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zeekayandHanzo Dev
4256fb283c
a749cfc6 closed a real window and its commentary said it closed THE window. It did not.
Review reproduced the identical symptom arriving through a second, far wider one, and
that one is the more likely production cause precisely because it is wider.
W2: from the cert freezing in assembleCertLocked to finalizedByCert being set — an
interval spanning ApplyCert AND the whole of VM.Accept, i.e. the EVM state write.
Throughout it the block is STILL PENDING, so handleVote never consults finalizedByCert
or acceptedPos at all. The vote lands in pending.certVotes, assembleCertLocked returns
the already-frozen cert, and dropPendingBlockLocked deletes the PendingBlock with the
vote inside it. Remembering the position early does not help: nothing on that path looks
at it. Measured in-window — stillPending=true certFrozen=true certVotes=3
finalizedByCert=false acceptedPosKnown=true — with 4 of 5 voting reading back
ResponsiveStake=0.60 Degraded=true QuasarHeight=0, and re-delivering the identical vote
exports it, so the vote is dropped rather than rejected.
This commit does NOT close W2. Draining pending.certVotes into the attestor at the drop
is its own change with its own review, because ingesting on the pending path naively
emits before the Nova ledger holds the height, and PromoteQuasar then discards the cert.
What it does:
- votesDroppedAtCertFreeze counts signed accept votes that reached certVotes after the
cert froze and are discarded with the PendingBlock, surfaced through Stats() as
votes_dropped_at_cert_freeze. This is the discriminator for a question no green test
suite can answer: 0/40 under 4x CPU contention bounds the flake rate at ~7.5% but
cannot say WHICH window produced it. Non-zero over a few thousand live heights means
W2 fires in production and the drain is required; zero means W1 was the whole story.
- The ordering test's anti-vacuity guard was DEAD — the Fatal above it already returned
on !posAtAccept, so its condition could never hold. Measurement shows the probe
stands at a point strictly EARLIER than the window (pending=true,
finalizedByCert=false), not "exactly the interval that used to be empty" as claimed.
The test remains sound because nothing removes the entry in between, so earlier
implies later — but that is an ordering argument, and it now says so. The guard
pins the probe's location instead, so the argument cannot rot.
- The FourOfFive gate exempted ids.Empty, which is exactly the empty canonical
SyncQuasarFrontier accepts — the one case the check cites as its reason to exist.
Exemption removed.
- Noted at the hoist: acceptedPos is now written unconditionally, where it previously
sat behind promoteQuasar's stake==nil / attestor==nil early returns, so non-attestor
nodes populate it. The ≤1024 sweep is not attestor-gated, so this costs a bounded map.
Co-authored-by: Hanzo Dev <[email protected]>
Lux Consensus
Lux is not merely adding post-quantum signatures to a chain; it defines a hybrid finality architecture for DAG-native consensus, with protocol-agnostic threshold lifecycle, post-quantum threshold sealing, and cross-chain propagation of Horizon finality.
See LP-105 §Claims and evidence for the canonical claims/evidence table and the ten architectural commitments — single source of truth.
Quasar Family of Consensus
Quasar is the consensus engine for the Lux network. It provides unified consensus for linear chains (P-Chain, C-Chain) and DAG chains (X-Chain) with post-quantum finality via three independent cryptographic signing paths.
Sub-Protocols
| Protocol | Role | Package |
|---|---|---|
| Photon | K-of-N committee selection via Fisher-Yates sampling with luminance-weighted reputation | protocol/photon |
| Wave | Per-round threshold voting with FPC (Fast Probabilistic Consensus) | protocol/wave |
| Focus | Confidence accumulation: beta consecutive successes = local finality | protocol/focus |
| Nova | Linear chain consensus mode (P-Chain, C-Chain) -- wraps Ray | protocol/nova |
| Nebula | DAG consensus mode (X-Chain) -- wraps Field | protocol/nebula |
| Prism | DAG geometry: frontiers, cuts, uniform peer sampling | protocol/prism |
| Horizon | DAG order-theory: reachability, LCA, transitive closure, skip lists | protocol/horizon |
| Flare | DAG certificate/skip detection via 2f+1 quorum | protocol/flare |
| Ray | Linear chain finality driver: Wave + Focus + Sink | protocol/ray |
| Field | DAG finality driver: Wave + safe-prefix commit | protocol/field |
| Quasar | BLS + Pulsar + ML-DSA threshold signing, epoch management | protocol/quasar |
Signing Modes
Each cryptographic layer is independently toggleable:
| Mode | Layers | Use Case |
|---|---|---|
| BLS-only | BLS12-381 threshold | Fastest classical consensus |
| BLS + ML-DSA | BLS + FIPS 204 ML-DSA-65 | Dual with PQ identity proof |
| BLS + Pulsar | BLS + Ring-LWE 2-round threshold | Dual with PQ threshold proof |
| BLS + Pulsar + ML-DSA | All three in parallel | Full Quasar (triple mode) |
IsTripleMode() returns true when all three paths are configured.
TripleSignRound1 runs BLS + Pulsar + ML-DSA signing in parallel goroutines.
