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.