Quantum VM (Q-Chain)

The Quantum VM (Q-Chain) is a post-quantum resistant blockchain virtual machine. It provides quantum-safe signatures using Ringtail keys, parallel transaction processing, and bridges classical BLS consensus with post-quantum Ringtail threshold signatures via the Quasar consensus protocol. The Q-Chain uses DAG-based consensus for high-throughput parallel processing.

Architecture

• Ringtail Keys: Post-quantum key pairs (default 1024 bytes) with version tracking
• Quantum Signatures: SHA-512 based hashing with quantum noise and time-windowed validation
• Parallel Processing: Configurable batch sizes with worker pool architecture
• Quasar Bridge: Hybrid consensus connecting P-Chain BLS with Q-Chain Ringtail threshold signatures
• Quantum Stamps: Time-based stamps on blocks for replay attack prevention

Configuration

{
  "txFee": 1000,
  "createAssetTxFee": 10000,
  "quantumVerificationFee": 500,
  "maxParallelTxs": 100,
  "quantumAlgorithmVersion": 1,
  "ringtailKeySize": 1024,
  "quantumStampEnabled": true,
  "quantumStampWindow": "30s",
  "parallelBatchSize": 10,
  "quantumSigCacheSize": 10000,
  "ringtailEnabled": true,
  "minQuantumConfirmations": 1
}

Key Parameters

RPC API

The Q-Chain API uses the qvm namespace. Endpoint:

https://api.lux.network/{network}/ext/bc/{blockchain-id}/rpc

Block Operations

• qvm.getBlock -- Retrieve a block by ID (includes quantum signature status)

Quantum Key Operations

• qvm.generateRingtailKey -- Generate a new Ringtail key pair (returns public key, version, size)
• qvm.signWithQuantum -- Sign a message with a quantum-resistant signature
• qvm.verifyQuantumSignature -- Verify a quantum signature

Transaction Operations

• qvm.getPendingTransactions -- Get pending transactions in the mempool

Status

• qvm.getHealth -- Get VM health status
• qvm.getConfig -- Get current configuration

Example: Generate a Ringtail Key

curl -X POST --data '{
  "jsonrpc": "2.0",
  "method": "qvm.generateRingtailKey",
  "params": {},
  "id": 1
}' -H "Content-Type: application/json" \
  https://api.lux.network/mainnet/ext/bc/{blockchain-id}/rpc

Response:

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "publicKey": "a5f72c3d...",
    "version": 1,
    "keySize": 1024
  }
}

Hybrid Post-Quantum Security

The Q-Chain supports hybrid post-quantum cryptography combining classical algorithms with NIST-standardized primitives:

Ephemeral keys are generated per session and destroyed after handshake for forward secrecy. The system falls back gracefully to classical-only if the peer does not support PQ.

Related LPs

See lps.lux.network for the relevant Lux Proposals governing this chain.