A method to fabricate encrypted Fourier transform holographs is provided. With optical system or computer, the original digital image is modulated by double random phase plates and interferes with the reference light, and then the encrypted Fourier transform holograph is created, which can be regarded as the watermark and hidden in a host image to guarantee the copyright authentication. The printing and scanning experiments prove that the digital images with watermark can be printed on the certificates with ordinary printing technology. The digital images with watermark can be scanned and input into the computer, and the digital watermark can be extracted with blind detection technology. The credibility of the printed matter is proved, and the anti-fake performance is improved.