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J. Lopez, J. E. Rubio, and C. Alcaraz, "A Resilient Architecture for the Smart Grid",
IEEE Transactions on Industrial Informatics, vol. 14, issue 8, IEEE, pp. 3745-3753, 08/2019, 2018. DOI (I.F.: 7.377)More..


The Smart Grid offers many benefits due to the bidirectional communication between the users and the utility company, which makes it possible to perform a fine-grain consumption metering. This can be used for Demand Response purposes with the generation and delivery of electricity in real time. It is essential to rapidly anticipate high peaks of demand or potential attacks, so as to avoid power outages and denial of service, while effectively supplying consumption areas. In this paper, we propose a novel architecture where cloud computing resources are leveraged (and tested in practice) to enable, on the one hand, the consumption prediction through time series forecasting, as well as load balancing to uniformly distribute the demand over a set of available generators. On the other and, it also allows the detection of connectivity losses and intrusions within the control network by using controllability concepts.

Impact Factor: 7.377
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

PDF icon transactionInformaticsSG2018.pdf (609.25 KB)
J. E. Rubio, C. Alcaraz, and J. Lopez, "Recommender System for Privacy-Preserving Solutions in Smart Metering",
Pervasive and Mobile Computing, vol. 41, Pervasive and Mobile Computing, pp. 205-218, 10/2017. (I.F.: 2.974)More..


Nowadays, Smart Grid is envisaged to provide several benefits to both customers and grid operators. However, Smart Meters introduce many privacy issues if consumption data is analysed. In this paper we analyse the main techniques that address privacy when collecting electricity readings. In addition to privacy, it is equally important to preserve efficiency to carry on with monitoring operations, so further control requirements and communication protocols are also studied. Our aim is to provide guidance to installers who intend to integrate such mechanisms on the grid, presenting an expert system to recommend an appropriate deployment strategy.

Impact Factor: 2.974
Journal Citation Reports® Science Edition (Thomson Reuters, 2017)

PDF icon rubiorecommender17.pdf (461.99 KB)
C. Alcaraz, J. Lopez, and K-K. Raymond Choo, "Resilient Interconnection in Cyber-Physical Control Systems",
Computers & Security, vol. 71, Elsevier, pp. 2-14, 11/2017. DOI (I.F.: 2.650)More..


Secure interconnection between multiple cyber-physical systems has become a fundamental requirement in many critical infrastructures, where security may be centralized in a few nodes of the system. These nodes could, for example, have the mission of addressing the authorization services required for access in highlyrestricted remote substations. For this reason, the main aim of this paper is to unify all these features, together with the resilience measures so as to provide control at all times under a limited access in the field and avoid congestion. Concretely, we present here an optimal reachability-based restoration approach, capable of restoring the structural control in linear times taking into account: structural controllability, the supernode theory, the good practices of the IEC-62351 standard and the contextual conditions. For context management, a new attribute is specified to provide a more complete authorization service based on a practical policy, role and attribute-based access control (PBAC + RBAC + ABAC). To validate the approach, two case studies are also discussed under two strategic adversarial models.

Impact Factor: 2.650
Journal Citation Reports® Science Edition (Thomson Reuters, 2017)

PDF icon Alcaraz2017COSE.pdf (5.27 MB)
N. Nomikos, et al., "Relay Selection for Secure 5G Green Communications",
Telecommunication Systems , vol. 59, issue 1, Springer US, pp. 169-187, 05/2015. DOI (I.F.: 0.822)More..


In this article, we present relay selection policies in applications with secrecy requirements which are of interest in the fifth generation (5G) of wireless networks. More specifically, we provide a classification of relays based on their distinct communication attributes, such as processing, multiple antennas, storage, channel estimation, density and security level. In addition, we discuss the level of efficiency exhibited by each relay class, regarding their impact in delay-critical applications and green communications applications, while aiming at a specific security level at the physical layer. Then, relay selection policies are proposed taking into consideration the goals set by each application. Numerical evaluation of the proposed policies in terms of the average secrecy rate, average delay and power reduction show improved performance compared to other state-of-the-art solutions. 

