A Watermark Algorithm for Image Content Authentication and Correcting Errors in Terms of Pixels

This paper proposes a watermark algorithm for image content authentication and correcting errors in terms of pixels. There are two characteristics: first, aiming at defects of poor safety and the complicated calculation which are exiting in image encryption algorithm based on chaotic sequences, a new image chaotic encryption algorithm based on sampling without replacement is put forward. Second, the application of combination mapping technique supplies a gap which is exiting in image content authentication watermark. Using the authentication, digital image can be corrected in terms of pixels, and with the minimum embedded capacity and the maximum SNR. The image is divided into blocks by 8×8, image content authentication and correcting errors is done on blocks. In the scheme, chaotic encryption not only ensures the safety, but also advances correcting rate.