Paper 2023/713 Original: eprint.iacr.org/2023/713 ↗

KAIME : Central Bank Digital Currency with Realistic and Modular Privacy

Abstract

Recently, with the increasing interest in Central Bank Digital Currency (CBDC), many countries have been working on researching and developing digital currency. The most important reasons for this interest are that CBDC eliminates the disadvantages of traditional currencies and provides a safer, faster, and more efficient payment system. These benefits also come with challenges, such as safeguarding individuals’ privacy and ensuring regulatory mechanisms. While most researches address the privacy conflict between users and regulatory agencies, they miss an important detail. Important parts of a financial system are banks and financial institutions. Some studies ignore the need for privacy and include these institutions in the CBDC system, no system currently offers a solution to the privacy conflict between banks, financial institutions, and users. In this study, while we offer a solution to the privacy conflict between the user and the regulatory agencies, we also provide a solution to the privacy conflict between the user and the banks. Our solution, KAIME has also a modular structure. The privacy of the sender and receiver can be hidden if desired. Compared to previous related research, security analysis and implementation of KAIME is substantially simpler because simple and well-known cryptographic methods are used.