2023-12-15-国际清算银行-Project_Tourbillon_探索CBDC的隐私_安全性和可扩展性_43页_2mb

Project Tourbillon Summary

Project Tourbillon explored the feasibility of implementing central bank digital currency (CBDC) features that address privacy, security, and scalability. The report focused on developing two distinct prototypes, eCash 1.0 (EC1) and eCash 2.0 (EC2), based on Chaum's eCash design.

Privacy was achieved through payer anonymity, ensuring consumers are anonymous to merchants, banks, and the central bank, while still allowing the central bank to monitor CBDC circulation at an aggregate level. EC1 provided unconditional privacy but had vulnerabilities to counterfeiting, while EC2 offered stronger security through an unspent coins list but required complex mix networks, potentially compromising privacy.

Security emphasized quantum-safe cryptography, implemented to resist future quantum computer threats. However, quantum-safe blind signature schemes faced challenges, including slower performance and reduced functionality, with throughput decreasing by a factor of 200 compared to classic RSA cryptography. This highlighted the need for further research.

Scalability was evaluated using payment data from Swiss transactions, demonstrating that both prototypes handled high transaction volumes with RSA cryptography, achieving over 2,200 transactions per second and near-instant response times. But quantum-safe versions showed significant performance drops.

The project concluded that while CBDCs with payer anonymity and strong security are feasible, trade-offs exist between features. Future work includes improving quantum-safe cryptography, extending use cases, and developing sustainable business models to address viability.