2016/01/31 by Jędrzej Kaniewski, Stephanie Wehner · 42 citations
Computer Science · Physics and Astronomy · #Adversary #Alice (programming language) #Alice and Bob #Computer science #Computer security #Cryptographic protocol #Cryptography #Cryptography and Data Security #Physics #Protocol (science) #Quantum #Quantum Information and Cryptography #Quantum Mechanics and Applications #Quantum cryptography #Quantum information #Quantum mechanics #String (physics) #Theoretical computer science #Theoretical physics #quant-ph
paper · pdf · doi:10.1088/1367-2630/18/5/055004
published in New Journal of Physics 18(5), 055004 (IOP Publishing) · 18 pages, 7 figures, published version
openalex publication_date 2016/05/06 · arxiv created 2016/05/09 · arxiv updated 2016/05/10 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
The goal of two-party cryptography is to enable two parties, Alice and Bob, to solve common tasks without the need for mutual trust. Examples of such tasks are private access to a database, and secure identification. Quantum communication enables security for all of these problems in the noisy-storage model by sending more signals than the adversary can store in a certain time frame. Here, we initiate the study of device-independent (DI) protocols for two-party cryptography in the noisy-storage model. Specifically, we present a relatively easy to implement protocol for a cryptographic building block known as weak string erasure and prove its security even if the devices used in the protocol are prepared by the dishonest party. DI two-party cryptography is made challenging by the fact that Alice and Bob do not trust each other, which requires new techniques to establish security. We fully analyse the case of memoryless devices (for which sequential attacks are optimal) and the case of sequential attacks for arbitrary devices. The key ingredient of the proof, which might be of independent interest, is an explicit (and tight) relation between the violation of the Clauser–Horne–Shimony–Holt inequality observed by Alice and Bob and uncertainty generated by Alice against Bob who is forced to measure his system before finding out Alice's setting (guessing with postmeasurement information). In particular, we show that security is possible for arbitrarily small violation.