2009
Díaz-Sánchez, D., A. Marín, F. Almenárez, and A. Cortés. "Sharing conditional access
modules through the home network for Pay TV Access." Journal/Magazine: Transactions
on Consummer Electronics (Accepted, Pending to be published) (2009).
Abstract
: In this article we present a system for sharing a Conditional Access
Module among different visualization devices. Current pay-TV systems require having
conditional access modules and smart cards replicated at every visualization device
willing to access Pay-TV contents. In this article, we show how a home gateway,
capable of securely distribute decryption keys to home visualization device, an
inexpensive descrambler, and a home network, enable a flexible solution to access
Pay-TV.
2008
Cortés-Martín, A., C. García-Rubio, C. Campo, A. Marín López, F. Almenárez Mendoza,
and D. Díaz Sánchez. "Decoupling path failure detection from congestion control
to improve SCTP failovers." Journal/Magazine: IEEE COMMUN LETT. Vol:12. Issue:
11 (2008): Pages:858–860.
Abstract
: SCTP handover is too slow to be useful as a mobility solution for
most applications. With quicker handovers, SCTP will be an interesting solution
to mobility. SCTP uses retransmissions as probes for path failure detection. Congestion
control forces slow paced retransmissions but quick failovers need fast paced probes.
Our solution is to stop using retransmissions as probes. Instead, we propose active
path monitoring using unreliable heartbeats. Applications can tune this algorithm
to meet their own requirements. We show data from a simple experiment in a real
environment.
Keywords: Computer network reliability; congestion control; transport
protocols
Díaz-Sánchez, D., A. Marín, F. Almenarez, C. Campo, A. Cortés, and C. García-Rubio.
"Trust Negotiation Protocol Support for Secure Mobile Network Service Deployment."
Wireless and Mobile Networking. Ed. Springer Boston. Vol. 284/2008., 2008.
271–282.
Abstract
: User-centric services might enforce requirements difficult to be
endorsed by visited networks unless tight coupled trust relations are previously
established among providers. Maintaining those fixed trust relations is costly and
unmanageable if the number of providers increases. Moreover, it requires providers
to use a common security model, credentials, policies…Trust Negotiation can be the
solution to this problem since allows to negotiate gradually a security state enabling
multiple factor authentication and authorization even for “strangers” by exchanging
various credentials. However, there are still two problems to solve, the first one
is the delay introduced by the trust negotiation messages if used as bootstrapping
in every interaction; the second one is the lack of protocol support. In this article
we address those problems by presenting an extension to TLS that enables trust negotiation
and credential issuing (to speed-up following interactions) over a secure channel.
Diaz-Sanchez, D., A. Marin, F. Almenarez, and A. Cortes. "DVB-H Key Management System
for UMTS Capable Devices.", 2008. 1–2.
Abstract
: In this paper we present a system to enable pay-per- view services
in mobile handhelds which takes benefits of both DVB-H and UMTS networks. DVB-H
infrastructure provides a more appropriate content delivery framework that UMTS.
Despite this fact, UMTS can play an important role for charging and key distribution
for pay-per-view applications by means of the provider SIM smart card.
Keywords: 3G mobile communication, cryptography, digital video
broadcasting, telecommunication network managementDVB-H key management system, SIM
smart card, UMTS capable devices, content delivery framework, mobile handhelds,
pay-per-view services
2007
Díaz Sánchez, D., A. Marín López, F. Almenárez Mendoza, C. Campo Vázquez, and C.
García-Rubio. "Context awareness in network selection for dynamic environments."
Journal/Magazine: Telecommunication Systems. Vol:36. Issue: 1 (2007): Pages:49–60.
Abstract
: Abstract Mobile devices of new generation are able to connect to
multiple networks and to constitute new infrastructureless networks. These dynamic
environments require new security paradigms and automatic mechanisms to minimize
user intervention. Our goal is the definition of a new concept of distance that
considers the current domain constraints and the user preferences. This paper addresses
some of the problems of these complex environments by using Multidimensional Scaling
(MDS) techniques. We also propose collaborative mechanisms for automatic environment
marking. Based on these ideas we have developed Pervasive Interaction Manager (PervsIM),
a decision mechanism that selects the most appropriate network or peer to interact
with. Besides we have defined an embedded access control module which ensures that
PervsIM decisions are followed by all applications. Furthermore, several simulation
results and implementation details outline how these results can be incorporated
in today’s mobile devices.
