Abstract: Aiming at the problem of high false alarm error rate of the classical SVD domain digital image watermarking algorithm， proposes a digital image watermarking algorithm based on IWT and SVD.Firstly， the algorithm performs 1 level of IWT decomposition on the copyright image to obtain 4 subbands， then performs the SVD transform to the 4 sub-bands. Secondly， it embeds the watermark image information directly into the singular values of the 4 sub-bands of the copyright image. It also proposes a digital signature authentication mechanism in the watermark embedding process to encrypte the watermarked image with the digital signature while processing the watermark embedding. Finally， before the watermark image being extracted， the digital signature is verified to avoid the problem of false alarm error. Experiments show that， this algorithm has good visuality and robustness to resist attacks.

Key words: IWT, SVD, digital signature, watermark, false alarm error