A research on the medical image authentication watermark method based on chaos

Aiming at safety problems in the storage and transmission process of medical images, this paper puts forward a completely fragile watermark algorithm based on chaos for the authentication of the integrity of medical images and tamper localization. The algorithm utilizes original medical image blocks and calculates gray average image sub-blocks as image characteristic watermarks. In addition, it uses chaos technology to encrypt watermarks, determines the position of each embedded watermark bit and embeds the watermark in the least significant bit of each pixel of medical images. The experimental results show that the method not only is appropriate for the authentication of medical images but also has high and stable Signal to Noise Ratio (SNR), strong sensibility to tamper as well as high tamper positional accuracy and safety.