{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T17:58:35Z","timestamp":1775066315969,"version":"3.50.1"},"reference-count":38,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,25]],"date-time":"2023-01-25T00:00:00Z","timestamp":1674604800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Payment apps and digital wallets are powerful tools used to exchange e-money via the internet. However, with the progressive disappearance of cash, there is a need for the digital equivalent of physical banknotes to guarantee the same level of anonymity of private payments. Few efforts to solve the double-spending problem exist in P2P payments (i.e., in avoiding the possibility of a payer retaining copies of digital coins in absence of a trusted third party (TTP)), and further research efforts are needed to explore options to preserve the privacy of payments, as per the mandates of numerous central bank digital currency (CBDC) exploratory initiatives, such as the digital euro. Moreover, generic programmability requirements and energetic impacts should be considered. In this paper, we present a sustainable offline P2P payment scheme to face the double-spending problem by means of a one-time program (OTP) approach. The approach consists of wiping the business logic out of a client\u2019s app and allowing financial intermediaries to inject a certified payment code into the user\u2019s device, which will execute (asynchronously and offline) at the time of payment. To do so, we wrap each coin in a program at the time of withdrawal. Then the program exploits the trusted execution environment (TEE) of modern smartphones to transfer itself from the payer to the payee via a direct IoT link. To confirm the validity of the approach, we performed qualitative and quantitative evaluations, specifically focusing on the energetic sustainability of the proposed scheme. Results show that our payment scheme is energetically sustainable as the current absorbed for sending one coin is, at most, ~1.8 mAh on an Apple smartphone. We advance the state-of-the-art because the scheme meets the programmability, anonymity, and sustainability requirements (at the same time).<\/jats:p>","DOI":"10.3390\/s23031336","type":"journal-article","created":{"date-parts":[[2023,1,25]],"date-time":"2023-01-25T04:22:16Z","timestamp":1674620536000},"page":"1336","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":24,"title":["A Sustainable Approach to Delivering Programmable Peer-to-Peer Offline Payments"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9387-9277","authenticated-orcid":false,"given":"Luca","family":"Mainetti","sequence":"first","affiliation":[{"name":"Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2577-5972","authenticated-orcid":false,"given":"Matteo","family":"Aprile","sequence":"additional","affiliation":[{"name":"Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9297-1434","authenticated-orcid":false,"given":"Emanuele","family":"Mele","sequence":"additional","affiliation":[{"name":"Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3560-806X","authenticated-orcid":false,"given":"Roberto","family":"Vergallo","sequence":"additional","affiliation":[{"name":"Department of Innovation Engineering, University of Salento, 73100 Lecce, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,25]]},"reference":[{"key":"ref_1","unstructured":"Nakamoto, S. (2008). Decentralized Business Review, Available online: https:\/\/bitcoin.org\/bitcoin.pdf."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1093\/itnow\/bwab070","article-title":"Blockchain: The New Art House","volume":"63","author":"Gellman","year":"2021","journal-title":"ITNOW"},{"key":"ref_3","unstructured":"Pocher, N., and Veneris, A. (2022). Handbook on Blockchain, Springer."},{"key":"ref_4","unstructured":"Bilotta, N. (2022, December 31). CBDCs for Dummies: Everything You Need to Know about Central Bank Digital Currency (And Why You Shouldn\u2019t Be Afraid of It). Available online: https:\/\/www.iai.it\/sites\/default\/files\/iaip2124.pdf."},{"key":"ref_5","unstructured":"Urbinati, E., Belsito, A., Cani, D., Caporrini, A., Capotosto, M., Folino, S., Galano, G., Goretti, G., Marcelli, G., and Tiberi, P. (2021). A Digital Euro: A Contribution to the Discussion on Technical Design Choices, Technical Report."},{"key":"ref_6","unstructured":"Kaggle (2022, December 31). ECB Selects External Companies for Joint Prototyping of User Interfaces for a Digital Euro. Available online: https:\/\/www.kaggle.com\/mlg-ulb\/creditcardfraud."},{"key":"ref_7","unstructured":"European Central Bank (ECB) (2022, December 31). Report on a Digital Euro. Available online: https:\/\/www.ecb.europa.eu\/pub\/pdf\/other\/Report_on_a_digital_euro~4d7268b458.en.pdf."