Image Encryption and Analysis using Dynamic AES

Abstract

AES (Advanced Encryption Algorithm) is a block cipher, which is world wide implemented for encryption of data. It has been accepted as a standard for data security since 2001. AES is a substitution and permutation cipher, which provides confusion by using substitution box (S-Box) in the algorithm. The main drawback of AES is that it uses static S-Box throughout algorithm, which compromise the security of AES and may be exposed to different algebraic attacks. So to overcome this problem new Dynamic AES algorithm developed by key dependent dynamic S-Box using dynamic irreducible polynomial and affine constant. The analysis is done on gray scale and colour images. Both the images are encrypted and decrypted by using standard AES and Dynamic AES. Quality of algorithm and the level of security is analyzed based on the parameters like Image Histogram Analysis, Adjacent Pixel Correlation Analysis, Image Entropy, Number of Pixels Change Rate (NPCR), Unified Average Changing Intensity (UACI), Encryption Quality.