSub abstraction over transport layer
pkg/db/ Key share storage (SQLite default, PostgreSQL optional)
pkg/kvstore/ Encrypted key-value store (AES-256, age encryption)
pkg/keyinfo/ Key metadata management
pkg/identity/ Node identity (Ed25519 keypair, mutual authentication)
pkg/backup/ Encrypted periodic backups
pkg/encryption/ AES-256-GCM encryption for key material at rest
pkg/kms/ KMS integration for secret management
pkg/hsm/ HSM provider abstraction (env, AWS, GCP)
pkg/client/ Go client library for MPC API
pkg/event/ Event types (keygen, sign, reshare)
pkg/eventconsumer/ Event processing pipeline
pkg/protocol/ Wire protocol messages
pkg/settlement/ Trade settlement signing
pkg/smart/ Smart contract transaction construction
pkg/custody/ Custody policy engine
pkg/integrity/ Key share integrity verification
pkg/txtracker/ Transaction lifecycle tracking
Security Properties
- Key shares encrypted at rest with AES-256-GCM (key from HSM/KMS)
- Inter-node messages authenticated with Ed25519 signatures
- No key share leaves the node unencrypted
- Resharing rotates shares without changing the public key or requiring all nodes
- Backup files encrypted with age (modern, audited encryption)
- Secret key bytes zeroed from memory after use (
pkg/mpc/secret.go)
Quick Start
Consensus Mode (recommended)
# Node 0
mpcd start --node-id node0 --listen :9999 --api :9800 \
--threshold 2 --peer node1:9999 --peer node2:9999
# Node 1
mpcd start --node-id node1 --listen :9999 --api :9801 \
--threshold 2 --peer node0:9999 --peer node2:9999
# Node 2
mpcd start --node-id node2 --listen :9999 --api :9802 \
--threshold 2 --peer node0:9999 --peer node1:9999
Generate a Wallet
curl -X POST http://localhost:9800/v1/keygen \
-H "Content-Type: application/json" \
-d '{"wallet_id": "w-001", "key_type": "secp256k1"}'
Sign a Transaction
curl -X POST http://localhost:9800/v1/sign \
-H "Content-Type: application/json" \
-d '{"wallet_id": "w-001", "message": "0xdeadbeef...", "key_type": "secp256k1"}'
Go Client
import "github.com/luxfi/mpc/pkg/client"
c := client.New("http://localhost:9800")
result, err := c.CreateWallet("w-001", "secp256k1")
sig, err := c.Sign("w-001", txHash, "secp256k1")
Configuration
config.yaml or environment variables (config keys uppercased — Viper AutomaticEnv):
mode: consensus
environment: local # mainnet | testnet | local
mpc_threshold: 2
max_concurrent_keygen: 2
db_path: "." # SQLite (default), or postgres:// URL
backup_enabled: true
backup_period_seconds: 300
backup_dir: backups
All secrets are sourced from KMS via --hsm-provider=env|aws|gcp. No plaintext secrets in config.
Deployment
Docker Compose
docker compose up
Kubernetes
cd k8s && kubectl kustomize . | kubectl apply -f -
K8s manifests are in k8s/ with Kustomize overlays. Production deployment uses cloudbuild.yaml for CI/CD to GHCR.
Testing
go test ./... # 331 test functions
# End-to-end (3-node cluster)
cd e2e && make test
Papers
- Lux Threshold MPC -- protocol specification, security proofs
- Lux LSS MPC -- linear secret sharing in MPC
- Lux Validator MPC -- MPC integration with validator nodes
- Lux HSM Boundary -- HSM trust boundary analysis
- Lux FHE MPC Hybrid -- FHE threshold decryption via MPC
- Lux M-Chain MPC -- MPC chain architecture
Dependencies
luxfi/threshold-- CGGMP21 and FROST protocol implementationsluxfi/fhe-- FHE threshold decryption sessionsluxfi/hsm-- HSM abstraction layerhanzoai/base-- Application framework
License
Lux Ecosystem License v1.2. See LICENSE.