Files
consensus/pkg/rust
zeekayandHanzo Dev 82ab92a70f cert: give the export rung a distinct-signer floor, so two thirds means two thirds of the parties
The Quasar rung read only stake. Two thirds of the stake is one signature
wherever two thirds of the stake is one validator, so a whale holding a
supermajority could mint an export-grade certificate alone — and export-grade
finality is what a bridge, a settlement and a cross-chain message admit on. A
certificate one key can produce is not a claim that a Byzantine supermajority
agreed, however much weight stands behind the key.

VerifyWeighted now demands config.TwoThirdsCount(n) = floor(2n/3)+1 DISTINCT
signers of a Quasar certificate as well as the stake. Two independent
predicates, neither sufficient alone, the same shape Nova has one rung up.

TwoThirdsCount is the count that value has always been, given its own name and
one home. It is derived from TwoThirdsStakeFloor over unit weights rather than
restated, so the count and the stake predicate cannot drift. It replaces three
spellings of the same closed form that had grown apart in reach if not yet in
value: config.EqualStakeSupermajorityThreshold (the alpha sizer), the private
chain.quasarQuorum (the attestor's assembly trigger), and the clause that was
missing from the verifier entirely.

Stake is read first and the count second. Both must hold, so the order names
only which clause a refusal reports: on an equal-stake set the two are one bar
in two units and bind together, and the count clause binds ALONE only where the
weights are lopsided — so reaching it means the stake was there and the signers
were not. Every verdict the R3 corpus froze is unchanged.

Liveness. Nothing that exports today stops exporting. QuasarAttestor, the only
producer of export certificates, already assembled at exactly floor(2n/3)+1
attestations, and FeasibleParams already sized alpha — the floor
HandleIncomingCert applies to a gossiped Quasar cert — to the same number.
Producer, gossip door and verifier now read one function, so the verifier's new
clause refuses nothing the engine can build and exactly what it never could.
quasar_count_floor_test.go holds all three to that.

The tests that moved were the ones written on three seats, where floor(2n/3)+1
is three and no two-signer certificate can isolate the stake half any more.
They ask the same question on four.

Rust: the same clause in Cert::verify_quasar_supermajority, the same name.
1.22.4 -> 1.22.5 — this changes what the crate accepts.

Also, at the already-admitted door: the zero-weight refusal is justified by
agreement with Register, not by the phantom-signer argument alone. A seat whose
key does not decode can never sign and is refused anyway, because the weight is
read before the key is — and deferring it would make admission depend on which
keys a node's crypto build can parse.

Co-authored-by: Hanzo Dev <[email protected]>
2026-09-01 17:39:39 -07:00
..

lux-consensus

Pure-Rust SDK for the Lux Quasar consensus stack — Wave threshold voting, FPC (Fast Probabilistic Consensus), Photon validator sampling, Focus confidence accumulation, and post-quantum hybrid finality via BLS12-381 + Pulsar (Module-LWE threshold, FIPS 204 byte-equal).

Features

Flag What it pulls in
default CPU-only, no extra deps beyond blst and hex
simd blake3 (SIMD hashing) + rayon (data-parallel vote tally)
mlx Apple Silicon GPU acceleration via mlx-sys (implies simd)
cuda NVIDIA GPU acceleration (implies simd) — work in progress
gpu mlx + cuda — auto-select per platform

Usage

use lux_consensus::*;

let config = QuasarConfig::mainnet();
let mut engine = QuasarEngine::new(config);
engine.start().unwrap();

let block = Block::new(
    ID::from([1u8; 32]),
    ID::from([0u8; 32]),
    1,
    b"Hello, Lux!".to_vec(),
);
engine.add(block.clone()).unwrap();

// A validator is named by its 20-byte NodeID — never the 32-byte block id.
for i in 0..20 {
    engine.add_validator(NodeID::from([i; 20]), 1).unwrap();
}

for i in 0..20 {
    let vote = Vote::new(block.id.clone(), VoteType::Preference, NodeID::from([i; 20]));
    engine.record_vote(vote).unwrap();
}

assert!(engine.is_accepted(&block.id));
engine.stop().unwrap();

Architecture

  • Wave — adaptive-threshold voting driven by FPC outputs
  • FPC — PRF-derived per-round thresholds for fast probabilistic consensus
  • Photon — luminance-tracked validator sampling
  • Focus — β consecutive rounds of confidence before commit
  • Quasar — a two-thirds-by-stake certificate: the distinct signed accepts themselves, each checked against its own signer's key

License

Lux Ecosystem License 1.2 — see the LICENSE file.