Logistic Map and Contourlet-Based Robust Zero Watermark for Medical Images

Abstract

Aiming at malicious tampering and privacy protection of medical data during transmission and storage, we proposed a logistic map and contourlet transform robust zero watermark for encrypted medical images. We selected meaningful binary images as embedded watermarking. First, the original image was encrypted by using chaotic logistic sequence, and then that image was encrypted by contourlet two-level transform, the obtained low-frequency subband was constructed feature sequence after DCT transform. We used zero-watermark technology to associate the watermarking with the feature sequence, and the watermarking was embedded and extracted in the encrypted image. Our experimental results show that the proposed algorithm has good robustness against common and geometric attacks. The original image was not changed during the embedding and extraction of the watermarking. Because encrypted images and watermarking were both in encrypted domain, the embedding and extraction of watermarking can be done by a third party to improve image information security.