Shor-Preskill方法不能直接证明B92量子密钥分配协议

The Shor-Preskill Method Is Inapplicable to B92 Protocol

密钥分配协议安全性的证明是确保密钥分配绝对安全的要求 ,经典密码方案的安全性大多难以证明 ,而利用量子力学的基本原理 ,可以证明量子密码方案是无条件安全的。介绍了Shor Preskill对BB84量子密钥分配协议无条件安全性的证明方法 ,归纳了其技巧和特点 ,揭示了对称化方法和量子纠缠提纯技术在该方法中的作用。证明了Shor Preskill方法不能直接用来证明B92协议的无条件安全性。提出了利用Shor Preskill方法间接证明B92的可能途径。

To ensure absolute security of key distribution, each key distribution scheme must be proved. While the security of most classical cipher schemes cannot be proved, the security of quantum cipher schemes is guaranteed by quantum mechanics and can be strictly proved. Shor Preskill's method with which the unconditional security of BB84 quantum key distribution scheme is proved is introduced first. Its techniques and features are summarized and the subtleties of using symmetrization and quantum entanglement purification (QEP) to reduce a QEP based BB84 to a CSS based BB84, and of using the property of CSS code to reduce the CSS based BB84 to standard BB84 protocol are revealed. Then it is proved that Shor preskill's method cannot be applied to B92 protocol directly. A possible solution to prove the unconditional security of B92 using Shor Preskill's method indirectly is proposed.