PICTURE ENCRYPTION METHOD BY APPLYING COSINE-TRANSFORM-BASED CHAOTIC SYSTEM: A REVIEW PAPER

Abstract

Due to its properties such as unpredictability and initial state sensitivity, Chaos is recognized as a natural candidate for cryptography applications. Some chaos-based cryptosystems, however, have been shown to exhibit different security defects because their chaotic maps used do not have complex dynamic behaviors. This paper introduces a cosine-transform-based chaotic framework to solve this problem (CTBCS). The CTBCS can generate chaotic maps with complex dynamical behaviors using two chaotic maps as seed maps. For example, using the CTBCS, we create three chaotic maps and evaluate their chaos complexity. We further propose an image encryption scheme using one of the generated chaotic maps. To separate adjacent pixels, the encryption scheme uses high-efficiency scrambling and uses random order substitution to distribute a slight shift in the plain image to all cipher-image pixels. The performance appraisal shows that the chaotic maps generated by the CTBCS exhibit significantly more complex chaotic behaviours than the current ones