Modified Advanced Encryption Standard For Text And Images

Security of multimedia data is an imperative issue because of fast evolution of digital data exchanges over unsecured network. Multimedia data security is achieved by methods of cryptography, which deals with encryption of data. Standard symmetric encryption algorithms provide better security for the multimedia data. But applying symmetric key encryption algorithm on more complex multimedia data (mostly images); we might face the problem of computational overhead. To overcome that problem, we analyze the Advanced Encryption Standard (AES) and modify it, to reduce the calculation of algorithm and for improving the encryption performance. In modified AES algorithm instead of using Mixcolumn we use the permutation step, taking from Data Encryption Standard (DES) algorithm. Theoretical analysis and experimental results prove that this technique provides high speed as well as fewer overheads on data. Modified-AES algorithm is a fast lightweight encryption algorithm for security of multimedia data. All above advantages make algorithm highly suitable for the images and plaintext transfer as well, than the AES algorithm.