Improvised block cipher customized for multimedia security

The paper proposes an improved, modified version of block cipher PRESENT to make it suitable for use in multimedia applications. For encrypting multimedia one of the core requirements is that the scheme should be computationally less expensive so as to sustain the bulkiness attributed to multimedia. Though, PRESENT is a very lightweight block cipher and is found efficient for textual content yet it is not directly suitable for multimedia. This is because of its block-size limitation which limits the diffusion of redundancy within the block of plaintext encrypted. Hence, if the redundancy extends beyond the block size, the same redundancy gets reflected in the cipher and this is a situation which is practically present in all forms of multimedia. Thus, an attempt is made to overcome this limitation by introducing chaos within the operations performed during encryption. And along with this, focus is kept that the overall computational expense of the improved scheme is not increased much.