Novel approach to image encryption: Using a combination of JEX encoding–decoding with the modified AES algorithm

Abstract

Many research works have been conducted so as to design an efficient image encryption algorithm. In this paper, we propose an algorithm that combines the image space requirement with image encryption. The proposed encryption technique uses the JEX encoding–decoding in combination with the Modified AES algorithm for encryption. In JEX encoding, the image is divided in pixel blocks, and on each pixel block column–row permutations are performed resulting into the generation of a header file which is then added to the image file. The resultant image then passes through the remaining steps of basic JPEG compression. The JEX-coded image is then encrypted using the Modified AES encryption algorithm. The modification in AES algorithm is performed on the round key generation procedure wherein a circular shift and mirror operations are performed on the 128-bit cipher key matrix. On the decryption unit, the encrypted image is decrypted using the same key obtained from the Modified AES decryption algorithm which is then followed by the JPEG decompression. On the decoder unit, the JPEG decoder decodes the image file by extracting the information from the header and performing the inverse transformation operation to decode the coded image so as to recover the uncompressed image.