两方量子密钥协商协议的改进

Improvement of a two-party quantum key agreement protocol

针对Hsueh和Chen的基于最大纠缠态两方量子密钥协商协议存在安全漏洞,即发送方可单方控制共享密钥的问题,通过增加接收方的幺正操作给出了一个改进方案.利用幺正操作来代替对发送方的安全检测,这从根本上满足了量子密钥协商中各参与者都贡献于共享密钥的生成和分配这一基本要求,从而使其抗发送方攻击的安全性依赖于基本物理原理而非检测光子技术.安全分析表明,该方案可有效抵抗外部攻击和参与者攻击.与另一改进方案相比,该方案以更小的代价解决了原协议的漏洞,提高了协议效率.

To avoid the weakness that the sender can fully control the shared key alone in the Hsueh and Chen＇s two-party quantum key agreement （QKA） protocol with maximally entangled states, a possible solution is presented by adding the receiver＇s unitary operation. The unitary operation instead of the security checking is utilized, which makes this protocol fundamentally meet the basic requirement that in a quantum key agreement each participant equally contribute to the generation and distribution of the shared key. Therefore the security against the participant attack is based on basic physical principles rather than on the checking photons technique. Security analysis shows that this protocol is secure against the outside attack and participant attack. Compared with the previous improved protocol, the weakness is avoided with less qubits and the efficiency of the protocol is improved.