{"department":[{"_id":"ElKo"}],"abstract":[{"text":"Since the inception of Bitcoin, a plethora of distributed ledgers differing in design and purpose has been created. While by design, blockchains provide no means to securely communicate with external systems, numerous attempts towards trustless cross-chain communication have been proposed over the years. Today, cross-chain communication (CCC) plays a fundamental role in cryptocurrency exchanges, scalability efforts via sharding, extension of existing systems through sidechains, and bootstrapping of new blockchains. Unfortunately, existing proposals are designed ad-hoc for specific use-cases, making it hard to gain confidence in their correctness and composability. We provide the first systematic exposition of cross-chain communication protocols. We formalize the underlying research problem and show that CCC is impossible without a trusted third party, contrary to common beliefs in the blockchain community. With this result in mind, we develop a framework to design new and evaluate existing CCC protocols, focusing on the inherent trust assumptions thereof, and derive a classification covering the field of cross-chain communication to date. We conclude by discussing open challenges for CCC research and the implications of interoperability on the security and privacy of blockchains.","lang":"eng"}],"main_file_link":[{"url":"https://eprint.iacr.org/2019/1128","open_access":"1"}],"date_published":"2021-10-23T00:00:00Z","publication_status":"published","article_processing_charge":"No","month":"10","date_updated":"2023-08-14T12:59:26Z","type":"conference","day":"23","alternative_title":["LNCS"],"title":"SoK: Communication across distributed ledgers","quality_controlled":"1","status":"public","publisher":"Springer Nature","scopus_import":"1","oa":1,"oa_version":"Preprint","user_id":"4359f0d1-fa6c-11eb-b949-802e58b17ae8","date_created":"2021-11-21T23:01:29Z","language":[{"iso":"eng"}],"_id":"10325","conference":{"start_date":"2021-03-01","name":"FC: Financial Cryptography","location":"Virtual","end_date":"2021-03-05"},"citation":{"ieee":"A. Zamyatin <i>et al.</i>, “SoK: Communication across distributed ledgers,” in <i>25th International Conference on Financial Cryptography and Data Security</i>, Virtual, 2021, vol. 12675, pp. 3–36.","mla":"Zamyatin, Alexei, et al. “SoK: Communication across Distributed Ledgers.” <i>25th International Conference on Financial Cryptography and Data Security</i>, vol. 12675, Springer Nature, 2021, pp. 3–36, doi:<a href=\"https://doi.org/10.1007/978-3-662-64331-0_1\">10.1007/978-3-662-64331-0_1</a>.","short":"A. Zamyatin, M. Al-Bassam, D. Zindros, E. Kokoris Kogias, P. Moreno-Sanchez, A. Kiayias, W.J. Knottenbelt, in:, 25th International Conference on Financial Cryptography and Data Security, Springer Nature, 2021, pp. 3–36.","ista":"Zamyatin A, Al-Bassam M, Zindros D, Kokoris Kogias E, Moreno-Sanchez P, Kiayias A, Knottenbelt WJ. 2021. SoK: Communication across distributed ledgers. 25th International Conference on Financial Cryptography and Data Security. FC: Financial Cryptography, LNCS, vol. 12675, 3–36.","chicago":"Zamyatin, Alexei, Mustafa Al-Bassam, Dionysis Zindros, Eleftherios Kokoris Kogias, Pedro Moreno-Sanchez, Aggelos Kiayias, and William J. Knottenbelt. “SoK: Communication across Distributed Ledgers.” In <i>25th International Conference on Financial Cryptography and Data Security</i>, 12675:3–36. Springer Nature, 2021. <a href=\"https://doi.org/10.1007/978-3-662-64331-0_1\">https://doi.org/10.1007/978-3-662-64331-0_1</a>.","apa":"Zamyatin, A., Al-Bassam, M., Zindros, D., Kokoris Kogias, E., Moreno-Sanchez, P., Kiayias, A., &#38; Knottenbelt, W. J. (2021). SoK: Communication across distributed ledgers. In <i>25th International Conference on Financial Cryptography and Data Security</i> (Vol. 12675, pp. 3–36). Virtual: Springer Nature. <a href=\"https://doi.org/10.1007/978-3-662-64331-0_1\">https://doi.org/10.1007/978-3-662-64331-0_1</a>","ama":"Zamyatin A, Al-Bassam M, Zindros D, et al. SoK: Communication across distributed ledgers. In: <i>25th International Conference on Financial Cryptography and Data Security</i>. Vol 12675. Springer Nature; 2021:3-36. doi:<a href=\"https://doi.org/10.1007/978-3-662-64331-0_1\">10.1007/978-3-662-64331-0_1</a>"},"external_id":{"isi":["000712016200001"]},"publication_identifier":{"issn":["0302-9743"],"isbn":["9-783-6626-4330-3"],"eissn":["1611-3349"],"eisbn":["978-3-662-64331-0"]},"doi":"10.1007/978-3-662-64331-0_1","page":"3-36","author":[{"full_name":"Zamyatin, Alexei","first_name":"Alexei","last_name":"Zamyatin"},{"full_name":"Al-Bassam, Mustafa","last_name":"Al-Bassam","first_name":"Mustafa"},{"full_name":"Zindros, Dionysis","last_name":"Zindros","first_name":"Dionysis"},{"id":"f5983044-d7ef-11ea-ac6d-fd1430a26d30","full_name":"Kokoris Kogias, Eleftherios","last_name":"Kokoris Kogias","first_name":"Eleftherios"},{"last_name":"Moreno-Sanchez","first_name":"Pedro","full_name":"Moreno-Sanchez, Pedro"},{"full_name":"Kiayias, Aggelos","first_name":"Aggelos","last_name":"Kiayias"},{"first_name":"William J.","last_name":"Knottenbelt","full_name":"Knottenbelt, William J."}],"publication":"25th International Conference on Financial Cryptography and Data Security","isi":1,"acknowledgement":"We would like express our gratitude to Georgia Avarikioti, Daniel Perez and Dominik Harz for helpful comments and feedback on earlier versions of this manuscript. We also thank Nicholas Stifter, Aljosha Judmayer, Philipp Schindler, Edgar Weippl, and Alistair Stewart for insightful discussions during the early stages of this research. We also wish to thank the anonymous reviewers for their valuable comments that helped improve the presentation of our results. This research was funded by Bridge 1 858561 SESC; Bridge 1 864738 PR4DLT (all FFG); the Christian Doppler Laboratory for Security and Quality Improvement in the Production System Lifecycle (CDL-SQI); the competence center SBA-K1 funded by COMET; Chaincode Labs through the project SLN: Scalability for the Lightning Network; and by the Austrian Science Fund (FWF) through the Meitner program (project M-2608). Mustafa Al-Bassam is funded by a scholarship from the Alan Turing Institute. Alexei Zamyatin conducted the early stages of this work during his time at SBA Research, and was supported by a Binance Research Fellowship.","year":"2021","volume":"12675 "}