A blind JPEG image watermarking in the DCT domain

A blind, low complex, fast, and highly resistant to attacks watermarking algorithm is proposed for JPEG compressed images. Our method is a discrete cosine transform (DCT) and block based algorithm that adds some Huffman code words to the end of the code sequence of some blocks during JPEG compression procedure. Via a blind approach in decoder, each block is determined to be a watermarked or unwatermarked one. While the robustness to attacks is still preserved, the size of watermarked image may differ from the JPEG compressed one insignificantly. Presented scheme is used for pictures that have perceptually high quality and due to this, are very apt to watermarking task for the sake of contents owner authenticity. Peak signal to noise ratio (PSNR) will be our benchmark to asses the quality of images.