JPEG Image Encryption Algorithm Based on Spatiotemporal Chaos

Recently, various image encryption algorithms have been proposed in order to images from unauthorized access and distribution, and most of them only has the operation on encryption in spatial domain, but no consideration of its corresponding compression. Therefore, to ensure the level of compression ratio and image quality, a class of JPEG image encryption algorithm based on spatiotemporal chaos is proposed in this paper. Here, only the DC coefficients are extracted and split so that general statistical distribution of all Discrete Cosine Transform (DCT) coefficients remains unchanged. For the encryption process, a spatiotemporal-chaos system is utilized to shuffle the DCT blocks and diffuse the quantized DC coefficients. Analysis and experimental results show the encryption algorithm is secure and the compression ration is good.