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Secure bit commitment from relativistic constraints


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Title Secure bit commitment from relativistic constraints
Title of Series The Annual Conference on Quantum Cryptography (QCRYPT) 2012
Number of Parts 30
Author Kaniewski, Jędrzej
Contributors Centre for Quantum Technologies (CQT)
National University of Singapore (NUS)
License CC Attribution - NonCommercial - NoDerivatives 2.5 Switzerland:
You are free to use, copy, distribute and transmit the work or content in unchanged form for any legal and non-commercial purpose as long as the work is attributed to the author in the manner specified by the author or licensor.
DOI 10.5446/36677
Publisher Eidgenössische Technische Hochschule (ETH) Zürich
Release Date 2012
Language English

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Subject Area Information technology
Abstract We investigate two-party cryptographic protocols that are secure under assumptions motivated by physics, namely relativistic assumptions (no-signalling) and quantum mechanics. In particular, we discuss split models, i.e. models in which certain parties are not allowed to communicate during certain phases of the protocol, for the purpose of bit commitment. We find the minimal splits that are necessary to evade the Mayers-Lo-Chau no-go argument and present protocols that achieve security in these split models. Furthermore, we introduce the notion of local versus global commands, a subtle issue that arises when the split committer is required to delegate agents to perform the open phase separately, without communication. We argue that classical protocols are insecure in the global command model, even when the committer is split. On the other hand, we provide a rigorous security proof in the global command model for a quantum protocol proposed by Kent. The proof employs two fundamental principles of modern physics, the no-signalling property of relativity and the uncertainty principle of quantum mechanics.


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