Quantum key distribution (QKD) protocols make it possible for two parties to generate a secret shared key. One of the most important QKD protocols, BB84, was suggested by Bennett and Brassard in 1984. Various proofs of unconditional security for BB84 have been suggested, but the first security proofs were not composable. Here we improve a security proof of BB84 given by [Biham, Boyer, Boykin, Mor, and Roychowdhury, J. Cryptology, 19(4):381-439, 2006] to be composable and match the state-of-the-art results for BB84, and we extend it to prove unconditional security of several variants of the BB84 protocol. Our composable security proof for BB84 and its variants is mostly self-contained, algebraic, and relatively simple, and it gives tight finite-key bounds.
翻译:1984年Bennett和Brassard提出了最重要的QKD协议之一,即BB84协议。提出了BB84协议的无条件安全的各种证明,但第一批安全证明是不可比较的。我们在这里改进了BB84协议的安全证明,这是由[Biham、Boyer、Boykin、Mor和Roychowdhury、J.Cocoptology,19(4):381-439,2006] 提供的,以便可以进行和解并符合BB84协议的最新结果,我们将其扩展以证明BB84协议的若干变体的无条件安全。我们BB84协议及其变体的可复写安全证明大部分是自成的、代数和相对简单的,它提供了严格的有限界限。