An image encryption method based on tent and Lorenz chaotic systems

In view of the shortcomings of traditional image encryption schemes, image encryption methods based on chaos theory has come into being. This paper presents a grayscale image encryption method using the combination of Tent and Lorenz chaotic maps. It leverages the Lorenz sequence to alter the Tent sequence in order to improve the randomness of secret keys. It also couples generated keys with plaintext and ciphertext during encryption to effectively defend against the plaintext attack. We have implemented the proposed method in Matlab, and evaluated it in several experiments. According to the NIST statistical tests, avalanche effect, and parameter analysis, secret keys produced by this method have good randomness and the key space is larger than 256 bits. Histograms and correlation tests of images encrypted by this method reveal the encryption achieves good confidentiality.