本文基于线性同余原理,设计一种线性同余比较器.该同余比较器将两个独立的线性同余生成器结合起来,用一个比较器来控制输出.将输出序列作为扰动信号,以异或函数叠加到混沌轨道来改善混沌系统生成序列的随机性.分析攻击者通过线性同余比较器生成序列来破解种子密钥的计算复杂度,及加入随机扰动后的混沌序列的平衡度、相关性及初值敏感性,结果表明,计算复杂度是呈指数幂增长的,线性同余比较器生成序列具有前向和后向不可预测性,并且该密钥流生成器具有较大的密钥空间,可以生成具有良好随机性的序列,可以有效地克服混沌序列在有限精度实现时出现的短周期问题.%Based on linear congruence theory, a linear congruence comparator constructed by two independent linear congruence generators and a simple comparator are designed. As a disturbance signal, the output sequence of the linear congruence comparator is superimposed to the chaotic orbit to improve its pseudo-randomness. The analytical results of the computational complexity that the attacker cracks the seed key by intercepting the output sequence of the linear congruence comparator, the balance, correlation and sensitivity to the initial conditions of chaotic sequence after adding random perturbations, show that the computational complexity features power exponential growth, and the output sequence has forward and backward unpredictability. The key stream generator with a larger key space can generate good pseudo-randomness sequences, and effectively overcome the short period problem of the chaotic sequence in the case of finite precision.
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