基于序列密码的图像加密算法

Image Encryption Algorithm Based on Sequence Cipher

结合序列密码和混沌映射的优点,提出了一种灰度图像的加密算法.该算法首先将图像矩阵化,然后通过线性移位寄存器生成周期序列,通过序列的性质选出序列中的一段并且根据序列段生成密钥矩阵,因为密钥是通过序列流产生的,所以和明文流与密文流无关,能够有效地抵御选择明文攻击;已知明文攻击等攻击手段.然后通过Hill密码加密原理使用密钥流对图像矩阵进行加密,对加密后的矩阵进行置乱迭代后生成密文图像.经过理论分析和实验验证,该算法具有敏感性高,抗差分攻击能力强,信息熵高等优点.

In this paper,a gray image encryption algorithm is proposed by combining the advantages of sequence cipher and chaotic mapping.Firstly,the image is converted into a matrix,and then the periodic sequence is generated by linear shift register.According to the nature of the sequence,a segment of the sequence is selected,and the key matrix is generated according to the sequence segment.As the key is generated by sequence stream,it has nothing to do with plaintext stream and ciphertext stream,and can effectively resist chosen plaintext attack and known plaintext attack.Then,the image matrix is encrypted by using key stream based on Hill cipher.The encrypted matrix is scrambled and iterated to generate a ciphertext image.Through theoretical analysis and experimental verification,the algorithm has the advantages of high sensitivity,strong anti-differential cryptanalysis ability and high information entropy.