Lux FHE

Fully Homomorphic Encryption for the Lux Network — Pure Go with optional C++/CUDA acceleration.

Overview

Lux FHE is a production-ready implementation of Fully Homomorphic Encryption (FHE) that enables computation on encrypted data without decryption. Ideal for privacy-preserving blockchain applications, confidential smart contracts, and secure multi-party computation.

Implementations

Mode	Build Flag	Description
Pure Go	CGO_ENABLED=0	Zero dependencies, compiles anywhere Go runs
C++ Optimized	CGO_ENABLED=1	High-performance C++ backend
GPU Accelerated	CGO_ENABLED=1 + GPU	MLX (Apple Silicon), CUDA (NVIDIA)

Pure Go Mode

• Zero external dependencies — compiles anywhere Go runs
• Cross-platform — Linux, macOS, Windows, ARM64
• Deterministic builds — critical for blockchain consensus
• Easy deployment — single static binary

C++/GPU Mode

For maximum performance, build with CGO enabled to use our optimized C++ implementation:

CGO_ENABLED=1 go build ./...

See luxcpp/fhe for C++/CUDA/MLX implementation details.

Blockchain Optimized

• Public key encryption — users encrypt without secret key access
• Deterministic RNG — blockchain-compatible random numbers
• Full serialization — keys and ciphertexts
• FheUint160 — native Ethereum address support
• FheUint256 — native EVM word size support

Performance (Apple M1 Max)

Operation	Pure Go	C++ (CGO)	GPU
Bootstrap Key Gen	132 ms	68 ms	12 ms
Boolean Gate (AND)	51 ms	28 ms	3 ms
8-bit Addition	5.0 s	2.1 s	180 ms

See BENCHMARKS.md for complete performance data.

Installation

go get github.com/luxfi/fhe

Quick Start

package main

import (
    "fmt"
    fhe "github.com/luxfi/fhe"
)

func main() {
    // Setup
    params, _ := fhe.NewParametersFromLiteral(fhe.PN10QP27)
    kg := fhe.NewKeyGenerator(params)
    sk, pk := kg.GenKeyPair()
    bsk := kg.GenBootstrapKey(sk)

    // Encrypt with public key (user side - no secret key needed!)
    pubEnc := fhe.NewBitwisePublicEncryptor(params, pk)
    ctA, _ := pubEnc.EncryptUint64(5, fhe.FheUint8)
    ctB, _ := pubEnc.EncryptUint64(3, fhe.FheUint8)

    // Compute on encrypted data (server/blockchain side)
    eval := fhe.NewBitwiseEvaluator(params, bsk, sk)
    ctSum, _ := eval.Add(ctA, ctB)

    // Decrypt result
    dec := fhe.NewBitwiseDecryptor(params, sk)
    result := dec.DecryptUint64(ctSum)
    fmt.Println("5 + 3 =", result) // Output: 5 + 3 = 8
}

Supported Types

Type	Bits	Use Case
FheBool	1	Boolean flags, comparisons
FheUint4	4	Small counters, nibbles
FheUint8	8	Bytes, small values
FheUint16	16	Short integers
FheUint32	32	Standard integers
FheUint64	64	Large integers
FheUint128	128	UUIDs, large values
FheUint160	160	Ethereum addresses
FheUint256	256	EVM word size

Operations

Arithmetic: Add, Sub, ScalarAdd, Neg

Comparison: Eq, Lt, Le, Gt, Ge, Min, Max

Bitwise: And, Or, Xor, Not, Shl, Shr

Selection: Select (encrypted if-then-else), CastTo

Architecture

github.com/luxfi/fhe/
├── fhe.go               # Parameters, key types, key generation
├── encryptor.go         # Boolean encryption (secret key)
├── decryptor.go         # Boolean decryption
├── evaluator.go         # Boolean gates (AND, OR, XOR, NOT, MUX)
├── bitwise_integers.go  # Integer operations + public key encryption
├── integers.go          # FheUintType definitions
├── integer_ops.go       # Comparison, bitwise operations
├── serialization.go     # Key/ciphertext serialization
├── random.go            # FHE random number generation
├── server/              # HTTP server for benchmarking
└── gpu/                 # GPU acceleration stubs

Dependencies

• github.com/luxfi/lattice/v6 — Lattice cryptography primitives

Running Tests

# All tests (Pure Go)
CGO_ENABLED=0 go test -v ./...

# With C++ backend
CGO_ENABLED=1 go test -v ./...

# Benchmarks
go test -bench=. -benchmem -run=^$

HTTP Benchmark Server

Both Go and C++ implementations include HTTP servers for head-to-head benchmarking:

# Go server
go run ./server -port 8080

# C++ server (see luxcpp/fhe)
./fhe-server --port 8081

License

BSD-3-Clause

Lux FHE is open source software. Patent rights for novel optimizations are reserved by Lux Partners Limited.

• Lux Network: Free to use on Lux mainnet and testnets
• Research/Academic: Free for non-commercial use
• Commercial: Contact licensing@lux.partners

See LICENSE for full terms.

Implementation

Original implementation based on published academic research:

• Built on github.com/luxfi/lattice (our cryptographic primitives)
• Implements peer-reviewed algorithms from academic publications
• Contains novel optimizations developed independently

Academic References:

• Chillotti et al. "FHE: Fast Fully Homomorphic Encryption Over the Torus" (Journal of Cryptology, 2020)
• Ducas & Micciancio "FHEW: Bootstrapping Homomorphic Encryption in Less Than a Second" (EUROCRYPT 2015)

Related Projects

• luxcpp/fhe — C++/CUDA/MLX implementation
• luxfi/lattice — Lattice cryptography library
• luxfi/standard — fhEVM smart contracts

Contributing

Contributions welcome! Please ensure tests pass before submitting PRs:

CGO_ENABLED=0 go test -v ./...
go vet ./...