摘要
本文发现了迭代型混沌密码的一个新信息泄漏规律,即对每个时刻i,由乱数序列求出的混沌映射在该时刻的可能输入(及可能密钥参数)全体都可用若干个区间的并集简单描述,且对多对一混沌映射而言,每个区间内都有等效解的概率很大,并随着时刻i的减小,区间的长度急剧缩短.基于该信息泄漏规律,本文提出了攻击迭代型混沌密码的一个新方法,即逆推压缩攻击方法.在一定的条件下,该攻击方法的成功率为1,且计算复杂性、存储复杂性和数据复杂性都是密钥规模的线性函数.本文对廖旎焕等人在2006年发表的混沌扩频序列密码算法在密钥规模为64比特时做了100例攻击实验,每例实验平均仅需0.11秒就可求出等效密钥,从而验证了逆推压缩攻击方法的有效性和正确性.与现有的攻击混沌密码的一般方法相比,本文提出的方法是首个复杂性为密钥长度线性量级的攻击方法.
In this paper,we find a new law of information leaking out.We find that for each clock i,all possible inputs（and the parameter-formed key） of a chaotic map at the i-th clock which can produce the key stream forms an union of intervals,and the probability that each interval includes an equivalent solution is very high for many-to-one chaotic maps,and the length of intervals are decreased exponentially as the clock i decrease.Based on the new law of information leaking out,an inversion and compression attack to iterative chaotic ciphers is proposed for the first time.Under some conditions,the success rate of the attack is 1 and the computational complexity,the memory complexity and the data complexity are linear on the length of key.100 experiments to the chaotic spreading sequences algorithm,presented by Liao Ni-huan et al in 2006,were done for 64 bits keys at a 2.5GHz of Pentium 4 PC.Each experiment just costs about 0.11 seconds in average,which implies the correctness and validity of our attack algorithm.Comparison with the known attack to chaotic ciphers,the inversion and compression attack is the first general attack that the complexity is linear on the length of key.
出处
《电子学报》
EI
CAS
CSCD
北大核心
2010年第1期129-134,140,共7页
Acta Electronica Sinica
基金
河南省杰出青年科学基金(No.0312001800)
关键词
混沌密码
密码分析
逆推压缩攻击
等效密钥
chaotic cipher cryptanalysis inversion and compression attack equivalent key
