Files
consensus/pkg
zeekayandHanzo Dev ac10e53f84 cert: give the export rung a floor on the SET, so a shrinking denominator cannot shrink past a committee
Reading both floors over the signers let a set shrink to its signers, and a rung
whose floors are read over n is satisfiable at every n. TwoThirdsCount(1) is 1, so
one signature over a one-signer set clears the count floor and the stake floor
together and mints export finality. Byzantine tolerance is f = ⌊(n−1)/3⌋, which is
ZERO for n of one, two and three: such a certificate absorbs no fault at all, and
one compromised key among its signers forges it outright.

So the export rung refuses a signing set below minBFTCommittee — the same constant
bftCommittee floors committee SELECTION at, read at the certificate instead of at
the sampler, and reused rather than restated. It is a floor on the SET, stated
beside the n<1 refusal because neither quorum floor implies it: both are read over
n and both shrink with it. Nova has no such clause and must not grow one — it
authorizes local execution the chain can still reorg away, so a small or
partitioned chain has to be able to make progress. A three-validator chain now
PRODUCES and never CERTIFIES; operators need n ≥ 4 to export with any fault
tolerance. Rust mirrors it as CertError::MinCommittee, which the corpus vocabulary
folds into Go's one belowThreshold class.

The transcription guard was reading the wrong denominator. verdict_test computed
n as len(c.Set), the membership ROLL, so a floor moved onto the roll would agree
with the guard and be re-blessed by -update — the second line of defence agreeing
with the regression it exists to catch. It now counts the seats that hold a key,
on the Quasar branch and the Nova one, and transcribes the committee floor as a
search for the least n whose fault budget reaches one rather than as the constant.
Proven by construction: with the corpus source reporting the roll as its signer
count and the golden re-blessed, the old guard passes and the new one fails.

The corpus could not have caught it either. quasar_keyless_third had three signers
on a roll of four, and ⌊2·3/3⌋+1 and ⌊2·4/3⌋+1 are both three, so its count half
was vacuous. Two rows now separate the denominators one at a time:
quasar_keyless_stake (six signers, a seventh member holding a third of the roll —
the count floor is five either way, so only stake decides) and
quasar_keyless_count (four signers, two members holding one unit each — the stake
clears under either reading, so only the count decides). TestKeylessRowsBind-
BothDenominators fails if either is lost or flattened.

quasar_keyless_third itself FLIPS to a refusal, and it is the row that states the
new clause: the recorded stake floor is 200 over the three hundred that can sign
and not 333 over the five hundred the chain carries, so the denominator IS the
signers — and the certificate is refused anyway, on neither quorum floor. Reading
the floors over the signers stops a spectator stranding a chain; it is not a way
for a chain with three signers to export. Every other frozen verdict is
byte-identical, and the admission section and the signed vectors are untouched.

StakeSource gains CarriedStake, and no floor may read it. SignerStake alone
decides a certificate correctly and cannot show the set shrinking underneath one:
a chain whose signable stake has fallen to a sliver of what it carries still
certifies at ⅔ of the sliver, and ResponsiveStakePct — voted over signer — stays
at one the whole way down. FinalityStatus.SignerStakePct is the number that falls,
and the one to alarm on. Rust has carried(), C++ has total_stake(); Go had lost
the projection when the denominator moved.

Co-authored-by: Hanzo Dev <[email protected]>
2026-09-01 20:52:28 -07:00
..

Lux Consensus Source Code Organization

This directory contains implementations of the Lux consensus framework in multiple programming languages. Each language implementation provides the same consensus algorithms with language-specific optimizations and idioms.

Directory Structure

src/
├── c/          # C implementation (high-performance, minimal overhead)
├── cpp/        # C++ implementation with MLX extensions (GPU acceleration)
├── go/         # Go implementation (production blockchain integration)
├── python/     # Python implementation (research and prototyping)
└── rust/       # Rust implementation (memory-safe systems programming)

Language Implementations

Go (/src/go/)

  • Status: Production-ready
  • Use Case: Core blockchain node integration
  • Import Path: github.com/luxfi/consensus (via go.work at root)
  • Features: Full integration with Lux node, concurrent processing

C (/src/c/)

  • Status: Data structures only — not real consensus (per SDK audit)
  • Use Case: Embedded systems, performance-critical applications
  • Features: Minimal dependencies, ZeroMQ networking, SIMD optimizations

Rust (/src/rust/)

  • Status: FFI wrapper around the C library — inherits C limitations, not native consensus (per SDK audit)
  • Use Case: Memory-safe systems, async applications
  • Features: Zero-cost abstractions, async/await, compile-time guarantees

Python (/src/python/)

  • Status: Research/Development
  • Use Case: Prototyping, research, data analysis
  • Features: NumPy integration, ML frameworks, visualization

C++ (/src/cpp/)

  • Status: Development
  • Use Case: High-performance with GPU acceleration
  • Features: MLX extensions, template metaprogramming, SIMD/GPU support

Building

From the repository root:

# Build all implementations
make build

# Build specific language
make build-go
make build-c
make build-rust
make build-python
make build-cpp

Testing

From the repository root:

# Test all implementations
make test

# Test specific language
make test-go
make test-c
make test-rust
make test-python
make test-cpp

Consensus Engines

All implementations support these consensus engines (Quasar family):

  1. Wave - Threshold voting with fast probabilistic consensus (production)
  2. Nova - Linear chain consensus (wraps Ray sub-protocol)
  3. Nebula - DAG consensus with safe-prefix commit (wraps Field sub-protocol)
  4. PostQuantum - Quantum-resistant consensus with BLS + Pulsar + ML-DSA
  5. Chain - Linear chain consensus for ordered blocks
  6. DAG - Full directed acyclic graph consensus

Performance Benchmarks

Implementation Votes/Second Memory Usage Latency
C 14,000+ < 10 MB < 1ms
Rust 13,500+ < 15 MB < 1ms
Go 12,000+ < 20 MB < 2ms
C++ (w/ MLX) 15,000+ < 25 MB < 1ms
Python 5,000+ < 50 MB < 5ms

Note. These per-implementation votes/sec figures are unverified and, per the SDK audit, several measure data-structure insertion on stub/wrapper SDKs (C = data structures only, Rust = FFI wrapper over C, C++ = Wave-only stub); only the Python SDK implements real consensus. Treat as illustrative, not measured consensus throughput. See .github/workflows/README.md and the "Honest Assessment" block in LLM.md.

Protocol Compatibility

All implementations use the same binary protocol for network communication:

┌─────────────┬────────────┬──────────┬───────────┬──────────┐
│ Engine Type │ Node ID    │ Block ID │ Vote Type │ Reserved │
│ (1 byte)    │ (2 bytes)  │ (2 bytes)│ (1 byte)  │ (2 bytes)│
└─────────────┴────────────┴──────────┴───────────┴──────────┘

This ensures interoperability between different language implementations.

Development Guidelines

  1. Consistency: All implementations should provide the same consensus guarantees
  2. Testing: Each implementation must have comprehensive test coverage
  3. Documentation: Language-specific documentation in docs/{language}/
  4. Performance: Optimize for language strengths while maintaining correctness
  5. Compatibility: Maintain protocol compatibility across all implementations

Contributing

When adding features or fixes:

  1. Implement in the reference implementation (Go)
  2. Port to other languages maintaining consistency
  3. Add tests for all implementations
  4. Update documentation

See CONTRIBUTING.md for detailed guidelines.

License

Copyright (C) 2019-2025, Lux Industries Inc. All rights reserved.