José Antonio Álvarez-Bermejo

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In this paper we propose a new protocol to manage multicast key distribution. The protocol is based on the use of orthogonal systems in vector spaces. The main advantage in comparison to other existing multicast key management protocols is that the length and the number of the messages which have to be sent are considerably smaller. This makes the protocol(More)
In this work, we introduce algorithms to speedup and to scale a classical secure multicast protocol that currently goes unused due to its computational and data management requirements when the audience becomes large. This is in spite of its agreeable cryptographic properties, which offers real applicability. A core component of such an algorithm is the(More)
We introduce a hierarchical approach for secure multicast where rekeying of groups of users is made through a method based on Euclid’s algorithm for computing GCD. We consider tree arrangements of users that decrease requirements on bandwidth as protocols of the same nature, but also show that computational requirements are less than in other similar(More)
Media distribution over the Internet is a fact. Finding a way to protect content streaming is a hot topic. This paper presents both a new and efficient key multicasting protocol based on the use of orthogonal systems in vector spaces, and its scalable implementation by means of a platform independent server. The protocol outstands in exchanging a small(More)
This paper presents a method and its implementation, built on the blind signatures protocol, to trace users sharing their licenses illegally when accessing services provided through Internet (Web services, Streaming, etc). The method devised is able to identify the legitimate user from those users who are illegally accessing services with a shared key. This(More)