# Multimedia content protection: from data hiding to encryption, through obscuration and secret sharing _by William Puech (LIRMM | Université de Montpellier) - 2025.11.20_ ###### tags: `VAADER` `Seminar` ![2025_Seminaire_W_PUECH](https://hackmd.io/_uploads/rkxB_FuJWx.png) ## Abstract More and more multimedia data, such as images, videos and 3D content, are transmitted over digital networks, stored or shared in the Cloud, and shared and visualized on social networks. In addition to the need to compress this multimedia data, which is very voluminous, for reasons of confidentiality, privacy or secret information, it is increasingly necessary to protect multimedia content directly, and not only the access to networks. In this tutorial, after detailing the specifics of each type of multimedia data, both in terms of compression and protection, we will present the various possible facets for protecting this multimedia content and illustrate with different applications from medical imaging to the Metaverse, passing through the manufacturing industry for fashion and videos from drones. The first part will be dedicated to data hiding, in order to differentiate between watermarking and steganography, and will finish with a discussion of steganalysis. The second part will detail the cryptographic aspects applied to multimedia content, distinguishing selective encryption from partial encryption, and concluding with crypto-compression (image, video and 3D object). The third part will present different methods of image darkening, reversible or not, visible or not. We will see that non-visible image obscuration relies mainly on the generation of false images. And finally, methods for sharing secrets applied to images will be discussed. Then we will end on a discussion of the cat and mouse game, to highlight the adversarial attacks and defenses that need to be taken into account.