A fragile watermark is designed using integral wavelet transform combined with hash function in order to verify the integrity of medical images. Even 1 bit of change in the picture can be sensed. Furthermore the region distorted can be easily oriented in this algorithm without an original image. Compared with the traditional digital watermark based on wavelet transform

the integer wavelets not only simplify the calculation but also improve the quality of watermarked image. And the hash function constructed with MD5 algorithm increases the security and ability of tamper localization of watermark. The results of experiment indicates that watermark scheme is highly sensitive to the distortion of the image. Since it requires a key during both the insertion and the extraction procedures

it has high security and the whole process is simple and accurate.