On the security of a class of image encryption schemes

— Recently four chaos-based image encryption schemes were proposed. Essentially, the four schemes can be classified into one class, which is composed of two basic parts: permutation of position and diffusion of pixel value with the same cipher-text feedback function. The operations involved in the two basic parts are determined by a pseudo random number sequence (PRNS) generated from iterating a chaotic dynamic system. According to the security requirement, the two basic parts are performed alternatively for some rounds. Although the designers claimed that the schemes are of high quality, we found the following security problems: 1) the schemes are not sensitive to the changes of plain-images; 2) the schemes are not sensitive to the changes of the key streams generated by any secret key; 3) there exists a serious flaw of the diffusion function; 4) the schemes can be broken with no more than logL(MN) +3 chosen-images when the iteration number is equal to one, where MN is the size of...

• Type: Conference
• Year: 2008
• Where: ISCAS
• Authors: Chengqing Li, Guanrong Chen
• Keywords: Basic Parts, Hardware, Image Encryption Schemes, ISCAS 2008, Pixel Values