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A Novel Robust Watermarking Algorithm for Encrypted Medical Image Based on DTCWT-DCT and Chaotic Map

Jing Liu1,5, Jingbing Li1,*, Jieren Cheng1, Jixin Ma2, Naveed Sadiq3, Baoru Han4, Qiang Geng5, Yang Ai5
College of Information Science and Technology, Hainan University, Haikou, 570228, China.
School of Computing and Mathematical Sciences, Faculty of Liberal Arts and Sciences, University of Greenwich, Greenwich, London, SE10 9LS, UK.
Ocean College, Zhejiang University, Hangzhou, 310058, China.
College of Medical Informatics, Chongqing Medical University, Chongqing, 400016, China.
Faculty of Network Science, Haikou University of Economics, Haikou, 571127, China.
*Corresponding Author: Jingbing Li. Email: ; .

Computers, Materials & Continua 2019, 61(2), 889-910.


In order to solve the problem of patient information security protection in medical images, whilst also taking into consideration the unchangeable particularity of medical images to the lesion area and the need for medical images themselves to be protected, a novel robust watermarking algorithm for encrypted medical images based on dual-tree complex wavelet transform and discrete cosine transform (DTCWT-DCT) and chaotic map is proposed in this paper. First, DTCWT-DCT transformation was performed on medical images, and dot product was per-formed in relation to the transformation matrix and logistic map. Inverse transformation was undertaken to obtain encrypted medical images. Then, in the low-frequency part of the DTCWT-DCT transformation coefficient of the encrypted medical image, a set of 32 bits visual feature vectors that can effectively resist geometric attacks are found to be the feature vector of the encrypted medical image by using perceptual hashing. After that, different logistic initial values and growth parameters were set to encrypt the watermark, and zero-watermark technology was used to embed and extract the encrypted medical images by combining cryptography and third-party concepts. The proposed watermarking algorithm does not change the region of interest of medical images thus it does not affect the judgment of doctors. Additionally, the security of the algorithm is enhanced by using chaotic mapping, which is sensitive to the initial value in order to encrypt the medical image and the watermark. The simulation results show that the pro-posed algorithm has good homomorphism, which can not only protect the original medical image and the watermark information, but can also embed and extract the watermark directly in the encrypted image, eliminating the potential risk of decrypting the embedded watermark and extracting watermark. Compared with the recent related research, the proposed algorithm solves the contradiction between robustness and invisibility of the watermarking algorithm for encrypted medical images, and it has good results against both conventional attacks and geometric attacks. Under geometric attacks in particular, the proposed algorithm performs much better than existing algorithms.


Encrypted medical images, zero-watermarking, DTCWT, perceptual hash, chaotic map

Cite This Article

J. Liu, J. Li, J. Cheng, J. Ma, N. Sadiq et al., "A novel robust watermarking algorithm for encrypted medical image based on dtcwt-dct and chaotic map," Computers, Materials & Continua, vol. 61, no.2, pp. 889–910, 2019.


This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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