A Parallel Bit-Plane Operation Based Chaotic Image Encryption Scheme

Nowadays, the Internet is the medium through which peoples are sharing digital images. However, security is an issue in sharing of those digital images. So the main objective is to provide security in digital images. This paper proposes a bit-plane operation based encryption schemewhich to provide security in digital images. In this encryption scheme, first, the bits in bit-planes are confused by using 4D-hyperchaotic map and then diffused by using PWLCM (Piecewise Linear Chaotic Map) system. Both the confusion and diffusion operations are performed in parallel and independent to get better security in images. The main advantage of this scheme is the use of separate chaotic sequences and separate key images to perform parallel and independent bit-level operation. This type of parallel and independent operation confuses pixels, reduces in attacking the cryptosystem by attackers, and thus increases the level of security. Moreover, the use of 4-D hyper-chaotic map increases the key space of the algorithm and thus more resists the algorithm against brute-force attack. Apart from that, a "Secure Hash Algorithm SHA-256" is used in this scheme to generate the secret keys which to provide resistivity against "Known-Plaintext Attack (KPA)" and "Chosen-Plaintext Attack (CPA)". The proposed method has better performance in terms of encryption efficiency, security, and resistivity for most of the common attacks.