Miller Carl A, Shi Yaoyun
National Institute of Standards and Technology, 100 Bureau Dr., Gaithersburg, MD 20890, USA, Joint Center for Quantum Information and Computer Science, University of Maryland, College Park, MD 20742, USA.
Dept. of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA.
Quantum Inf Comput. 2017 Jun;17(7):595-610.
If two quantum players at a nonlocal game achieve a superclassical score, then their measurement outcomes must be at least partially random from the perspective of any third player. This is the basis for device-independent quantum cryptography. In this paper we address a related question: does a superclassical score at guarantee that one player has created randomness from the perspective of the other player? We show that for complete-support games, the answer is yes: even if the second player is given the first player's input at the conclusion of the game, he cannot perfectly recover her output. Thus some amount of randomness (i.e., randomness possessed by only one player) is always obtained when randomness is certified from nonlocal games with quantum strategies. This is in contrast to non-signaling game strategies, which may produce global randomness without any local randomness. We discuss potential implications for cryptographic protocols between mistrustful parties.
如果非局域博弈中的两个量子参与者获得了超经典分数，那么从任何第三方参与者的角度来看，他们的测量结果必然至少部分是随机的。这是与设备无关的量子密码学的基础。在本文中，我们探讨一个相关问题：在非局域博弈中获得超经典分数是否能保证从一方参与者的角度来看，另一方参与者产生了随机性？我们表明，对于完全支持的博弈，答案是肯定的：即使在博弈结束时将第一个参与者的输入提供给第二个参与者，他也无法完美恢复她的输出。因此，当通过量子策略从非局域博弈中验证随机性时，总会获得一定量的随机性（即仅由一方参与者拥有的随机性）。这与非信号博弈策略形成对比，后者可能产生全局随机性而不产生任何局部随机性。我们讨论了对不信任方之间的密码协议的潜在影响。
