Abstract:

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.

Key words: linear congruence algorithm;linear congruence comparator;Chaos system;finite precision effect