Automatic Teller Machines for Offline E-cash

Computer Science > Cryptography and Security [Submitted on 11 Apr 2026] Automatic Teller Machines for Offline E-cash Anrin Chakraborti, Qingzhao Zhang, Jingjia Peng, Morley Mao, Michael K. Reiter Electronic cash (e-cash) is a digital alternative to physical currency that allows anonymous transactions between users and merchants. Typically, coins in an e-cash scheme are only dispensed through a central bank. A drawback of this approach is that the bank is always on the critical path during withdrawals, and if a reliable connection to the bank is temporarily unavailable, users may be unable to withdraw coins in a timely fashion. As with physical currency, there are benefits to supporting a decentralized infrastructure where withdrawals can be performed without involving the bank in the critical path. We propose the design of a new cryptographic bearer token that can be dispensed by automatic teller machines (ATM) in a fully offline e-cash scheme. Such bearer tokens provide anonymity, unforgeability and untraceability, i.e., users cannot be tracked by their spending activities or the locations of withdrawal. We formalize the requirements of an e-cash scheme with multiple issuers and propose an efficient design building on top of the compact e-cash protocol of Camenisch et al. (EUROCRYPT 2005). Our construction leverages an unforgeable and doubly-anonymous voucher that allows a one-time transfer of coins between an ATM and a user, while hiding their identities from parties not involved in the transaction. Subjects: Cryptography and Security (cs.CR) Cite as: arXiv:2604.10380 [cs.CR]   (or arXiv:2604.10380v1 [cs.CR] for this version)   https://doi.org/10.48550/arXiv.2604.10380 Focus to learn more Submission history From: Anrin Chakraborti [view email] [v1] Sat, 11 Apr 2026 23:30:13 UTC (301 KB) Access Paper: HTML (experimental) view license Current browse context: cs.CR < prev   |   next > new | recent | 2026-04 Change to browse by: cs References & Citations NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)