Threshold FHE for Distributed Decryption

This references Lux's independent threshold implementation:

• ✅ Core implementation: lux/node/vms/kmsvm/ (Go)
• ✅ TFHE library: github.com/luxfi/tfhe (Go)
• ✅ Post-quantum: ML-KEM (FIPS 203) via github.com/luxfi/crypto
• ✅ NO code derived from Zama threshold or tfhe-rs
• ✅ Protected by Lux Industries patent portfolio

Threshold FHE enables N validators to hold shares of a decryption key, requiring t-of-N collaboration to decrypt. This provides:

• No single point of failure - No single party can decrypt
• Censorship resistance - Any t validators can participate
• Quantum safety - ML-KEM key distribution

Lux implements threshold FHE directly in the node software:

github.com/luxfi/node/vms/kmsvm/   <- Go KMS VM
github.com/luxfi/tfhe/             <- Go TFHE library
github.com/luxfi/crypto/mlkem/     <- Post-quantum KEM
github.com/luxfi/lattice/          <- Lattice primitives

Instead of separate threshold protocol rounds, Lux integrates decryption shares directly into consensus votes:

Traditional Approach:
  Consensus Round 1 → Block Finality
  Threshold Round 2 → Collect Shares
  Threshold Round 3 → Combine & Decrypt

Lux Approach:
  Single Round → Block Finality + Decryption
  (Shares piggybacked on consensus votes)

This reduces latency and leverages existing stake-weighted validator sampling.

Threshold operations are accessed via the K-Chain VM RPC:

import { LuxKMS } from '@luxfhe/kms';

const kms = new LuxKMS({ network: 'mainnet' });

// Generate threshold key (distributed to validators)
const { publicKey, keyId } = await kms.generateKey({
  threshold: 67,
  totalShares: 100,
});

// Request decryption (collects shares automatically)
const plaintext = await kms.decrypt(ciphertext, { keyId });

Based on threshold cryptography research:

• Shamir Secret Sharing (1979)
• Threshold signatures (multiple papers)
• Our own innovations (PAT-FHE-001 through PAT-FHE-009)

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]

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