An approach using stream cipher algorithm for image encryption and decryption

This paper treats the protection of images. We are dealing with the problem of image encryption and decryption. The encryption scheme is done by using the stream cipher system based on the nonlinear combination generator. The proposed keystream generator consists of fourteen binary primitive nonlinear feedback shift registers (NLFSRs) and one Boolean function. The Boolean function combines the output sequences of the fourteen NLFSRs to produce the keystream. All feedback shift registers employed in the keystream generator are primitive and nonlinear. The proposed encryption scheme is simple and highly efficient. Security analysis covers key sensitivity analysis, key space analysis, correlation coefficient analysis, noise analysis, statistical attacks, Berlekamp-Massey attack, correlation attack and algebraic attack. Based on experiment results and the security analysis it can be concluded that the proposed encryption scheme is highly key sensitive, highly resistance to the noises and shows a good resistance against brute-force, statistical attacks, Berlekamp-Massey attack, correlation attack and algebraic attack.