TY - JOUR
TI - SoK: Communication Across Distributed Ledgers
AU - Zamyatin, A.
AU - Al-Bassam, M.
AU - Zindros, D.
AU - Kokoris-Kogias, E.
AU - Moreno-Sanchez, P.
AU - Kiayias, A.
AU - Knottenbelt, W.J.
JO - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
PY - 2021
VL - 12675 LNCS
TODO - null
SP - 3-36
PB - Springer Science and Business Media Deutschland GmbH
SN - null
TODO - 10.1007/978-3-662-64331-0_1
TODO - Chromium compounds;  Cryptography;  Distributed ledger, Block-chain;  Communication research;  Communications protocols;  Composability;  Existing systems;  External systems;  Research problems;  Side-chains;  Trust assumptions;  Trusted third parties, Blockchain
TODO - 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. © 2021, International Financial Cryptography Association.
ER -