对DLWX混沌密码算法的分割攻击

分析基于混沌的视频加密算法的安全性，该算法是由混沌映射构造的移位密码，给出对该移位密码的攻击方法并且恢复出混沌映射产生的量化序列。混沌映射产生的量化序列具有前几个量化值对混沌初始值的低位比特变化不够敏感的性质，提出由量化序列恢复混沌初始值的分割攻击方法。在密钥长度为56bit并且参数k=4和r=4的条件下，分割攻击算法的成功率为0．9171，计算复杂性约为2^28，存储复杂性约为2^20。

Divide-and-Conquer Attack on DLWX Chaotic Cipher Algorithm

A chaotic cipher is analyzed. This cipher is a shift cipher constructed by chaotic mapping. A known plaintext attack on the shift cipher is presented to recover the quantified sequence generated by chaotic mapping. The first several bits of quantified sequence are not sensitive to the least significant bits of chaos initial state. A divide-and-conquer attack to recover the chaos initial state from the quantified sequence is proposed. When the parameter k=4, r=4 and the length of key is 56 bit, the success probability of the divide-and-conquer attack is 0.917 1, the computational complexity is about 228, and the memory complexity is about 220.