Abstract: “In the paper, a chaotic key-based algorithm (CKBA) for image encryption methodology is proposed, which is a value substitution cipher. This paper estimates its security and points out that known-plaintext and chosen-plaintext attacks can break it with only one known plain-image making it highly secure and brute force attacks cannot break it. In addition, its security to brute-force attack is very high due to the stochastic behavior occurring in a deterministic system. So this key is secure atall from the strongly cryptographic viewpoints. Lorentz attractors are heavily dependent on initial condition and have the lowest level of predictability lead to use fullness in the encryption of any form of information either image or text.Encryption based on Lorenz strange attractor has been studied and applied.”

Keywords: chaotic systems, stochastic, cryptography, stream