LuxFHE VM

Confidential Smart Contract Execution Environment

---

⚠️ Important IP Notice

This is Lux's independent fhEVM implementation:

• ✅ Built on github.com/luxfi/tfhe (our Go TFHE library)
• ✅ Uses lux/evm/precompile/contracts/fhe/ (our precompiles)
• ✅ Threshold decryption via lux/node/vms/kmsvm/ (our KMS VM)
• ✅ NO code derived from Zama fhevm, tfhe-rs, or any third-party FHE library
• ✅ Protected by Lux Industries patent portfolio (9 FHE patents pending)

---

Overview

LuxFHE VM enables fully confidential smart contracts on Lux Network. Contracts can operate on encrypted data without ever decrypting it, enabling:

• Private DeFi: Hidden balances, amounts, and transactions
• Confidential Voting: Secret ballots with verifiable tallies
• Private Identity: Zero-knowledge credential verification
• Encrypted AI: Inference on encrypted data

Architecture

┌─────────────────────────────────────────────────────────────────┐
│                      LuxFHE VM Architecture                      │
├─────────────────────────────────────────────────────────────────┤
│  Application Layer                                               │
│    ├── @luxfhe/sdk          - JavaScript/TypeScript SDK          │
│    ├── @luxfhe/solidity     - Solidity contract library          │
│    └── @luxfhe/hardhat      - Development plugin                 │
├─────────────────────────────────────────────────────────────────┤
│  Smart Contract Layer                                            │
│    ├── FHE.sol              - High-level encrypted types         │
│    ├── FheOS.sol            - Precompile interface               │
│    └── Tokens, Governance   - Ready-to-use contracts             │
├─────────────────────────────────────────────────────────────────┤
│  Precompile Layer (lux/evm/precompile/contracts/fhe/)           │
│    ├── FheAdd (0x0080)      - Encrypted addition                 │
│    ├── FheMul (0x0082)      - Encrypted multiplication           │
│    ├── FheDecrypt (0x00A0)  - Threshold decryption request       │
│    └── ...                  - Full FHE operation set             │
├─────────────────────────────────────────────────────────────────┤
│  Crypto Layer (github.com/luxfi/tfhe)                           │
│    ├── Encryptor            - Public key encryption              │
│    ├── Evaluator            - Homomorphic operations             │
│    ├── Decryptor            - Secret key decryption              │
│    └── Built on github.com/luxfi/lattice                        │
├─────────────────────────────────────────────────────────────────┤
│  Key Management (lux/node/vms/kmsvm/)                           │
│    ├── Threshold Sharing    - N-of-M key distribution            │
│    ├── ML-KEM               - Post-quantum key encapsulation     │
│    └── Consensus Integration- Decryption via validator votes     │
└─────────────────────────────────────────────────────────────────┘

Key Features

1. Native EVM Integration

FHE operations are available as precompiles, callable from any Solidity contract:

import "@luxfhe/solidity/FHE.sol";

contract ConfidentialTransfer {
    mapping(address => euint256) private balances;
    
    function transfer(address to, inEuint256 calldata encAmount) public {
        euint256 amount = FHE.asEuint256(encAmount);
        
        // All operations on encrypted data
        ebool hasBalance = FHE.ge(balances[msg.sender], amount);
        balances[msg.sender] = FHE.select(
            hasBalance,
            FHE.sub(balances[msg.sender], amount),
            balances[msg.sender]
        );
        balances[to] = FHE.add(balances[to], amount);
    }
}

2. Threshold Decryption

Decryption requires consensus among validators:

// Request decryption (async)
uint256 requestId = FHE.requestDecrypt(encryptedValue);

// Callback receives plaintext after threshold met
function onDecryptionResult(uint256 requestId, uint256 value) external {
    // Process decrypted value
}

3. Permit System

Users control access to their encrypted data:

// Generate permit (signs EIP-712 message)
const permit = await fhe.generatePermit(contractAddress);

// Contract can now decrypt user's data
const balance = await fhe.decrypt.uint256(encBalance, permit);

Supported Operations

Category	Operations
Arithmetic	add, sub, mul, div, rem, neg
Comparison	eq, ne, lt, le, gt, ge, min, max
Bitwise	and, or, xor, not, shl, shr, rotl, rotr
Control	select (encrypted ternary)
Random	randBool, randUint8, randUint32, ...
Decrypt	requestDecrypt (threshold)

Performance

Operation	Gas Cost	Latency
FHE Add	50,000	~5ms
FHE Mul	150,000	~15ms
FHE Compare	30,000	~3ms
FHE Decrypt	500,000	~500ms (threshold)

Development

Local Setup

# Start local Lux network with FHE
lux network start --fhe

# Deploy FHE contract
npx hardhat run scripts/deploy.ts --network local

# Run tests
npx hardhat test

Hardhat Configuration

// hardhat.config.ts
import "@luxfhe/hardhat";

export default {
  solidity: "0.8.24",
  networks: {
    luxTestnet: {
      url: "https://api.testnet.lux.network",
      chainId: 8888,
      fhe: true, // Enable FHE support
    },
  },
};

Academic Foundation

Built on peer-reviewed research:

1. Chillotti et al. (2020) - TFHE scheme
2. Ducas & Micciancio (2015) - FHEW bootstrapping
3. Original innovations protected by 9 patent applications

License

Lux Research License with Patent Reservation

• ✅ Free for research and academic use
• ✅ Free on Lux Network (mainnet/testnet)
• 📧 Commercial license required for other networks

Contact: [email protected]

Related Repositories

Repository	Description
luxfi/tfhe	Go TFHE library
luxfi/lattice	Lattice cryptography
luxfi/standard	Smart contracts
luxfi/node	Lux node with FHE precompiles

---

© 2020-2025 Lux Industries Inc. All rights reserved.