Analysis of statistical characteristics for quantum noise stream cipher

摘要

The statistical characteristics of quantum noise stream cipher system is investigated. Simulation results shows that with the variance of the noise σ~2 is changed from 0 to 0.3, the statistical parameter of signals decreases to the floor. When the variance of the noise is more than noise masking threshold, the statistical characteristic of signals is completely submerged in noise. Moreover, when the variance of the noise is equal to {0.001, 0.01}, P_b =1 is unchanged with the increase of modulation order. Furthermore, when the variance of the noise is equal to {0.1, 0.2}, the correct probability for Bob P_b decreases to a fixed value which is 0.99 and 0.79, respectively. Correspondingly, the correct probability for Eve P_e decreases to 0 with the modulation order increasing. And the channel advantage for main channel over wiretap channel can be formed by combining proper modulation order with noise.