This paper presents a digital image encryption algorithm based on four-value chaotic array. It uses chaotic maps to generate a four-value chaotic array whose size is as big as the image. In encryption processing

we deal with the different value in the chaotic array separately

and use different keys to encrypt pixels which correspond to different chaotic array value respectively and then put the result to the appropriate position in the chaotic array according to the given random integers. Decryption is the converse of encryption. The analysis and the results of experiments show that the scheme has low time complexity

low space complexity and good security.