An image encryption algorithm based on DNA random encoding combined with chaotic mapping is proposed.In order to solve the problem that the algorithm using single encoding mode to encrypt image is vulnerable to chosen-plaintext attack

the chaotic sequence generated by logistic chaos mapping controls the random DNA coding of the pixel values of the image.The initial value of the Lorenz chaotic mapping is generated by using SHA-384 and plain-image.The scrambling part uses combination of row-column scrambling and cross scrambling.The diffusion part uses grouping structure to complete the diffusion of pixel values.Then the encrypted image is tested for security analysis.Using the 256×256×3 Lena color image for test

the correlation coefficients of the adjacent pixels of the encrypted-image are close to 0

and the information entropy is greater than 7.997

which is close to the theoretical value of 8.The experimental results show that the proposed algorithm enhances the security of the cipher-text

increases size of key space and resists various attack modes.