Abstract: Encryption basically follow two different approaches, the first being encrypting the images through encryption algorithms using keys, the other approach involves dividing the image into random shares to maintain the images secrecy. Chaotic encryption of images is the better approach for cryptography. The chaotic encryption algorithms have several advantages over the traditional encryption algorithms like high security, speed, sensible computational overheads and computational power. The Chaos theory  that  aims to disadvantage of existing algorithm In recent years, a large type of cryptanalytic algorithms supported chaos are argue and most of them are verified to achieve success by adopting the normal permutation-diffusion design. However, one downside these strategies largely hold is that they need very little reference to the plaintext or, to be precise, the link between them is quite less. The downside makes the encoding algorithms prone to the known-plaintext and chosen-plaintext attack. In addition, the secret keys are unit stationary at the most times, and that they can’t be elite dynamically by the corresponding plain image pixels. So as to beat these disadvantages mentioned higher than, we have a tendency to introduce a new chaos-based image encoding rule with dynamic key choice mechanisms. During this we have a tendency to gift a dynamic keystream sequence cluster choice mechanism (DKSGSM) and a dynamic keystream choice mechanism (DKSM). They powerfully enhance the connection between the plaintext and also the encryption scheme. Especially, the DKSGSM and DKSM expand the choice vary of the keys and permit us to pick out the keys dynamically by the corresponding plaintext pixels. What’s a lot of, by adopting the bidirectional  encryption, we are able to unfold the influence to the complete image once a little modification in plain image and this could greatly increase the protection level of our encryption technique.

keywords: Dynamic keystream sequence group selection mechanism(DKSGSM),Dynamic keystream selection mechanism(DKSM),ImageEncryption,Chaos,Permutatio, Diffusion.