Quantum coin hedging, and a counter measure

Maor Ganz, Or Sattath

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

A quantum board game is a multi-round protocol between a single quantum player against the quantum board. Molina and Watrous discovered quantum hedging. They gave an example for perfect quantum hedging: a board game with winning probability < 1, such that the player can win with certainty at least 1-out-of-2 quantum board games played in parallel. Here we show that perfect quantum hedging occurs in a cryptographic protocol - quantum coin flipping. For this reason, when cryptographic protocols are composed in parallel, hedging may introduce serious challenges into their analysis. We also show that hedging cannot occur when playing two-outcome board games in sequence. This is done by showing a formula for the value of sequential two-outcome board games, which depends only on the optimal value of a single board game; this formula applies in a more general setting of possible target functions, in which hedging is only a special case.

Original languageEnglish
Title of host publication12th Conference on the Theory of Quantum Computation, Communication, and Cryptography, TQC 2017
EditorsMark M. Wilde
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Pages41-415
Number of pages375
ISBN (Electronic)9783959770347
DOIs
StatePublished - 1 Feb 2018
Externally publishedYes
Event12th Conference on the Theory of Quantum Computation, Communication, and Cryptography, TQC 2017 - Paris, France
Duration: 14 Jun 201716 Jun 2017

Publication series

NameLeibniz International Proceedings in Informatics, LIPIcs
Volume73
ISSN (Print)1868-8969

Conference

Conference12th Conference on the Theory of Quantum Computation, Communication, and Cryptography, TQC 2017
Country/TerritoryFrance
CityParis
Period14/06/1716/06/17

Keywords

  • Quantum coin-flipping
  • Quantum cryptography
  • Quantum hedging

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