《数量经济技术经济研究》编辑部

文章摘要

贾鹏飞.央行数字货币与个人隐私——兼论央行数字货币的经济影响[J].数量经济技术经济研究,2025,(6):132-150

央行数字货币与个人隐私——兼论央行数字货币的经济影响

Central Bank Digital Currency and Privacy: The Economic Impact of Central Bank Digital Currency

DOI：

英文关键词: Central Bank Digital Currency Privacy Cash Welfare Analysis New Monetarist Model

基金项目:

作者	单位
贾鹏飞	南京大学商学院

中文摘要:

随着数字经济蓬勃发展和私人加密货币广泛兴起,央行数字货币备受关注。本文基于隐私保护的视角,通过构建新货币主义模型研究央行数字货币的经济影响,研究发现个人隐私在经济环境中起到十分重要的作用,其可影响模型的产出及均衡水平。当隐私成本较小时,经济个体将选择使用央行数字货币。此时，央行数字货币的使用可以达到最优的产出水平并实现最优均衡。当隐私成本较大时,经济个体将选择使用现金,此时的产出水平低于最优。进一步分析发现,央行数字货币的利率也可影响产出和社会福利。增加该利率可以降低持有央行数字货币的金融成本并增加央行数字货币的净收益，进而增加产出和福利。本文认为,央行数字货币的引入可对经济社会产生正面影响,有助于达到最优产出并提升福利,但这一结论在很大程度上受个人隐私成本的影响。本文以个人隐私为着眼点拓展了对央行数字货币经济影响的理解,为央行数字货币的研发与应用提供了新的思路。

英文摘要:

With the rapid development of the digital economy and cryptocurrency, central bank digital currencies (CBDCs) have received a lot of attention. This study investigates the economic impact of CBDC and compares CBDC and cash through the lens of a New Monetarist model. As CBDC is account-based, it is not fully anonymous. Thus, holding CBDC incurs a privacy cost. However, CBDC has the benefit of bearing interest. Although cash can protect users’ privacy, it does not carry any interest. This study finds that privacy plays a crucial role in the economy, and the level of privacy cost affects output and welfare. We demonstrate that when privacy cost is relatively low, agents will use CBDC over cash. Moreover, the economy can achieve the first-best level of output and welfare. When privacy cost is relatively high, agents will choose to use cash, whereas the first-best level of economic outcome is not achieved. In addition, we find that the interest rate on CBDC can be used to improve welfare. In particular, raising the interest rate on CBDC can lower the marginal cost of holding CBDC, thereby increasing the net benefit of CBDC as well as output and welfare. Overall, this study reveals that introducing a CBDC can have positive effects on the economy. However, this result depends crucially on privacy cost. From the perspective of privacy protection, this study strengthens our understanding of the economic effects of CBDC and provides useful policy suggestions for the development of CBDC.The contributions of the study are as follows. First, this study investigates CBDC and privacy from the perspective of users’ privacy protection. Very few studies have focused on this topic. To model privacy, we assume that using CBDC can incur a fixed privacy cost. This assumption comes from the fact that CBDC, by design, is not fully anonymous. In addition, this study investigates the effects of privacy on economic output and welfare. We find that privacy can play an important role in the economy. In particular, when privacy cost is relatively low, agents will choose to hold CBDC, and using CBDC can achieve an efficient equilibrium. Second, this study examines a “cash-like” CBDC. The existing literature typically studies a “deposit-like” CBDC and focuses on whether the introduction of CBDC can lead to “financial disintermediation.” Unlike those studies, we examine a “cash-like” CBDC.This is because in China, CBDC is positioned as M0, and it is important for CBDC to be complementary and substitutable for cash. From the perspective of modelling, we need to compare cash and CBDC. In particular, we need to understand the potential benefits of physical cash, compared to CBDC. This study does this based on anonymity. Cash is anonymous, whereas CBDC is not. Further, there is a trade-off when agents use cash and CBDC. Third, this study investigates the welfare effects of CBDC and whether using CBDC can improve welfare. Studying this can provide a theoretical foundation for introducing CBDC. We find that using CBDC can increase output and welfare and can even achieve the first-best allocation. However, this result requires that privacy cost should be relatively low. Therefore, it is crucial to protect users’ privacy and reduce privacy cost.Based on the results, this study makes several policy suggestions. First, central banks should steadily advance the pilot and issuance of CBDC. We find that the introduction of CBDC can have positive effects on payment systems, economic output, and social welfare. However, there are several potential risks of CBDC that we do not discuss. Thus, central banks should implement CBDC but do so cautiously. Second, central banks should pay close attention to users’ privacy protection when designing CBDC. Our results depend crucially on privacy cost. When the privacy cost is relatively low, agents will use CBDC. However, when the privacy cost is relatively high, agents will use cash, and the first-best level of allocation cannot be achieved. Third, central banks should promote the use of CBDC in payment. This is because we find that introducing CBDC can reduce financial frictions and thus increase payment efficiency. However, cash also plays an important role in payment, and central banks should meet agents’ demand for cash.Fourth, central banks should explore the use of CBDC in implementing monetary policy. We find that the interest rate on CBDC can work as a monetary policy instrument and affect output and welfare. In particular, raising the CBDC interest rate can lower the financial cost associated with it, which would increase output and welfare.

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