Impact Factor: 0.822
Journal Citation Reports® Science Edition (Thomson Reuters, 2015)

R. Rios, J. Cuellar, and J. Lopez, "Robust Probabilistic Fake Packet Injection for Receiver-Location Privacy in WSN",
17th European Symposium on Research in Computer Security (ESORICS 2012), S. Foresti, M. Yung, and F. Martinelli Eds., LNCS 7459, Springer, pp. 163-180, Sep 2012. DOI More..


The singular communication model in wireless sensor networks (WSNs) originate pronounced traffic patterns that allow a local observer to deduce the location of the base station, which must be kept secret for both strategical and security reasons. In this work we present a new receiver-location privacy solution called HISP (Homogenous Injection for Sink Privacy). Our scheme is based on the idea of hiding the flow of real traffic by carefully injecting fake traffic to homogenize the transmissions from a node to its neighbors. This process is guided by a lightweight probabilistic approach ensuring that the adversary cannot decide with sufficient precision in which direction to move while maintaining a moderate amount of fake traffic. Our system is both validated analytically and experimentally through simulations.

PDF icon Rios2012d.pdf (524.61 KB)
P. Najera, and J. Lopez, "Real-time Location and Inpatient Care Systems Based on Passive RFID",
Journal of Network and Computer Applications, vol. 34, Elsevier, pp. pp. 980-989, 2011. DOI (I.F.: 1.065)More..


RFID technology meets identification and tracking requirements in healthcare environments with potential to speed up and increase reliability of involved processes. Due to this, high expectations for this integration have emerged, but hospital and medical centers interested in adoption of RFID technology require prior knowledge on how to squeeze RFID capabilities, real expectations and current challenges. In this paper, we show our lab tested solutions in two specific healthcare scenarios. On the one hand, we analyze the case of a medical equipment tracking system for healthcare facilities enabling both real-time location and theft prevention. Worth-noting aspects such as possible EMI interferences, technology selection and management of RFID data from hospital information system are analyzed. Lab testing of system reliability based on passive UHF RFID is provided for this case. On the other hand, we analyze and provide a solution for care and control of patients in a hospital based on passive HF RFID with the result of a fully functional demonstrator. Our prototype squeezes RFID features in order to provide a backup data source from patient’s wristband. It also provides an offline working mode aiming to increase application reliability under network fail down and therefore, improving patient’s safety. Considerations regarding lessons learned and challenges faced are exposed.

Impact Factor: 1.065
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon Najera2010.pdf (241.66 KB)
D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Reusable Security Use Cases for Mobile Grid environments",
Workshop on Software Engineering for Secure Systems, IEEE, pp. 1-8, 2009. More..



Due to the growing complexity of softwaredevelopment, developing software through systematicprocesses is becoming more and more important.Likewise, it is important that the development processused integrates security aspects from the first stages atthe same level as other functional and non-functionalrequirements. In the last years, GRID technology hasshown to be the most important one and it allows us tobuild very complex information systems with differentand remarkable features (interoperability betweenmultiple security domains, cross-domainauthentication and authorization, dynamic,heterogeneous and limited mobile devices, etc).Traditionally, systems based on GRID Computing havenot been developed through adequate methodologiesand have not taken into account security requirementsthroughout their development, only offering securitytechnical solutions at the implementation stages. Thispaper shows part of a development methodology thatwe are elaborating for the construction of informationsystems based on Grid Computing highly dependent onmobile devices where security plays a very importantrole. Specifically, in this paper, we will present theanalysis phase, managed by reusable use casesthrough which we can define the requirements andneeds of these systems obtaining an analysis modelthat can be used as input to the following phase of themethodology, the design phase of mobile Grid systems.



PDF icon rosado2009b.pdf (444.47 KB)
D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Reutilización de Casos de Uso en el Desarrollo de Sistemas Grid seguros",
XII Conferencia Iberoamericana de Ingeniería de Requisitos y Ambientes de Software (IDEAS’09), University of Colombia, pp. 388-393, 2009. More..


