布鲁金斯学会-中央银行数字货币的设计选择：政策和技术注意事项（英文）-2020.7-110页_940kb

Design Choices for Central Bank Digital Currency: Policy and Technical Considerations Summary

Core Content

This paper explores the technical and policy design choices for Central Bank Digital Currencies (CBDCs), emphasizing the complexity of implementing such systems. It outlines the potential benefits and risks associated with CBDCs and presents a comprehensive analysis of the technical, financial, and legal considerations involved in their development and deployment.

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Main Benefits of CBDC

• Efficiency: CBDC can reduce transaction friction, lower monetary costs, and increase speed while ensuring finality.
• Broader Tax Base: By making transactions traceable, CBDC can help bring more economic activity into the tax net, reduce tax evasion, and improve tax revenues.
• Flexible Monetary Policy: CBDC allows for the possibility of negative nominal interest rates and non-distortionary helicopter drops, offering new tools for central banks.
• Payment Backstop: CBDC could serve as a backup for private payment systems during crises, ensuring payment continuity.
• Financial Inclusion: Provides access to digital payment systems for the unbanked and underbanked, especially through mobile-based solutions.
• Opportunities for Novel Financial Technology: Enables the use of smart contracts and non-fungible tokens to create innovative financial instruments.

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Key Risks of CBDC

• Disintermediation of the Banking System: CBDC could reduce the role of commercial banks, potentially limiting innovation and increasing systemic risk.
• Miscalibration of Government Involvement: Overcentralization or undercentralization may lead to inefficiencies or regulatory gaps.
• Financial Risks Due to Lack of Regulatory Expertise: New technologies and rapid innovation may outpace regulatory frameworks, increasing risks.
• Loss of Privacy: CBDC systems may expose sensitive user data, requiring legal and technical mitigations to protect privacy.
• Technological Vulnerabilities: Even with conservative design, CBDCs are susceptible to security breaches and design flaws.

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Technical Considerations

Ledger Infrastructure

• CBDC relies on digital ledgers to record transactions and maintain account balances.
• The C-I-A triad (Confidentiality, Integrity, Availability) is crucial for ensuring secure and reliable operations.
• Centralized, semi-centralized, and decentralized ledger models are evaluated based on security, scalability, and flexibility.
• Scalability is a major challenge, as CBDC must support massive user onboarding and transaction volumes.

Account and Identity Management

• Account verification is essential to ensure that only authorized users can access CBDC accounts.
• Digital identity must be securely translated from real-world identities, and user authentication mechanisms are critical for system integrity.

Digital Wallets

• Digital wallets serve as user interfaces and authentication endpoints for CBDC.
• They allow users to initiate transactions, view balances, and interact with the CBDC system.
• Wallets can also facilitate transaction authentication to ensure the validity of submitted transactions.

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Privacy and Transparency

• CBDC must balance privacy and transparency, as it can be used for data mining by policymakers and law enforcement.
• Pseudonymous accounts are widely used but have privacy limitations.
• Techniques such as zero-knowledge proofs and advanced cryptography are proposed to enhance privacy.
• Regulatory compliance requires careful handling of transaction data and user information.

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Smart Contracts

• Smart contracts can expand the capabilities of CBDC systems by enabling automated financial instruments.
• They allow for novel applications such as conditional spending and dynamic monetary policy implementation.
• However, they also introduce complexity and potential risks, including security vulnerabilities and regulatory challenges.

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Secure Hardware

• Secure hardware, such as TPMs (Trusted Platform Modules), can enhance security architecture.
• It provides encryption and authentication capabilities but has limitations and vulnerabilities.
• The paper recommends careful integration of secure hardware into CBDC systems, depending on the security needs and design requirements.

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Legal Considerations

• Legal frameworks must address jurisdiction, compliance, privacy, fraud, and liens.
• Regulatory requirements for AML/CFT and taxation are significant considerations.
• The legal status of CBDC and its implications for financial oversight and user rights must be clearly defined.

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CBDC Models and Examples

• CBDCs can be retail (for individual users) or wholesale (for financial institutions).
• Libra (now Diem) and the digital yuan are discussed as examples of real-world CBDC initiatives.
• The digital yuan is highlighted for its patent filings that suggest advanced features and innovative use cases.

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Paper Roadmap

• The paper is structured to first introduce CBDC, then explore technical design choices, legal implications, and financial opportunities.
• It emphasizes the need for a modular and secure architecture that supports privacy, scalability, and flexibility.
• A vision for the future of CBDC is presented, highlighting the potential for innovation and regulatory oversight.

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Conclusion

CBDCs represent a significant shift in the way central banks interact with the financial system. While they offer numerous benefits, they also pose complex challenges in terms of security, privacy, scalability, and legal compliance. The paper concludes that careful design and policy considerations are essential for the successful deployment of CBDCs, and that collaboration between technologists, economists, and legal experts will be key to realizing their full potential.