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 paper we use the Diffie–Hellman key exchange protocol to introduce a decentralized key agreement protocol based on elliptic curves. We do not use any public key infrastructure, which makes it suitable for light devices with low computational and storage capabilities. Thus mobile devices can directly authorize other mobile devices to exchange keys in(More)
Prevention and detection of bullying due to racial stigma was studied in school contexts using a system designed following "gamification" principles and integrating less usual elements, such as social interaction, augmented reality and cell phones in educational scenarios. "Grounded Theory" and "User Centered Design" were employed to explore coexistence(More)
As first year students come from diverse backgrounds, basic skills should be accessible to everyone as soon as possible. Transferring such skills to these students is challenging, especially in highly technical courses. Ensuring that essential knowledge is acquired quickly promotes the student's self-esteem and may positively influence failure rates.(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)