Enhancing digital image integrity by exploiting JPEG bitstream attributes

The need for protecting a huge amount of digital images on the internet has become an important requirement against different kind of attacks in order to insure transmitted process in a secure way. Cryptography introduces many security goals to achieve privacy of image include confidentiality, authentication and integrity. Encryption process may applied on the result of JPEG DCT-based encoding process, which are DC and AC coefficients, where DC coefficients present the average of the overall magnitude of the input image and AC coefficients present the higher frequency components of image. In this paper, we develop a new model for securing the transmitted images via wireless network by parsing JPEG bitstream to encrypting both DC and AC coefficients in each 8×8 block of image. This work utilizes the features of DCT-based encoding process preserving low complexity, efficient compression, and robustness to protect the image integrity. The experiments result shows that the proposed approach gives an interesting and a significant robustness ratio reaching a range of 60.3 dB for Peak Signal-to-Noise Ratio (PSNR) and a 0.006% for Bit Error Rate (BER) in average. The obtained results are discussed in details.