},{"key":"ref_8","unstructured":"European Central Bank (ECB) (2022, December 31). A Digital Euro. Available online: https:\/\/www.ecb.europa.eu\/paym\/digital_euro\/html\/index.en.html."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Auer, R., Cornelli, G., and Frost, J. (2020). Rise of the Central Bank Digital Currencies: Drivers Approaches and Technologies, Centre for Economic Policy Research. CEPR Discussion Paper No. DP15363.","DOI":"10.2139\/ssrn.3724070"},{"key":"ref_10","unstructured":"and Kumar, S. (2021, January 24\u201326). Permission blockchain network based central bank digital currency. Proceedings of the 2021 IEEE 4th International Conference on Computing, Power and Communication Technologies (GUCON), Kuala Lumpur, Malaysia."},{"key":"ref_11","unstructured":"Auer, R., and B\u00f6hme, R. (2022, December 31). The Technology of Retail Central Bank Digital Currency. Available online: https:\/\/deliverypdf.ssrn.com\/delivery.php?ID=684088071004065013111111103095008109026012051033042091108125102074072024068074106121101122062000122051045126005099016073065076005049095084082025095122122020124107019019005046078006004010011119127069095101114087122029124085072090121087102081122093123065&EXT=pdf&INDEX=TRUE."},{"key":"ref_12","unstructured":"Bechtel, A., and Otto-Schleicher, D. (2022, December 31). Possible Characteristics of a TIPS-Based Digital Euro. Available online: https:\/\/www.eublockchainforum.eu\/sites\/default\/files\/research-paper\/Bechtel%20Otto-Schleicher%20%282020%29_TIPS-based%20CBDC_1.pdf."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/s40854-018-0097-x","article-title":"Is money going digital? An alternative perspective on the current hype","volume":"4","author":"Reiss","year":"2018","journal-title":"Financ. Innov."},{"key":"ref_14","unstructured":"draft committee chaired by Eleanor Roosevelt, U. (1948). Universal declaration of human rights. UN Gen. Assem., 302, 14\u201325."},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Liu, Y., Zhang, C., Yan, Y., Zhou, X., Tian, Z., and Zhang, J. (2022). A semi-centralized trust management model based on blockchain for data exchange in iot system. IEEE Trans. Serv. Comput.","DOI":"10.1109\/TSC.2022.3181668"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Liu, Y., Yu, W., Ai, Z., Xu, G., Zhao, L., and Tian, Z. (2022). A Blockchain-empowered Federated Learning in Healthcare-based Cyber Physical Systems. IEEE Trans. Netw. Sci. Eng.","DOI":"10.1109\/TNSE.2022.3168025"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"13242","DOI":"10.1109\/TVT.2022.3198004","article-title":"VRepChain: A Decentralized and Privacy-preserving Reputation System for Social Internet of Vehicles Based on Blockchain","volume":"71","author":"Liu","year":"2022","journal-title":"IEEE Trans. Veh. Technol."},{"key":"ref_18","unstructured":"Poon, J., and Dryja, T. (2022, December 31). The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments. Available online: https:\/\/www.bitcoinlightning.com\/wp-content\/uploads\/2018\/03\/lightning-network-paper.pdf."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Kappos, G., Yousaf, H., Piotrowska, A., Kanjalkar, S., Delgado-Segura, S., Miller, A., and Meiklejohn, S. (2021, January 1\u20135). An empirical analysis of privacy in the lightning network. Proceedings of the International Conference on Financial Cryptography and Data Security, Online.","DOI":"10.1007\/978-3-662-64322-8_8"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Akbar, N.A., Muneer, A., ElHakim, N., and Fati, S.M. (2021). Distributed Hybrid Double-Spending Attack Prevention Mechanism for Proof-of-Work and Proof-of-Stake Blockchain Consensuses. Future Internet, 13.","DOI":"10.3390\/fi13110285"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Tso, R., and Lin, C.Y. (2017, January 27\u201329). An off-line mobile payment protocol providing double-spending detection. Proceedings of the 2017 31st International Conference on Advanced Information Networking and Applications Workshops (WAINA), Taipei, Taiwan.","DOI":"10.1109\/WAINA.2017.56"},{"key":"ref_22","doi-asserted-by":"crossref","unstructured":"Zhang, X., and Zhong, C. (2008, January 17\u201319). A Loss Reportable E-Cash Scheme without TTP Based on ECC. Proceedings of the 2008 International Conference on Management of e-Commerce and e-Government, Nanchang, China.","DOI":"10.1109\/ICMECG.2008.56"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Davida, G., Frankel, Y., Tsiounis, Y., and Yung, M. (1997, January 24\u201328). Anonymity control in e-cash systems. Proceedings of the International