Introduction
The Federal Reserve's exploration into Central Bank Digital Currency (CBDC) has reached significant milestones through initiatives like the "Project Hamilton." This collaborative effort between the Boston Federal Reserve and MIT’s Digital Currency Initiative (DCI) aims to develop a high-performance, resilient, and privacy-focused CBDC transaction processing system.
Key Objectives of Project Hamilton Phase 1
Performance Metrics:
- Process 99% of transactions within 5 seconds, matching the speed of U.S. card payments and instant interbank systems.
- Handle a minimum of 100,000 transactions per second, scalable to future demand.
System Resilience:
- Ensure uninterrupted service and data integrity even during multi-data-center failures.
Privacy Protection:
- Minimize data retention by design, reducing transactional footprints.
Design of the Fed’s Digital Currency Prototype
Core Components
- Currency Model: Unspent Transaction Output (UTXO) framework, similar to Bitcoin.
Participants:
- Transaction Processor: Validates and executes transactions.
- Issuer: Mints/redeems CBDC (via UTXO adjustments).
- User: Transfers funds via digital wallets (public/private key pairs).
UTXO Structure
Each unspent output is defined as:
UTXO := (value, public_key, serial_number) - Serial numbers ensure global uniqueness to prevent double-spending.
Validation & Efficiency Optimizations
Separate Validation Layers:
- Local Verification: Checks transaction format, signatures, and balance (via "Sentinels").
- Existence Validation: Confirms UTXO availability via a hashed Unspent Funds Hash Set (UHS), replacing raw UTXO storage for privacy and performance.
UHS Swaps:
- Input UTXOs are deleted from the UHS; outputs are added atomically.
High-Performance Architectures
Project Hamilton tested two models:
| Architecture | Throughput | Latency (99%) | Scalability |
|--------------------|---------------------|---------------|----------------------|
| Atomizer | ~170K TPS | <2 seconds | Limited by centralization |
| 2PC | ~1.7M TPS | <1 second | Horizontally scalable |
- 2PC outperforms by parallelizing non-conflicting transactions.
👉 Explore how OpenCBDC leverages these architectures
Comparative Analysis
vs. E-Cash (David Chaum)
- Similarities: Both use unique serialization for anti-counterfeiting.
- Advancements: Project Hamilton’s UHS reduces database bloat via hashing and sharding.
vs. Bitcoin
Shared UTXO model, but:
- No blockchain: Centralized UHS registry replaces distributed ledgers.
- Trust Model: Relies on institutional credibility vs. decentralized PoW.
vs. China’s Digital Yuan Prototype
- Commonalities: Centralized transaction登记 (registration centers).
- Divergence: Project Hamilton excludes intermediary roles and emphasizes hashed privacy.
Key Takeaways
- Technical Inclusivity: Blends crypto strengths (UTXO, hashing) with distributed systems’ scalability.
- Open Collaboration: OpenCBDC’s开源 fosters global R&D synergy.
FAQs
Q: How does Project Hamilton ensure transaction privacy?
A: By storing only hashed UTXOs (UHS) and minimizing data retention.
Q: Can the system handle offline payments?
A: Not yet—future phases will address offline functionality.
Q: What’s the role of intermediaries in this model?
A: Phase 1 omits intermediaries; later stages may integrate them for compliance.
👉 Learn more about CBDC innovations
Author: Yao Qian (Chairman of the CSRC’s Technology Supervision Bureau)