中文摘要：

对一类选择性加密方案的安全性进行了分析,并根据图像相邻像素相关性的性质,利用密文中泄露的信息和已知明文攻击方法,给出了针对此类加密方案的攻击方案.通过实验验证了攻击方案的有效性.实验结果表明,对于相邻像素相关度较高的图像,利用密文中未加密的信息可以用较少的明文恢复出较多的明文信息,说明了此类选择性加密方案对于相邻像素相关度较高的图像是不安全的.最后,针对已知明文攻击,对选择性加密方案提出了改进意见.

英文摘要：

The security of a class of selective encryption scheme was analyzed.According to the characteristics of the correlation of adjacent image pixels,an algorithm to attack the encryption scheme was given using the disclosed information from cipher text and the method of known-plaintext attack,and the validity of the algorithm was verified by experiments.The experimental results showed that the higher the correlation of adjacent pixels of an image,the less the plaintext available to recover more information in plaintext by use of not encrypted information in cipher text.Therefore,for an image which has a high correlation between adjacent pixels,the selective encryption scheme is unsecured.The selective encryption scheme is thus correspondingly.