Keywords: Context-awareness;Network selection;Mobile devices;Pervasive
computing
Díaz-Sánchez, D., A. Marín, and F. Almenárez. "Enhancing access control for mobile
devices with an agnostic trust negotiation decision engine." Personal Wireless Communications.
Ed. Springer Boston., 2007. 304–315.
Abstract
: Dynamic open environments demand trust negotiation systems for unknown
entities willing to communicate. A security context has to be negotiated gradually
in a fair peer to peer basis depending on the security level demanded by the application.
Trust negotiation engines are driven by decision engines that lack of flexibility:
depend on the implementation, policies languages or credentials types to be used.
In this paper we present an agnostic engine able to combine all that information
despite its origin or language allowing to select policies or requirements, credentials
and resources to disclose, according to user preferences and context using iterative
weighted Multidimensional Scaling to assist a mobile device during a trust negotiation.
Keywords: trust negotiation;access control;flexible
Marín López, A., D. Díaz-Sánchez, F. Almenárez, C. García-Rubio, and C. Campo. "Smart
card-based agents for fair non-repudiation." Journal/Magazine: Computer Networks.
Vol:51. Issue: 9 (2007): Pages:2288–2298.
Abstract
: Non-repudiation protocols are of great importance for electronic
interactions. Different protocols have been proposed in this field, progressively
relaxing the requirements on the computing power of both parties, and on the load
and involvement of a trusted third party (TTP). Besides, there is a need to provide
mobile users with a protocol adequate for ad hoc scenarios, where only unreliable
channels can be guaranteed, and where the CA may not be reachable. In this paper
we propose a new version of the fair non-repudiation protocol proposed by Gürgens
et al. in [Sigrid Gürgens, Carsten Rudolph, Holger Vogt, On the security of fair
non-repudiation protocols, in: Colin Boyd, Wenbo Mao (Eds.), ISC, Lecture Notes
in Computer Science, vol. 2851, Springer, 2003, pp. 193-207]. We show unfair scenarios
that can appear if one party controls the communication among the TTP and the other
party. We introduce notary agents, which play the TTP role, and run our fair non-repudiation
protocol. Notary agents execute inside the smart card, and sign the protocol messages
with the user’s private key on his behalf. Our approach enables the protocol to
run on unreliable channels, disconnected from the CA.
Keywords: Fairness; Non-repudiation protocol; Smart card; Unreliable
channels; Electronic transactions; Ad hoc mode
Schaefer R., W. Mueller, A. Marín López, and D. Díaz Sánchez. Using Smart Cards for
Secure and Device Independent User Interfaces . Singapore, 10-12 September
2007, 2007.
Abstract
: Smart Cards are becoming a ubiquitous means for securing a wide range
of interactive applications. However in many cases its use is limited for authentication
purposes only. In this paper we extend the use of smart cards for carrying abstract
user interface descriptions which can be rendered on different and potentially remote
clients that in addition can support varying interaction modalities. This adds on
the one hand to the security since a backend application cannot be used without
the UI description, and on the other hand to the versatility of applications, since
all devices with a respective renderer for certain modalities can be utilized.
Keywords: Smart Card; Abstract User Interface; Device Independence
Schaefer R., W. Mueller, A. Marín López, and D. Díaz Sánchez. "Device Independent
User Interfaces for Smart Cards." 9th International Conference on Human Computer
Interaction with Mobile Devices and Services (MobileHCI 2007) . Singapore,
9-12 September 2007, 2007.
Abstract
: Smart Cards are becoming a ubiquitous means for securing a wide range
of interactive applications. However in many cases its use is limited for authentication
purposes only. In this paper we extend the use of smart cards for carrying abstract
user interface descriptions which can be rendered on different and potentially remote
clients that in addition can support different interaction modalities. This adds
on the one hand to the security since a backend application cannot be used without
the UI description, and on the other hand to the versatility of applications, since
all devices with a respective renderer for certain modalities can be utilized.
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