Offline e-HKD rCBDC Transactions

This paper explores the key properties, security concerns and potential solutions for retail Central Bank Digital Currency (rCBDC) offline transactions, with a focus on the e-Hong Kong Dollar (e-HKD) where relevant. The paper identifies six key properties of rCBDC offline transactions, including No Double Spending, Non-repudiation, Unforgeability, Privacy and Anonymity, Prevention of Man-In-the-Middle Attacks, and Prevention of DDoS Attacks, which are essential for ensuring the security, integrity, and usability of the rCBDC system. The paper discusses various cryptographic techniques and secure protocols that can be used to build a secure and trustworthy rCBDC system. The paper highlights the need for advanced technological solutions such as encryption, privacy-preserving techniques, and secure hardware improvements to protect against potential attacks. The paper concludes by emphasizing the importance of close collaboration between central banks, governments, private sector partnerships, and academia to develop a comprehensive and holistic approach to rCBDC integration and adoption.