一种基于混沌系统的快速序列密码算法

A Fast Stream Cipher Scheme Based on Chaotic System

提出一种基于混沌系统和非线性移位寄存器的快速序列密码算法.该算法利用混沌序列初始化非线性移位寄存器(NFSR)和构造非线性移位寄存器的更新函数,非线性移位寄存器每循环一次输出32 bit密钥流.在NFSR的更新函数中,每输出216bit密钥流混沌Sk(.)盒动态更新一次,也就是混沌系统迭代512次可以连续输出216bit密钥流.对输出的密钥流性能进行数值分析和实验,并对算法的安全性进行分析.结果表明:用该方法可以得到独立、均匀和长周期的密钥流序列,同时可以有效地克服混沌序列在有限精度实现时出现短周期和NLFSR每循环1次输出1 bit密钥流的低效率问题.

Based on chaotic system and non-linear feedback shift register（NLFSR） a fast streamer cipher is proposed.Employing binary sequences generated by chaotic system,the approach initializes NLFSR（Non-linear feedback shift register）and constructs the update function of NLFSR,and the update function,which is called once per round,manipulates the internal state to generate 32 bits of pseudo-random key stream.The chaotic dynamic Box of the update function should be reconstructed at lease once for every bit of key stream generated,that is,iteration 512 times of chaotic system can produces bits of pseudo-random key stream.The theoretical and numerical analyses show that the scheme can not only produce the independently and uniformly distributed key stream,but also improve largely the period of chaotic sequence under the finite-precision circumstances and increase in efficiency.