JPEG Encryption with DC Prediction and Run-Based RS Pairs Permutation

JPEG image encryption technology converts original images into noise-like images that do not contain any useful information, ensuring the security and privacy of valuable images. At present, most existing work may not achieve a good balance between file size preservation and security. Therefore, in order to solve this issue, we present a new JPEG image encryption scheme. In our scheme, we first perform predictions on the DC coefficients, and then implement averaging operation on the prediction error, which provides security effects while effectively decreases the encoding length. To further strengthen the diffusion performance, block permutation excluding the DC coefficients is executed. In addition, in order to control the file size growth, AC coefficients are protected by the run-based RS (run/size) pairs permutation. The experimental results show that the proposed scheme can not only effectively preserve the image file size, but also offers satisfactory security.