输出-密文混和反馈混沌流密码的设计

针对利用混沌轨道信息的密码分析，设计了一种输出-密文混和反馈模式的混沌流密码.使用一类区间数目参数化的分段线性混沌映射，通过多次迭代此类映射产生混沌信号.混沌信号的奇数位用来生成密钥流，偶数位和密文合并后作为后续状态反馈给密钥流发生器.在有限精度实现时，通过引入m序列扰动，克服混沌系统的有限精度效应对密钥流的影响.理论分析和试验结果表明，产生的密钥流具有良好的统计特性，密码系统是安全的，便于软硬件实现；并且可以在算法级调节加密速度，满足不同应用的速度要求.

Design of chaotic output-cipher feedback stream cryptosystems

The chaotic output-cipher feedback mode(OCFM) stream cipher was developed to resist attacks based on chaotic orbits.The chaotic signals were generated based on iterating the piecewise linear chaotic map(PLCM) with a segment number parameter(SNP).Odd bits were used to produce the key streams.After being incorporated,the even bits and ciphers were fed back as the next state of the key stream generator.When the chaotic systems were realized with finite precision,the perturbation approach was applied to remedy the finite precision effect,and the perturbation signal was m-sequence.Theoretical analysis and experimental results show that the OCFM cipher is secure and easy to be realized by hardware or software,and that the encryption speed can be adjusted to meet the application requirement at the algorithm level.