Information hiding based on quantization index modulation (jitter) courses do watermark embedding and extraction, the content is as follows: 1. The airspace of embedding and extraction (black and white picture) 2. Include changes in DCT and quantization watermark embedding and extraction (color chart) 3. 6 kinds of attack test (gaussian noise, enlarge attacks, cutting, translation, pixel value changes, rotation) 4. PSNR calculation 5. Explore quantitative table changes.