PQ Mode Selection (Configurable)
The active mode is selectable at runtime via config.PQMode or the
CONSENSUS_PQ_MODE env var. Defined in config/pq_mode.go:
| Mode | Env value | Maps to wire policy |
|---|---|---|
BLSOnly |
bls |
PolicyQuorum |
BLSPlusMLDSA |
bls-mldsa |
PolicyPQ |
BLSPlusCorona |
bls-rt |
PolicyPZ |
BLSPlusGroth16 |
bls-z |
PolicyQuantum (placeholder) |
TripleQuantum |
triple |
PolicyQuantum |
Run bench/pq_modes_bench_test.go for measured per-mode signing /
aggregation / verify costs and cert sizes. Storage and cert size
trade-offs:
| Mode | Sign | Agg | Verify | Cert | Storage 10K |
|---|---|---|---|---|---|
| bls | 312 µs | 8.6 ms | 714 µs | 123 B | 1.17 MB |
| bls-mldsa | 369 µs | 8.5 ms | 3.4 ms | 69 KB | 665 MB |
| bls-rt | 39 ms | 3.3 s | 1.6 ms | 33 KB | 318 MB |
| triple | 40 ms | 3.3 s | 4.3 ms | 102 KB | 981 MB |
Pulsar / triple include the full 2-round Pulsar threshold protocol
(github.com/luxfi/pulsar/threshold — Pulsar is Lux's variant with
DKG2 and Pulsar-SHA3 hash suite). Production parameters M=8, N=7,
LogN=8 (ring degree 256), Q=2^48-ish: classical 2^142, quantum 2^130.
Cert-size floor of ~33 KB is set by the (C, Z, Delta) ring polynomials;
protocol/quasar/cert_size_compare_test.go measures and verifies this.
Architecture
consensus/
protocol/
photon/ Committee selection (Emitter + Luminance)
wave/ Threshold voting + FPC
fpc/ Fast Probabilistic Consensus selector
focus/ Confidence counter (beta tracker)
prism/ DAG cuts, frontiers, uniform sampling
horizon/ DAG reachability, LCA, skip lists
flare/ DAG cert/skip classification (2f+1)
ray/ Linear chain driver (Nova uses this)
field/ DAG finality driver (Nebula uses this)
nova/ Linear chain consensus mode
nebula/ DAG consensus mode
chain/ Block interface primitives
quasar/ BLS + Pulsar + ML-DSA threshold signing
engine/ Consensus engine (Chain, DAG, PQ wrappers)
core/ Core types, DAG structures
types/ Block, Vote, Config, Bag
config/ Parameter presets (single, local, testnet, mainnet)
runtime/ VM wiring (chain IDs, validators, logging)
pkg/wire/ Wire protocol credentials (ML-DSA-44/65/87 + BLS + Ed25519)
bench/ Benchmarks
version/ Re-exports github.com/luxfi/version
Consensus Flow
Linear Chains (Nova)
Photon (select committee) -> Wave (threshold vote) -> Focus (count beta) -> Ray (decide) -> Sink
DAG Chains (Nebula)
Photon (select committee) -> Wave (threshold vote per frontier vertex)
-> Flare (cert/skip) -> Horizon (safe prefix) -> Field (commit ordered prefix) -> Committer
Quasar PQ Finality
After consensus decision, the Quasar signing layer produces threshold certificates:
- BLS: single-round threshold share via
crypto/threshold - Pulsar: 2-round Ring-LWE threshold via
luxfi/corona/threshold - ML-DSA-65: single-round FIPS 204 identity signature
All three run in parallel. A block is quantum-final when all configured certificate layers are valid.
Key Hierarchy
| Layer | Key Type | Purpose |
|---|---|---|
| Node-ID | Ed25519 | P2P transport auth |
| Validator-BLS | BLS12-381 | Classical finality votes |
| Validator-PQ | Pulsar (Ring-LWE) | PQ finality shares |
| Validator-ID | ML-DSA-65 (FIPS 204) | PQ identity attestation |
| Wallet (EVM) | secp256k1 | User transaction signatures |
| Wallet (X-Chain) | secp256k1 | UTXO locking |
Quick Start
import "github.com/luxfi/consensus"
chain := consensus.NewChain(consensus.DefaultConfig())
ctx := context.Background()
if err := chain.Start(ctx); err != nil {
log.Fatal(err)
}
defer chain.Stop()
block := &consensus.Block{
ID: consensus.NewID(),
ParentID: consensus.GenesisID,
Height: 1,
Payload: []byte("Hello, Lux!"),
}
if err := chain.Add(ctx, block); err != nil {
log.Fatal(err)
}
Configuration
// Auto-configure based on validator count
params := consensus.GetConfig(21) // mainnet defaults
// Or use presets
consensus.SingleValidatorParams() // 1 node, dev
consensus.LocalParams() // 5 nodes, local
consensus.TestnetParams() // 11 nodes, testnet
consensus.MainnetParams() // 21 nodes, production
Benchmarks
Measured on Apple M1 Max:
| Component | Operation | Time/Op |
|---|---|---|
| Wave | Vote round | 3.38 us |
| Photon | K-of-N selection | 3.03 us |
| Luminance | Brightness update | 72 ns |
ZAP wire protocol (measured, bench/):
| Configuration | Throughput |
|---|---|
| Single connection | 114K TPS |
| 20 parallel connections | 376K TPS |
| 50 conns + batch 1000 | 20.26M TPS |
Testing
GOWORK=off go test ./...
GOWORK=off go test -bench=. ./bench/
Security Model
- Pre-quantum: Attacker must corrupt >= 1/3 stake to fork
- Q-day (BLS broken): Lattice certificates prevent unsafe finalization
- Post-quantum: Security rests on Module-LWE (Pulsar) + Module-LWE/SIS (ML-DSA)
License
BSD 3-Clause. See LICENSE.