- Add Prometheus metrics for marketplace API throughput and error rates with new dashboard panels - Implement confidential transaction models with encryption support and access control - Add key management system with registration, rotation, and audit logging - Create services and registry routers for service discovery and management - Integrate ZK proof generation for privacy-preserving receipts - Add metrics instru
5.2 KiB
5.2 KiB
ZK Technology Comparison for Receipt Attestation
Overview
Analysis of zero-knowledge proof systems for AITBC receipt attestation, focusing on practical considerations for integration with existing infrastructure.
Technology Options
1. zk-SNARKs (Zero-Knowledge Succinct Non-Interactive Argument of Knowledge)
Examples: Groth16, PLONK, Halo2
Pros:
- Small proof size: ~200 bytes for Groth16
- Fast verification: Constant time, ~3ms on-chain
- Mature ecosystem: circom, snarkjs, bellman, arkworks
- Low gas costs: ~200k gas for verification on Ethereum
- Industry adoption: Used by Aztec, Tornado Cash, Zcash
Cons:
- Trusted setup: Required for Groth16 (toxic waste problem)
- Longer proof generation: 10-30 seconds depending on circuit size
- Complex setup: Ceremony needs multiple participants
- Quantum vulnerability: Not post-quantum secure
2. zk-STARKs (Zero-Knowledge Scalable Transparent Argument of Knowledge)
Examples: STARKEx, Winterfell, gnark
Pros:
- No trusted setup: Transparent setup process
- Post-quantum secure: Resistant to quantum attacks
- Faster proving: Often faster than SNARKs for large circuits
- Transparent: No toxic waste, fully verifiable setup
Cons:
- Larger proofs: ~45KB for typical circuits
- Higher verification cost: ~500k-1M gas on-chain
- Newer ecosystem: Fewer tools and libraries
- Less adoption: Limited production deployments
Use Case Analysis
Receipt Attestation Requirements
- Proof Size: Important for on-chain storage costs
- Verification Speed: Critical for settlement latency
- Setup Complexity: Affects deployment timeline
- Ecosystem Maturity: Impacts development speed
- Privacy Needs: Moderate (hiding amounts, not full anonymity)
Quantitative Comparison
| Metric | Groth16 (SNARK) | PLONK (SNARK) | STARK |
|---|---|---|---|
| Proof Size | 200 bytes | 400-500 bytes | 45KB |
| Prover Time | 10-30s | 5-15s | 2-10s |
| Verifier Time | 3ms | 5ms | 50ms |
| Gas Cost | 200k | 300k | 800k |
| Trusted Setup | Yes | Universal | No |
| Library Support | Excellent | Good | Limited |
Recommendation
Phase 1: Groth16 for MVP
Rationale:
- Proven technology: Battle-tested in production
- Small proofs: Essential for cost-effective on-chain verification
- Fast verification: Critical for settlement performance
- Tool maturity: circom + snarkjs ecosystem
- Community knowledge: Extensive documentation and examples
Mitigations for trusted setup:
- Multi-party ceremony with >100 participants
- Public documentation of process
- Consider PLONK for Phase 2 if setup becomes bottleneck
Phase 2: Evaluate PLONK
Rationale:
- Universal trusted setup (one-time for all circuits)
- Slightly larger proofs but acceptable
- More flexible for circuit updates
- Growing ecosystem support
Phase 3: Consider STARKs
Rationale:
- If quantum resistance becomes priority
- If proof size optimizations improve
- If gas costs become less critical
Implementation Strategy
Circuit Complexity Analysis
Basic Receipt Circuit:
- Hash verification: ~50 constraints
- Signature verification: ~10,000 constraints
- Arithmetic operations: ~100 constraints
- Total: ~10,150 constraints
With Privacy Features:
- Range proofs: ~1,000 constraints
- Merkle proofs: ~1,000 constraints
- Additional checks: ~500 constraints
- Total: ~12,650 constraints
Performance Estimates
Groth16:
- Setup time: 2-5 hours
- Proving time: 5-15 seconds
- Verification: 3ms
- Proof size: 200 bytes
Infrastructure Impact:
- Coordinator: Additional 5-15s per receipt
- Settlement layer: Minimal impact (fast verification)
- Storage: Negligible increase
Security Considerations
Trusted Setup Risks
- Toxic Waste: If compromised, can forge proofs
- Setup Integrity: Requires honest participants
- Documentation: Must be publicly verifiable
Mitigation Strategies
-
Multi-party Ceremony:
- Minimum 100 participants
- Geographically distributed
- Public livestream
-
Circuit Audits:
- Formal verification where possible
- Third-party security review
- Public disclosure of circuits
-
Gradual Rollout:
- Start with low-value transactions
- Monitor for anomalies
- Emergency pause capability
Development Plan
Week 1-2: Environment Setup
- Install circom and snarkjs
- Create basic test circuit
- Benchmark proof generation
Week 3-4: Basic Circuit
- Implement receipt hash verification
- Add signature verification
- Test with sample receipts
Week 5-6: Integration
- Add to coordinator API
- Create verification contract
- Test settlement flow
Week 7-8: Trusted Setup
- Plan ceremony logistics
- Prepare ceremony software
- Execute multi-party setup
Week 9-10: Testing & Audit
- End-to-end testing
- Security review
- Performance optimization
Next Steps
- Immediate: Set up development environment
- Research: Deep dive into circom best practices
- Prototype: Build minimal viable circuit
- Evaluate: Performance with real receipt data
- Decide: Final technology choice based on testing