Paper 2022/1443

DOT-M: A Dual Offline Transaction Scheme of Central Bank Digital Currency for Trusted Mobile Devices

Bo Yang, National Fintech Evaluation Center
Yanchao Zhang, National Fintech Evaluation Center
Dong Tong, National Fintech Evaluation Center
Abstract

In recent years, many major economies have paid close attention to central bank digital currency (CBDC). As an optional attribute of CBDC, dual offline transaction is considered to have great practical value under the circumstances for payment without network connection. However, there is no public report or paper on how to securely design or implement the dual offline transaction function specifically for CBDC. In this paper, we propose DOT-M, a practical dual offline transaction scheme designed for the mobile device user as either a payer or a payee. Precisely, adopting secure element (SE) and trusted execution environment (TEE), the architecture of trusted mobile device is constructed to protect security-sensitive keys and execution of the transaction protocol. According to the trusted architecture, the data structure for offline transaction is designed as well. On this basis, we describe the core procedures of DOT-M in detail, including registration, account synchronization, dual offline transaction, and online data updating. We also enumerate the exceptional situations that may occur during the dual offline transaction, and give specific handling methods for each situation. Moreover, six security properties of the scheme are analyzed under realistic assumptions. A prototype system is implemented and finally tested with possible parameters. The security analysis and experimental results indicate that our scheme could meet the practical requirement of CBDC offline transaction for mobile users from both aspects of security and efficiency.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint.
Keywords
Central Bank Digital Currency (CBDC)Dual Offline TransactionSecure Element (SE)Trusted Execution Environment (TEE)
Contact author(s)
bobobrave @ qq com
zhangyanchao @ bctest com
tongdong @ bctest com
History
2023-01-03: revised
2022-10-22: received
See all versions
Short URL
https://ia.cr/2022/1443
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2022/1443,
      author = {Bo Yang and Yanchao Zhang and Dong Tong},
      title = {DOT-M: A Dual Offline Transaction Scheme of Central Bank Digital Currency for Trusted Mobile Devices},
      howpublished = {Cryptology ePrint Archive, Paper 2022/1443},
      year = {2022},
      note = {\url{https://eprint.iacr.org/2022/1443}},
      url = {https://eprint.iacr.org/2022/1443}
}
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