TY - GEN
T1 - Quantum coin hedging, and a counter measure
AU - Ganz, Maor
AU - Sattath, Or
N1 - Funding Information:
This work was supported by ERC Grant 030-8301.
Funding Information:
∗ This work was supported by ERC Grant 030-8301. 1 Previous works which studied this setting did not introduce a specific term for it [22]. Other, related notions are interactive proof system, that differ from quantum board games since the verifier and prover receive an input, and from quantum games since usually we think of the players, Alice and Bob, as having symmetric roles, whereas here, the player knows that the board only implements the rules of the game, and uses its specified strategy.
Publisher Copyright:
© Maor Ganz and Or Sattath; licensed under Creative Commons License CC-BY 12th Conference on the Theory of Quantum Computation, Communication, and Cryptography (TQC 2017).
PY - 2018/2/1
Y1 - 2018/2/1
N2 - 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.
AB - 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.
KW - Quantum coin-flipping
KW - Quantum cryptography
KW - Quantum hedging
UR - http://www.scopus.com/inward/record.url?scp=85045459220&partnerID=8YFLogxK
U2 - 10.4230/LIPIcs.TQC.2017.4
DO - 10.4230/LIPIcs.TQC.2017.4
M3 - Conference contribution
AN - SCOPUS:85045459220
T3 - Leibniz International Proceedings in Informatics, LIPIcs
SP - 41
EP - 415
BT - 12th Conference on the Theory of Quantum Computation, Communication, and Cryptography, TQC 2017
A2 - Wilde, Mark M.
PB - Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
T2 - 12th Conference on the Theory of Quantum Computation, Communication, and Cryptography, TQC 2017
Y2 - 14 June 2017 through 16 June 2017
ER -