Applications of cellular automata in digital watermarking processes

Los grandes avances de la tecnología hoy en día han ayudado a la comunicación y distribución de todo tipo de material digital de manera instantánea. Este es uno de los grandes beneficios de las tecnologías de la información y comunicación, donde también existen diversas amenazas de infracciones relacionadas al derecho de autor o Copyright, falsificaciones de contenido, plagios, por mencionar algunas. Al pasar de los años se han desarrollado diferentes algoritmos computacionales para coadyuvar a la protección de datos en archivos de textos, audio y video, respectivamente. En este artículo se presenta un análisis del estado del arte sobre el uso de autómatas celulares dentro del campo de procesamiento de imágenes digitales en conjunto con la técnica de Marcado de Agua Digital (Digital Watermarking).The great advances in technology today have helped the communication and distribution of all kinds of digital material information instantly. This is one of the great benefits of information and communication technologies, where there are also various threats of infringements, violations related to copyright, falsification of content, and plagiarism, to name a few, etc. Over the years, different computational algorithms and methods have been developed to help protect data in texts, audios and videos files, respectively. In this article, an analysis of the state of the art on the use of cellular automata within the field of digital image processing is presented in conjunction with the technique of, such as the use Digital Watermark algorithm  etc

A novel robust watermarking algorithm for encrypted medical image based on DTCWT-DCT and chaotic map

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