A cryptographic model for better information security

Abstract

In this study, a novel cryptographic model that uses coupled map lattice is proposed for securing image. It incorporates mixing based on randomly generated secret key, sub-keys based substitution, confusion algorithm and coupled map lattice based diffusion process to enrich the security, sensitivity and robustness of the model. The control parameters of coupled map lattice and initial condition of chaotic systems are deduced using externally generated random secret key of 280-bit length. To make the encryption process more dependent on confusion and more sensitive to the encryption key, pixels of a channel are XOR-ed with pixels of other channel with an intelligent mix of sub-keys. Finally, the diffusion model based on coupled map lattice, binds the pixels in a way such that a single-bit change is reflected into a large number of pixels in the cipher image. Resistance to various kinds of attacks like plain text, brute force and statistical attacks are the important features observed in the proposed cryptographic model. Several studies related to correlation coefficients, histogram, anti-noise attacks, plain text analysis, NPCR, key sensitivity, UACI and key space analysis were carried out and corresponding results are given in detail. The simulation results yield an average NPCR score to be about 99.63% and UACI value 33.46%. A number of analysis performed and mentioned here, suggests the proposed model a potential candidate for image encryption application.