Quantum stream cipher part IV: effects of the deliberate signal randomization and the deliberate error randomization
Kentaro Kato, Osamu Hirota · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2006
In a series of articles concerned with quantum stream cipher by Y-00 protocol on this conference, we have claimed that the quantum stream cipher has a pretty good security against several concrete attacks. On the other hand, it has been pointed out that one can improve the security level by using various additional randomization techniques. In this paper, we will show some concrete randomization techniques for quantum stream cipher. First we will sketch the framework of the deliberate signal randomization (DSR) that is realized by randomizing the signals deliberately with true-random numbers or with pseud-random numbers generated by a secret key. Secondly, we will consider about the deliberate error randomization (DER) by using concrete models. It will be shown that these randomization techniques enhance the security level of the quantum stream cipher.