A new Grayscale image encryption algorithm composed of logistic mapping, Arnold cat, and image blocking.

This paper proposes a new chaotic-based encryption algorithm to encrypt images securely and effectively. A combination of Arnold cat, logistic mapping and image blocking has been used to design this algorithm. The proposed algorithm is a special algorithm that not only does it use image blocking once to relocate the pixels in four areas of the image separately but also uses an Arnold cat mapping to relocate the pixels across the whole image once again. This results in a higher number of pixel relocations which makes it impossible to decode without the key. The other interesting and new point is the particular use of chaotic logistic mapping to develop three image keys and to combine them with the input image, and to develop four other image keys to encrypt the image. Relocation of the input image blocks and the images generated by the logistic mapping are conducted through sorting the numbers generated by the mapping and how they have been relocated. Then, Arnold cat is used to relocate the pixels across the whole image (which is a combination of the input image and three images generated by logistic mapping). Eventually, the encryption operation is conducted on the obtained image using the encryption key (the image generated through the combination of the four keys). Numerous statistical tests and security analyses indicate the excellent security of our proposed algorithm. [ABSTRACT FROM AUTHOR]