Abstract:Blind watermarking plays a significant role in copyright protection and information hiding. To enhance the security of watermark image information, a dual encryption method is proposed, which combines block shuffling with logistic chaos encryption using two sets of random numbers as keys. This dual encryption technique is applied to blind wa-termark images, utilizing a combination of discrete wavelet transform (DWT) and discrete cosine transform (DCT) as the embedding method. First, the watermark image is divided into small blocks, which are shuffled and rearranged using one set of random numbers as the key, while recording the shuffling sequence of block positions. Subsequently, the shuffled blocks are reassembled into an image, and another set of random numbers is used as the key for logistic chaos encryption, rendering the watermark image chaotically invisible. Then, a double discrete wavelet transform (DWT) is applied to the carrier image, followed by a discrete cosine transform (DCT), allowing the encrypted water-mark image to be embedded. This achieves the concealment of the blind watermark. Experimental results demonstrate that this method exhibits robustness, excellent invisibility, and secrecy.