El desarrollo software debe estar basado en un proceso sistemático y estructurado donde se definan los métodos y técnicas a utilizar en todo su ciclo de vida, ayudando así a obtener un producto de calidad. Es igualmente importante que el proceso sistemático considere aspectos de seguridad desde las primeras etapas, integrándola como un elemento más en el ciclo de desarrollo. En este artículo mostramos la metodología de desarrollo sistemático que sirve de guía para el desarrollo de cualquier sistema Grid con dispositivos móviles, considerando la seguridad durante todas las fases de desarrollo, lo que nos permitirá obtener como resultado sistemas Grid seguros, robustos y escalables. Este artículo presenta la fase de análisis, dirigida por casos de uso reutilizables, mediante los cuales se definen los requisitos y necesidades de estos sistemas, y es aplicada a un caso de estudio real de un Grid para el acceso de contenidos multimedia en un contexto periodístico.


P. Najera, and J. Lopez, "RFID: Technological Issues and Privacy Concerns",
Digital Privacy: Theory, Technologies, and Practices, A.. Acquisti, S. Gritzalis, C.. Lambrinoudakis, and S. De Capitan di Vimercati Eds., Auerbach Publications, pp. 285-306, December, 2007. More..
PDF icon Najera2007.pdf (137.2 KB)
R. Roman, C. Alcaraz, and J. Lopez, "The Role of Wireless Sensor Networks in the Area of Critical Information Infrastructure",
Information Security Technical Report, vol. 12, no. 1, Elsevier, pp. 24-31, 2007. DOI More..


Critical Infrastructures, such as energy, banking, and transport, are an essential pillar to the well-being of the national and international economy, security and quality of life. These infrastructures are dependent on a spectrum of highly interconnected information infrastructures for their smooth, reliable and continuous operation. The field of protecting such Critical Information Infrastructures, or CIIP, faces numerous challenges, such as managing the secure interaction between peers, assuring the resilience and robustness of the overall system, and deploying warning and alert systems, amongst others. In this tapestry of CIIP, Wireless Sensor Networks can be used as an invaluable tool due to their intelligent distributed control capabilities, alongside with their capability to work under severe conditions. In this paper, we justify why Wireless Sensor Networks technology is suitable for providing security for these scenarios, describing both their advantages and research issues and their role in the overall scheme of protecting the Critical Information Infrastructures.

PDF icon Roman2007a.pdf (183.54 KB)
I. Agudo, J. Lopez, and J. A. Montenegro, "A Representation Model of Trust Relationships with Delegation Extensions",
3th International Conference on Trust Management (iTRUST’05), LNCS 3477, Springer, pp. 9-22, May, 2005. DOI More..


Logic languages establish a formal framework to solve authorization and delegation conflicts. However, we consider that a visual representation is necessary since graphs are more expressive and understandable than logic languages. In this paper, and after overviewing previous works using logic languages, we present a proposal for graph representation of authorization and delegation statements. Our proposal is based on Varadharajan et al. solution, though improve several elements of that work. We also discuss about the possible implementation of our proposal using attribute certificates.

PDF icon IsaacAgudo2005b.pdf (251.54 KB)
J. Lopez, A. Mana, P. Merino, and J. M. Troya, "The Role of Smartcards in Practial Information Security",
ERCIM News, vol. 49, pp. 38-40, 2002. More..


The transition from traditional commerce to electronic and mobile commerce is fostered by aspects like convenience, speed and ease of use. However, security issues remain unsolved. Smart cards open new possibilities for the development of security schemes and protocols that can provide security in applications such as electronic payments or software protection where traditional cryptographic tools are not useful. The GISUM group is involved in several research projects that make use of smart cards. Current applications include a secure electronic forms framework for government-citizen relations, electronic ticketing systems for GMS phones and Internet, a PDA-based digital signature environment, public transport, access control systems, software protection and banking applications. This report focuses on two recent projects: the eTicket electronic ticketing project (1FD97 1269 C02 02 (TAP)), a coordinated project with the Carlos III University of Madrid; and the Alcance project, consisting of the development of a secure electronic forms framework for secure Internet-based communication between citizens and the public administration (1FD97 0850 (TIC)).

PDF icon JavierLopez2002d.pdf (119.71 KB)
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