LPsLux Proposals
Network
LP-2

Recursive Network Architecture and Cross-Chain Interoperability

Final

Introduces Lux's recursive network architecture, wherein the network consists of multiple parallel chains that can each host specialized applications while remaining interconnected through native cross-chain messaging.

Category
Core
Created
2025-01-26

LP-134 canonical naming (2025-12-15): This LP predates the M-Chain / F-Chain split. Per LP-134 (Lux Chain Topology), MPC ceremonies for bridge custody of external wallets (BTC, ETH, SOL, etc.) now run on M-Chain (CGGMP21, FROST, Pulsar-general). FHE compute and TFHE bootstrap-key generation run on F-Chain. The name "T-Chain" is removed entirely — teleport / cross-chain messaging is B-Chain (bridgevm, LP-6000). Where this LP says "T-Chain MPC" / "T-Chain threshold" / "T-Chain FHE" / "T-Chain custody", read it as M-Chain (for MPC) or F-Chain (for FHE).

Normative topology + fee model: LP-0130. The chain-hierarchy diagram in this LP is a taxonomic view; LP-0130 is the normative roster (10 chains, P/X as UTXO rails, all others funding fee balances from X via ImportTx/ExportTx). Where this LP frames chains as "primary" vs "optional L1", LP-0130 supersedes with a single flat roster + fee-policy matrix.

LP-0002: Recursive Network Architecture and Cross-Chain Interoperability

Abstract

Lux Network employs a recursive network architecture where multiple specialized chains operate in parallel, each optimized for specific workloads while sharing common infrastructure for security and interoperability. This document specifies how chains are created, how they coordinate, and how cross-chain messaging enables seamless asset and data transfers.

Motivation

Single-chain architectures face fundamental scalability limits. Rather than forcing all applications to compete for the same block space, Lux enables purpose-built chains that can:

  • Optimize for workload: Different consensus parameters, VMs, and gas policies per chain
  • Isolate state: Application-specific chains don't bloat shared state
  • Scale horizontally: Add chains as demand grows
  • Customize rules: Compliance, access control, and economic models per chain

Specification

Chain Hierarchy

Lux organizes chains into a recursive structure:

┌─────────────────────────────────────────────────────────────────────┐
                         LUX NETWORK                                 
├─────────────────────────────────────────────────────────────────────┤
  PRIMARY NETWORK (Required  every validator)                       
    P-Chain: Platform  Validator coordination, staking, chain mgmt  
    Q-Chain: Quantum   Post-quantum consensus finality (BLS+PQ)     
├─────────────────────────────────────────────────────────────────────┤
  OPTIONAL L1 CHAINS (Validator opt-in via --track-chains)           
    C-Chain: Contract     General-purpose EVM                       
    X-Chain: Exchange     High-throughput asset transfers (DAG)      
    D-Chain: DEX          Native CLOB + AMM orderbook               
    Z-Chain: ZK           Zero-knowledge proof verification         
    M-Chain: MPC          CGGMP21/FROST/Pulsar threshold signing    
    F-Chain: FHE          Encrypted EVM + threshold-FHE decryption  
    B-Chain: Bridge       Cross-network asset movement              
    A-Chain: Attestation  AI verification, proof-of-inference       
├─────────────────────────────────────────────────────────────────────┤
  L2 CHAINS (Sovereign chain networks  own validators)              
    Require P+Q only. Q optional for non-quantum L1s.                
    Example: a regulated securities L1 (EVM + DEX + FHE)             
├─────────────────────────────────────────────────────────────────────┤
  L1 CHAINS (Independent networks  own consensus)                   
    Q optional for quantum safety on native consensus.               
└─────────────────────────────────────────────────────────────────────┘

See LP-0110 for the full P+Q consensus specification.

Chain Registration

New chains register with the P-Chain, which maintains:

  • Validator sets per chain
  • Chain metadata and configuration
  • Cross-chain messaging registry
  • Staking requirements

Recursive Properties

The architecture is recursive because:

  1. Chains can spawn chains: Application chains can deploy their own sub-chains
  2. Validators can validate multiple chains: Same validator set can secure multiple chains
  3. Messaging propagates recursively: Cross-chain messages route through the hierarchy
  4. Security inherits: Child chains inherit security guarantees from parent validators

Cross-Chain Messaging

Warp Protocol

Lux implements native cross-chain messaging via the Warp protocol:

Chain A                    P-Chain                    Chain B
   │                          │                          │
   │  1. Create message       │                          │
   │──────────────────────────>                          │
   │                          │                          │
   │  2. Validators sign      │                          │
   │  (BLS aggregation)       │                          │
   │                          │                          │
   │                          │  3. Message relayed      │
   │                          │─────────────────────────>│
   │                          │                          │
   │                          │  4. Verify signature     │
   │                          │  against validator set   │
   │                          │                          │

Key Properties:

  • No external bridges or relayers required
  • BLS multi-signatures for efficient verification
  • Validator set from source chain is trusted authority
  • Supermajority (67%+) required for message validity

Message Format

type WarpMessage struct {
    SourceChainID  ids.ID
    Payload        []byte
    SourceAddress  common.Address
    Nonce          uint64
    Signature      []byte  // Aggregated BLS
}

Rationale

Why Recursive Architecture?

vs. Single Chain: Horizontal scaling without state bloat vs. Sharding: Simpler coordination, chains are independent vs. L2 Rollups: Native security, no data availability concerns vs. External Bridges: Trustless, protocol-native messaging

Why BLS Signatures?

BLS allows signature aggregation: n validators produce one constant-size signature. This enables efficient cross-chain verification without transmitting n individual signatures.


Backwards Compatibility

This architecture is foundational. All Lux chains follow this model.

New chains must:

  1. Register with P-Chain
  2. Publish validator set
  3. Implement Warp message handling

Security Considerations

Chain Isolation

Chains are isolated by default. A compromised chain cannot:

  • Affect other chains' state
  • Forge messages from other chains
  • Access other chains' assets without proper messaging

Validator Security

Cross-chain security depends on validator honesty:

  • Source chain validators must not forge messages
  • 33%+ Byzantine tolerance (67% supermajority required)
  • Slashing for provably malicious behavior

Message Verification

Receiving chains MUST:

  • Verify signature against known validator set
  • Check nonce for replay prevention
  • Validate source chain ID

Implementation

Chain Manager

Location: ~/work/lux/node/chains/

Key Files:

  • manager.go - Chain lifecycle management
  • registrant.go - Chain creation hooks
  • nets.go - Network isolation and chain namespace

Warp Messaging

Location: ~/work/lux/node/vms/platformvm/warp/

Features:

  • BLS signature aggregation across validators
  • Message validation and verification
  • Chain-to-chain trusted messaging

Test Cases

cd ~/work/lux/node/chains && go test -v ./...
cd ~/work/lux/node/vms/platformvm/warp && go test -v ./...

  • LP-0: Network Architecture Overview
  • LP-3600: Virtual Machine and Execution Environment
  • LP-605: Validator Management

Copyright and related rights waived via CC0.