Although digital watermarking can be considered one of the key technologies to implement the copyright protection of digital contents distributed on the Internet, most of the content distribution models based on watermarking protocols proposed in literature have been purposely designed for fixed networks and cannot be easily adapted to mobile networks. On the contrary, the use of mobile devices currently enables new types of services and business models, and this makes the development of new content distribution models for mobile environments strategic in the current scenario of the Internet. This paper presents and discusses a distribution model of watermarked digital contents for such environments able to achieve a trade-off between the needs of efficiency and security.
The advances in multimedia and networking technologies have created opportunities for Internet pirates, who can copy digital contents and illegally distribute them, thus violating the legal rights of content owners. In such a situation, digital watermarking has gained popularity as a main technology to implement the copyright protection of multimedia digital contents distributed on the Internet. We present a novel "nonblind" watermarking procedure for JPEG images based on the use of protected extensible markup language (XML) documents. The procedure enables the copyright owner to insert a distinct watermark code identifying the buyer into the distributed images. Furthermore, to increase the security and robustness levels of the procedure, the watermark is repeatedly embedded into an image in the discrete cosine transform (DCT) domain at different frequencies and by exploiting both block classification techniques and perceptual analysis. The embedded watermark is then extracted from an image according to the information contained in a protected XML document that is associated to the image.
This paper presents and discusses a web oriented, interactive anonymous buyer-seller watermarking protocol. In particular, the protocol enables buyers who are neither provided with digital certificates issued by trusted certification authorities (CAs) nor able to autonomously perform security actions to purchase digital contents distributed by web content providers (CPs) while keeping their identities unexposed during web transactions. The protocol also allows guilty buyers, i.e. who are responsible distributors of illegal replicas, to be unambiguously identified. Finally, the protocol has been designed so that CPs can exploit copyright protection services supplied by web service providers (SPs) in a security context. Thus, CPs can take advantage of complex protection services without having to implement them.