线下支付的稳健风险框架

Federal Reserve Board, Washington, D.C.ISSN 1936-2854 (Print) A Robust Risk Framework for Offline Payments Bikash Poudel, Sarah Carey, Robert Flynn, Chakrapani Narayan, RichardPayne, Eshwar Satrasala, Seaira Spooney, and James Lovejoy 2025-105 Please cite this paper as:Poudel, Bikash, Sarah Carey, Robert Flynn, Chakrapani Narayan, Richard Payne, EshwarSatrasala, Seaira Spooney, and James Lovejoy (2025).“A Robust Risk Framework forOffline Payments,” Finance and Economics Discussion Series 2025-105. Washington: Board NOTE: Staff working papers in the Finance and Economics Discussion Series (FEDS) are preliminarymaterials circulated to stimulate discussion and critical comment.The analysis and conclusions set forthare those of the authors and do not indicate concurrence by other members of the research staff or the A Robust Risk Framework for Offline Payments Bikash Poudel, Sarah Carey, Robert Flynn, Chakrapani Narayan, Richard Payne, Eshwar Satrasala,Seaira Spooney, and James Lovejoy1 Abstract The capability to make offline digital payments is emerging as a vital component of the broaderpayments ecosystem, especially in scenarios in whichinternet connectivity is unavailable suchas during a crisis or natural disaster. Offline digital payment services offer a secure and reliablealternative to cash. Even so, there are a limited number of viable offline payment protocols inproduction today. Our work introduces a comprehensive model for a secure, end-to-end offline Introduction Offline payment functionality is an emerging digital payment technology that enables users totransact without an internet connection. Currently, physical cash is the standard offline paymentsolution. However, in times of crisis, reliable access to cash presents operational and logisticalchallenges for central banks, depository institutions, and consumers alike. By not relying oninternet access, offline payment functionality can replicate some features of cash (e.g.,can beusedwithout a connection) while minimizing its downsides, such as theneed for physical Currently, there is a lack of an end-to-endoffline digital payments systems in production2. Ourwork addresses the offline payments challenges of double-spending and counterfeiting byproposing an end-to-end offline model that couldensure the secure exchange of an offline Beyond the general benefits to the broader ecosystem, offline payments could offer significantadvantages to merchants and consumers. Presently, consumers lack a digital alternative to cashthat functions without internet access. U.S. payments system operators are also limited in theirability to continue operating payments systems without internet connectivity. Therefore, Background Presently, offline payments areprimarilyfacilitated using physical cash.Although consumers areincreasingly adopting mobile payment methods, consumers have expressed a clear desire to usecash in times of crisis (Judson 2024) or when there is a prolonged loss of internet connectivity.Current trends show that the growth in mobile payments usage is outpacing the decline in cash-based payments.For example, according to the Atlanta Fed’s 2024 Survey and Diary ofConsumer Payment Choice,3while the use of cash declined by 2 percentage points, from 16 OfflineData Transfer Technology Offline paymentscouldutilize either near field communication(NFC)or Bluetooth technology asdata transport methods to securely exchange tokens from one phone to another over anencrypted channel.In our model, to executea transaction, the user would bring twosmartphones into close proximity to initiate the data transfer. The two wallets would then Benefits ofOfflinePayments Offline payment technologies offer several benefits to consumers due to their privacy,accessibility, security, and safety features: 1.Privacy:Offline payments are cash-like, ensuring transaction privacywithin the digitalwallet. For example, in our model, digital wallets do not contain any personally identifiableinformation (PII), only wallet addresses and proofs.2.Accessibility:Payments can be made with a smartphone or at a point-of-sale terminalwithout the need for internet connectivity, Our Proposed Solution Our solution introduces an offline token transfermodel, leveraging our novel SignOncesemantics-based cryptographic protocol implemented in a tamper-resistant secure element (SE)hardware chip.4The SE, integrated within a smartphone's system-on-chip, executes critical token transfer protocol. We implemented the offline protocol in a digital wallet and tested theoffline token transfer protocol in iOS smartphones using Bluetooth as the transport method. For Our protocol is also distinct in that it is operating system-agnostic and addresses the challengesof double-spending and counterfeiting, even when the wallet remains offline for a prolongedperiod. Our work ensures that the offline wallet can verify the authenticity of a received token SolutionScope We focused our work on device-to