A new chaotic fragile watermarking algorithm is presented.With the high sensitivity on initial value of the chaotic mapping and the block-wise independent technology

the image DCT sub-high coefficients and a watermarking key are combined as the initial value of logistic maps for the generation of the watermarks

then the watermarks are embedded into the DCT high coefficients to get watermarked image.The watermarks can be blindly extracted according to the DCT coefficients.Experimental results show that the algorithm can detect any modification to the watermarked image and localize the tampers on the watermarked image.