zeekay
cb77fab979
luxfi/threshold v1.12.7 added FROST(Ed25519, SHA-512), so Solana and TON finally have a signable curve. The sessions named "EdDSA" were calling KeygenTaproot — BIP-340 over secp256k1 — whose key is also 32 bytes, sails through the len(EDDSAPubKey)==32 gate, and base58-encodes into a real-looking Solana address the ring can never sign for. ⚠ A LIVE WRONG-ADDRESS BUG went with it: handlers_wallets served addresses["ton"] = *wallet.SolAddress. A TON address is not a base58 pubkey — it is workchain plus a hash of the wallet contract's StateInit, base64url with a CRC16 — so the API was handing out an address that decodes to nothing. Deleted rather than guessed; TON returns when its encoding is real. The keygen tests used to call frost.KeygenEd25519 directly, which validated the LIBRARY and not the daemon: reintroducing KeygenTaproot left every package green. They now go through the production session, and so does a test that constructs the real signing session and proves the caller's bytes reach the protocol unhashed. Both original bugs reintroduced together fail 11 tests. secp256k1 keygen changes from fail-open to fail-closed, and that is the one behavioural change to the existing EVM/BTC path. An empty pubkey previously meant any of nil config, marshal failure, kvstore.Put failure or keyinfo-save failure — and was returned as SUCCESS, announcing addresses while fewer than t+1 nodes hold a share. Applying fail-closed to Solana while leaving the higher-value leg fail-open is incoherent. Also: the KMS share classifier still keyed off the retired "frost:" prefix; the CGGMP21 session published its own local failure onto the same first-wins subject as the ring's verdict, so one node's failure could beat the ring's success; and one 120s deadline shared across two sequential ceremonies starved the cheap leg. NOT YET SPENDABLE. ConsensusKeyInfoStore.Save is the only RegisterKey caller and hardcodes "secp256k1", and TriggerSign reads the curve from that field, so no product entry point can reach Ed25519 signing. The address is correct; signing it needs a wire-contract change shared with lux/wallet.
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.