A new method of image encryption using image blocking and chaos mapping

Encryption is one of the most powerful tools that ensures information security in the field of communication and information technology. Image encryption is different from other encryptions. This difference is due to the inherent characteristics of the images. Recent attempts to encrypt images have been based on chaos. In this paper, a new chaos-based encryption algorithm for image encryption is presented. In the proposed method, instead of encryption one image in each step, four images are encrypted simultaneously. In this way, four standard images are combined and a single image of their combination is created. Simultaneous encoding of four images will cause to complicate the proposed encryption algorithm, increase security, and extend the amount of gray area per pixel. Finally, the resulting image is XORed with encryption key and the encrypted image is generated. Considering the combination of four images and their simultaneous encoding, as well as examining a large number of image evaluation criteria, specifically the information entropy, that has achieved a value equal to 7/9994 in our proposed algorithm, which is really close to the ideal value of 8, shows that the proposed algorithm performs appropriately.