Conference on Financial Cryptography, Anguilla, British West Indies.","DOI":"10.1007\/3-540-63594-7_63"},{"key":"ref_24","doi-asserted-by":"crossref","unstructured":"Zhang, J., Ma, L., and Wang, Y. (2007, January 15\u201319). Fair e-cash system without trustees for multiple banks. Proceedings of the 2007 International Conference on Computational Intelligence and Security Workshops (CISW 2007), Harbin, China.","DOI":"10.1109\/CISW.2007.4425563"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Ateniese, G., Camenisch, J., Joye, M., and Tsudik, G. (2000, January 20\u201324). A practical and provably secure coalition-resistant group signature scheme. Proceedings of the Annual International Cryptology Conference, Santa Barbara, CA, USA.","DOI":"10.1007\/3-540-44598-6_16"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"103994","DOI":"10.1109\/ACCESS.2020.2998951","article-title":"An Overview on Blockchain for Smartphones: State-of-the-Art, Consensus, Implementation, Challenges and Future Trends","volume":"8","author":"Ometov","year":"2020","journal-title":"IEEE Access"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1007\/s10207-014-0240-2","article-title":"Provably secure E-cash system with practical and efficient complete tracing","volume":"13","author":"Lian","year":"2014","journal-title":"Int. J. Inf. Secur."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Juels, A. (1999, January 22\u201325). Trustee tokens: Simple and practical anonymous digital coin tracing. Proceedings of the International Conference on Financial Cryptography, Anguilla, British West Indies.","DOI":"10.1007\/3-540-48390-X_3"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"118024","DOI":"10.1109\/ACCESS.2022.3218010","article-title":"The role of technology in improving the Customer Experience in the banking sector: A systematic mapping study","volume":"10","author":"Vergallo","year":"2022","journal-title":"IEEE Access"},{"key":"ref_30","unstructured":"Goldwasser, S., Kalai, Y.T., and Rothblum, G.N. (2008, January 17\u201321). One-time programs. Proceedings of the Annual International Cryptology Conference, Santa Barbara, CA, USA."},{"key":"ref_31","unstructured":"Fernandes, A.P., and Lisb\u00f4a, M.L.B. (2001, January 15\u201320). Reflective Implementation of an object recovery design pattern. Proceedings of the VII Congreso Argentino de Ciencias de la Computaci\u00f3n, El Calafate, Santa Cruz, Argentina."},{"key":"ref_32","unstructured":"Support, A. (2022, December 31). Secure Enclave Architecture. Available online: https:\/\/support.apple.com\/it-it\/guide\/security\/sec59b0b31ff\/web."},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Zhao, L., Choi, J.I., Demirag, D., Butler, K.R., Mannan, M., Ayday, E., and Clark, J. (2019, January 18\u201322). One-time programs made practical. Proceedings of the International Conference on Financial Cryptography and Data Security, Frigate Bay, St. Kitts and Nevis.","DOI":"10.1007\/978-3-030-32101-7_37"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41534-021-00435-w","article-title":"Probabilistic one-time programs using quantum entanglement","volume":"7","author":"Roehsner","year":"2021","journal-title":"npj Quantum Inf."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Broadbent, A., Gutoski, G., and Stebila, D. (2013, January 18\u201322). Quantum one-time programs. Proceedings of the Annual Cryptology Conference, Barbara, CA, USA.","DOI":"10.1007\/978-3-642-40084-1_20"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1038\/s41467-018-07591-2","article-title":"Quantum advantage for probabilistic one-time programs","volume":"9","author":"Roehsner","year":"2018","journal-title":"Nat. Commun."},{"key":"ref_37","unstructured":"Apple (2022, December 31). Multipeer Connectivity Framework. Available online: https:\/\/developer.apple.com\/documentation\/multipeerconnectivity."},{"key":"ref_38","doi-asserted-by":"crossref","unstructured":"Ibrahem, M.K. (2012, January 2\u20135). Modification of Diffie\u2013Hellman key exchange algorithm for Zero knowledge proof. Proceedings of the 2012 International Conference on Future Communication Networks, Baghdad, Iraq.","DOI":"10.1109\/ICFCN.2012.6206859"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/3\/1336\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:15:08Z","timestamp":1760120108000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/23\/3\/1336"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,25]]},"references-count":38,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["s23031336"],"URL":"https:\/\/doi.org\/10.3390\/s23031336","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,25]]}}}