用量子筛选码直接进行秘密通信  

Direct Private Communication Using Quantum Sifted Keys

作　　者：廖常俊[1] 刘颂豪[1] 郑力明[2] 

机构地区：[1]华南师范大学信息光电子科技学院光子信息技术广东省高校重点实验室,广东广州510631 [2]暨南大学电子工程系,广东广州510632

出　　处：《量子光学学报》2008年第2期165-173,共9页Journal of Quantum Optics

基　　金：国家973计划(G2001039302);广东省科技专项(2003A10305)

摘　　要：提出与身分认证的同时进行单向通信密码校正方法,由此可以实现用量子筛选码的直接秘密通信。本方法用周期结构的破损报告错误信息。具体操作时,发信方用"一次一密"的方式发送信息,重复的信息由不同密码加密。在误码率在允许的范围内,合法收信方用量子筛选码和收到的密文就能发现某种周期结构,由此就可自己校正其中的错误了。结果是误码的定位和校正,误码率的测量,安全性的判断,身份的认证可以一次性地完成了。计算中产生的误码矩阵,等效于一种特殊的密钥,只有合法的收信方能根据安全地收到的量子筛选码准确地得到。这个误码矩阵可以用于校正密钥,也可以直接用于校正收到的文件。这个通信过程对双方是对称的。收信方也可以用他的量子筛选码以一次一密的方式加密有周期结构的信息回答发信方,她可以按照完全相同的方式找到误码矩阵,完成一次无差错的秘密通信。本方法不需要存储正确的密钥,也因此没有存储密钥被复制的危险。Error correction is a necessary step in quantum cryptography since the quantum bit error rate （QBER） is thought as unavoidable as the practical quantum system containing probability unknown in phase and amplitude. These errors come from the experimental imperfection even if there is no exist of eavesdroppers. The error correction protocol used today is based on two-way communication via classical channel that leads to reduction of the key rate. The distilled bits available for practical encryption will decrease further after private amplification and authentication. This paper proposes one-way correction that can combine the authentication and correction altogether. This protocol is based on periodic structure analysis that any defect in the periodic structure reports an error so that the error is correctly allocated. Theoretical and digital simulation demonstrated that this protocol makes direct private communication possible by using quantum sifted keys. In this protocol the quantum sifted keys before correction was divided into two parts. The first part is used for authentication. In practice, Alice encoded her question several times with different quantum sifted key in a manner same as ＂ one-time-pad＂. Bob can recognize her question only if had he made correction of his quantum sifted keys. Bob does his bit error correction by himself with the cryptogram he received and his sifted keys only if the error bit rate is allowable since some kind of periodic structure can be found in the decrypted text. By comparison of the periodic features of the bit strings he can allocate the error bit and calculate error bite rate that is possible to lead to a correction of the error bits without any reduction of the key. After his error correction for the decrypted text he can recognize Alice＇ s question and makes a correct answer to her. The answer may be encoded with his corrected key and then send back to Alice. Alice is easy to check if Bob has perfectly responded. The sifted keys should be abandoned if the QBER

关 键 词：QBER 误码校正 量子密码术 身份认证 量子筛选码 

分 类 号：O431[机械工程—光学工程]