对DES线性攻击的改进算法

Improved algorithm for linear cryptanalysis of DES

给出了DES的两个较大的14轮线性逼近,它们的相关系数分别为最佳线性逼近相关系数的0.8倍和0.6倍,且涉及到完全相同的密钥和不同的明密文。结合这两个较好的线性逼近,提出了攻击DES的改进算法,利用改进后的算法可以在等量明密文对的情况下多得到9比特密钥值。

This paper proposes two linear approximations whose correlation coefficients are 0.8 times and 0.6 times of the best linear approximation＇s respectively.They involve the same key-bits and different cipher texts or plaintexts.By using the two linear approximations,this paper proposes an improved algorithm to attack DES,and another 9 key-bits can be attained under the same number of cipher-plaintexts.