基于BB84协议,利用挑战-应答机制,提出了一种量子密钥分发协议。发送 方Alice和接收方Bob通过安全信道共享三个不同的Hash函数(H1,H2和H3), 以及随机比特串SAB0。 在每次密钥分发时,Alice产生随机比特串SAr(挑战信息)和SAk(密钥),结合H1和SAB0,基 于BB84协议产生光子串SAp; Alice将SAr和SAp发送给Bob,Bob接收 到对应的SBr和光子串SBp; Bob利用SBr,结合H1和SAB0,基于 BB84协议对光子串SBp进行测量得到SBk。理想情况下共享密钥SAr=SBr。 另外,Bob利用SBr,SBk,SAB0及H2产生应答序列SB2; Alice和Bob利用各 自拥有的序列及H3分别产生序列S~A0和S~B0,并对各 自的SAB0做更新。在密钥分发过程中光子的利用率为100%,该协议既有BB84协议类似的安全性,又有单向身份认证功能。

A quantum key distribution protocol based on BB84 protocol and a challenge-response mechanism was proposed. Through a secure channel, Alice and Bob have pre-shared three different Hash functions (denoted by H1, H2 and H3) and a random bit string SAB0. Every time, Alice first generates two random bit strings SAr (challenge) and SAk (key), then prepares a photon sequence SAp based on BB84 protocol using SBr,SBk,SAB0 and H1. Alice sends SAr and SAp to Bob and Bob receives the corresponding SBr and SBp. Bob measures SBp according to BB84 protocol and gets corresponding SBk. In the ideal case, SAk should be the same as SBk. Bob uses SBr,SBk,SAB0 and H2 to generate SB2 (response). At last, Alice and Bob use their own sequences and H3 to generate S~A0 and S~B0 respectively, then they update their own SAB0. In the proposed protocol, the utilization rate of photons is 100%. The security of the protocol is similar as that of the BB84 protocol. Furthermore, it is a one-way identification authentication protocol.