{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,22]],"date-time":"2026-04-22T17:40:53Z","timestamp":1776879653099,"version":"3.51.2"},"reference-count":25,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2018,8,20]],"date-time":"2018-08-20T00:00:00Z","timestamp":1534723200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100003406","name":"Tekes","doi-asserted-by":"publisher","award":["VitalSens project"],"award-info":[{"award-number":["VitalSens project"]}],"id":[{"id":"10.13039\/501100003406","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Cryptography"],"abstract":"<jats:p>Blockchain is a public open ledger that provides data integrity in a distributed manner. It is the underlying technology of cryptocurrencies and an increasing number of related applications, such as smart contracts. The open nature of blockchain together with strong integrity guarantees on the stored data makes it a compelling platform for covert communication. In this paper, we suggest a method of securely embedding covert messages into a blockchain. We formulate a simplified ideal blockchain model based on existing implementations and devise a protocol that enables two parties to covertly communicate through the blockchain following that model. We also formulate a rigorous definition for the security and covertness of such a protocol based on computational indistinguishability. Finally, we show that our method satisfies this definition in the random oracle model for the underlying cryptographic hash function.<\/jats:p>","DOI":"10.3390\/cryptography2030018","type":"journal-article","created":{"date-parts":[[2018,8,20]],"date-time":"2018-08-20T11:23:06Z","timestamp":1534764186000},"page":"18","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":114,"title":["Provably Secure Covert Communication on Blockchain"],"prefix":"10.3390","volume":"2","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-8181-5604","authenticated-orcid":false,"given":"Juha","family":"Partala","sequence":"first","affiliation":[{"name":"Physiological Signal Analysis Team, Center for Machine Vision and Signal Analysis, University of Oulu, P.O. Box 5000, FI-90014 Oulu, Finland"}]}],"member":"1968","published-online":{"date-parts":[[2018,8,20]]},"reference":[{"key":"ref_1","unstructured":"Nakamoto, S. (2018, February 12). Bitcoin: A Peer-to-Peer Electronic Cash System. Available online: https:\/\/bitcoin.org\/bitcoin.pdf."},{"key":"ref_2","unstructured":"Wood, G. (2018, February 13). Ethereum: A Secure Decentralized Transaction Ledger. Available online: http:\/\/gavwood.com\/paper.pdf."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2292","DOI":"10.1109\/ACCESS.2016.2566339","article-title":"Blockchains and Smart Contracts for the Internet of Things","volume":"4","author":"Christidis","year":"2016","journal-title":"IEEE Access"},{"key":"ref_4","doi-asserted-by":"crossref","unstructured":"Mettler, M. (2016, January 14\u201316). Blockchain technology in healthcare: The revolution starts here. Proceedings of the 2016 IEEE 18th International Conference on e-Health Networking, Applications and Services (Healthcom), Munich, Germany.","DOI":"10.1109\/HealthCom.2016.7749510"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Azaria, A., Ekblaw, A., Vieira, T., and Lippman, A. 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Proceedings of the 2018 IEEE International Conference on Cloud Engineering (IC2E), Orlando, FL, USA.","DOI":"10.1109\/IC2E.2018.00070"},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"Keromytis, A.D. (2012). Bitter to Better\u2014How to Make Bitcoin a Better Currency. Financial Cryptography and Data Security, Springer.","DOI":"10.1007\/978-3-642-32946-3"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Miers, I., Garman, C., Green, M., and Rubin, A.D. (2013, January 19\u201322). Zerocoin: Anonymous Distributed E-Cash from Bitcoin. Proceedings of the 2013 IEEE Symposium on Security and Privacy, Berkeley, CA, USA.","DOI":"10.1109\/SP.2013.34"},{"key":"ref_10","unstructured":"Sasson, E.B., Chiesa, A., Garman, C., Green, M., Miers, I., Tromer, E., and Virza, M. (2014, January 18\u201321). Zerocash: Decentralized Anonymous Payments from Bitcoin. 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Comput."},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Shafagh, H., Burkhalter, L., Hithnawi, A., and Duquennoy, S. (2017, January 3). Towards Blockchain-based Auditable Storage and Sharing of IoT Data. Proceedings of the 2017 on Cloud Computing Security Workshop, CCSW \u201917, Dallas, TX, USA.","DOI":"10.1145\/3140649.3140656"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Bhowmik, D., and Feng, T. (2017, January 23\u201325). The multimedia blockchain: A distributed and tamper-proof media transaction framework. Proceedings of the 2017 22nd International Conference on Digital Signal Processing (DSP), London, UK.","DOI":"10.1109\/ICDSP.2017.8096051"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1137\/0217017","article-title":"A digital signature scheme secure against adaptive chosen-message attacks","volume":"17","author":"Goldwasser","year":"1988","journal-title":"SIAM J. 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Bitcoin Transaction Graph Analysis, ArXiv."}],"container-title":["Cryptography"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2410-387X\/2\/3\/18\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T15:19:50Z","timestamp":1760195990000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2410-387X\/2\/3\/18"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2018,8,20]]},"references-count":25,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2018,9]]}},"alternative-id":["cryptography2030018"],"URL":"https:\/\/doi.org\/10.3390\/cryptography2030018","relation":{},"ISSN":["2410-387X"],"issn-type":[{"value":"2410-387X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2018,8,20]]}}}