期刊名称：Chicago Journal of Theoretical Computer Science
印刷版ISSN：1073-0486
出版年度：2016
卷号：2016
页码：1-17
出版社：MIT Press ; University of Chicago, Department of Computer Science
摘要：Oblivious transfer is a fundamental cryptographic primitive in which Bob transfers one of two bits to Alice in such a way that Bob cannot know which of the two bits Alice has learned. We present an optimal security bound for quantum oblivious transfer protocols, in the information theoretic setting, under a natural and {arguably} demanding definition of what it means for Alice to cheat. Our lower bound is a smooth tradeoff between the probability $P^*_{Bob}$ with which Bob can guess Alice's bit choice and the probability $P^*_{Alice}$ with which Alice can guess both of Bob's bits given that she learns one of the bits with certainty. We prove that $2 P^*_{Bob} + P^*_{Alice} \geq 2$ in any quantum protocol for oblivious transfer, from which it follows that one of the two parties must be able to cheat with probability at least $2/3$. We prove that this bound is optimal by exhibiting a family of protocols whose cheating probabilities can be made arbitrarily close to any point on the tradeoff curve
