To design a securer and easier constructed watermark

the biorthogonal integer wavelets with parameter based on lifting scheme is constructed

and a Hash function is built by transmutative Rijndael code. A digital watermark is designed by integer wavelets with parameter combined with RH arithmetic operators. This watermark algorithm posed is a kind of weak algorithm. Without original image and standard watermark

it is shown to be most sensitive to distortion

that is even 1 bit of change to the picture can be sensed. And furthermore the region distorted can be easily oriented in this algorithm. Compared with the traditional digital watermark based on integer wavelets

the integer wavelets with parameter can reduce operation and increase security by changing the parameter. The integer wavelets with parameter not only simplify the calculation but also improve the security of the watermark. And the transmutative Rijndael code increases the availability ratio of code and circuit

which reduces the cost of hardware realization greatly. Lots of simulation results show that the weak watermark is sensitive to the distortion of the image. When the parameter in the wavelet is wrong

the watermark cannot be detected correctly. The weak watermark method presented in this paper has wide applications.