A multiparty watermarking protocol for cloud environments

The advances in multimedia and networking technologies together with the wide spread of social networks and user generated content platforms have turned ordinary web users into actual multimedia content generators. This has given rise to the copyright protection problem of multimedia contents published or distributed on the Internet. In fact, dishonest web users or administrators of networks and platforms can easily duplicate the digital images and videos they host without reducing their perceptual quality. Then, such contents can be maliciously modified and/or re-distributed, thus damaging the reputation of their legitimate owners, or revealing their private information, or causing economic loss. A possible solution to such a problem consists in protecting digital content by adopting mechanisms of copyright identification and content tracking by fingerprinting based on digital watermarking technologies used in conjunction with watermarking protocols. However, most of the watermarking protocols documented in the literature have been designed as two-party protocols between classic buyers and sellers. On the contrary, the complexity of the distribution models of digital contents on the Internet needs new watermarking protocols based on multi-party approaches, which should make it possible to securely involve actors different from buyers and sellers, such as, for example, cloud computing operators. The paper presents a multi-party watermarking protocol that enables content owners to exploit cloud computing environments to protect the digital contents that they want to publish or distribute on the Internet. Such a result is achieved by enabling the different actors involved in the online transactions needed to support web content protection and distribution to securely interact according to a protocol that can mediate among conflicting interests.