Abstract: The advances in multimedia and networking technologies
have created opportunities for Internet pirates, who can easily
copy multimedia contents and illegally distribute them on the Internet,
thus violating the legal rights of content owners. This paper describes
how a simple and well-known watermarking procedure based on a
spread spectrum method and a watermark recovery by correlation can
be improved to effectively and adaptively protect MPEG-2 videos
distributed on the Internet. In fact, the procedure, in its simplest
form, is vulnerable to a variety of attacks. However, its security
and robustness have been increased, and its behavior has been
made adaptive with respect to the video terminals used to open
the videos and the network transactions carried out to deliver them
to buyers. In fact, such an adaptive behavior enables the proposed
procedure to efficiently embed watermarks, and this characteristic
makes the procedure well suited to be exploited in web contexts,
where watermarks usually generated from fingerprinting codes have
to be inserted into the distributed videos “on the fly", i.e. during the
purchase web transactions.
Abstract: In the last decade digital watermarking procedures have
become increasingly applied to implement the copyright protection
of multimedia digital contents distributed on the Internet. To this
end, it is worth noting that a lot of watermarking procedures
for images and videos proposed in literature are based on spread
spectrum techniques. However, some scepticism about the robustness
and security of such watermarking procedures has arisen because
of some documented attacks which claim to render the inserted
watermarks undetectable. On the other hand, web content providers
wish to exploit watermarking procedures characterized by flexible and
efficient implementations and which can be easily integrated in their
existing web services frameworks or platforms. This paper presents
how a simple spread spectrum watermarking procedure for MPEG-2
videos can be modified to be exploited in web contexts. To this end,
the proposed procedure has been made secure and robust against some
well-known and dangerous attacks. Furthermore, its basic scheme
has been optimized by making the insertion procedure adaptive with
respect to the terminals used to open the videos and the network transactions
carried out to deliver them to buyers. Finally, two different
implementations of the procedure have been developed: the former
is a high performance parallel implementation, whereas the latter is
a portable Java and XML based implementation. Thus, the paper
demonstrates that a simple spread spectrum watermarking procedure,
with limited and appropriate modifications to the embedding scheme,
can still represent a valid alternative to many other well-known and
more recent watermarking procedures proposed in literature.
Abstract: This paper presents a watermarking protocol able to
solve the well-known “customer-s right problem" and “unbinding
problem". In particular, the protocol has been purposely designed
to be adopted in a web context, where users wanting to buy digital
contents are usually neither provided with digital certificates issued
by certification authorities (CAs) nor able to autonomously perform
specific security actions. Furthermore, the protocol enables users to
keep their identities unexposed during web transactions as well as
allows guilty buyers, i.e. who are responsible distributors of illegal
replicas, to be unambiguously identified. Finally, the protocol has
been designed so that web content providers (CPs) can exploit
copyright protection services supplied by web service providers (SPs)
in a security context. Thus, CPs can take advantage of complex
services without having to directly implement them.