Abstract: To improve the performance of images tamper detection and recovery, an authentication watermarking scheme based on block features and chaotic sequence was presented. For each block of size 2×2 pixels,discrete cosine transform(DCT)coefficients were used to generate watermarking and embedded into the two least significant bits of its mapping block which was determined by chaotic sequence. The conventional authentication methods were improved by combining parity detection and the tampered region could be self-recovered by extracting characteristic information of the valid block. Experimental results demonstrated that the proposed method not only improved the quality and security of watermarked images, but also could detect tampered regions accurately and reconstruct images while keeping the recognition quality. Additionally, the scheme was not vulnerable to the content-only attack.

Key words: image authentication, tamper detection, digital watermarking, self-recovery, chaos