In early days, informations are shared in the form of textmessages. To secure those messages from unauthorized personAES and DES algorithm are used for hiding the information.Later, due to the development of technologies peoples startsto sending the information in the form of images. In order tosecure the images from hackers and unknown person becomea serious challenge in this digital world. AES and DESalgorithm are not suited for multimedia information due tosome characteristics like high data and high correlation amongthe pixels. Those two algorithms are typically designed for thepurpose of textual information.
1-3 Encryption is a efficientmethod to solve these issues. Encryption is a process whichuses finite set of instruction called an algorithm to convertoriginal image to an encrypted form. A chaotic system is richin significance and in implication because of ergodicity andpseudorandom sequences. These structures are too complexand difficult to analyze . one round of permutation andsubstitution are done to get the accurate result. Here, thepermutation and substitution are done by row by row / columnby column instead of pixels by pixels in order to increasethe speed of encryption4.Wang Xing-Yuan at5 presenteda image encryption based on chaotic system and cycle shift.
Cycle shift is a suitable for scrambling the images and canalso change the values in image pixels. It has large key space,high level security encryption scheme and resistive againstknown attacks. In6Based on RCA combining chaos , Inconfusion step,each pixel of image is divided into units of4 bits to permute for permutation.
Logistic map is used forgenerating the keys and 2D RCA is used to achieve the bitlevel at diffusion stage. It belongs to the symmetric system.Enayatifar at al7 Advanced their work by using tinker bellchaotic map, DNA sequence and CA simultaneously. Here CAis used to generate pseudorandom numbers . For encryptionchaotic map is combined with Tinkerbell chaotic mapping.
Wang Leyuan8 proposed a color image encryption based ontwo complex chaotic system. The main purpose of this paperis to mix RGB channel by using pseudorandom numbers . So,in confusion step pixels are modified by using 2D process andone step process.
The mix of RGB channel leads to multilevelencryption.