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J. Areitio, and J. Lopez, "Contribuciones de la Tecnología de Detección y Respuesta a Intrusiones y Ataques a la Construcción de la Confianza",
Novática, vol. 141, pp. 24-27, 1999.
J. Areitio, J. Lopez, and J. M. Troya, "Horizontes y Tendencias de Seguridad en Internet",
Novática, vol. 145, pp. 65-71, 2000. More..


  El comercio electrónico está llamado a ser el fenómeno de mayor importancia en el futuro de Internet. Entre sus aplicaciones se encuentran las compras en línea, la banca electrónica, la tele-educación, los casinos virtuales, los servicios de pago por visión y vídeo bajo demanda, etc. Desde el punto de vista de la Seguridad, estas aplicaciones presentan una serie de nuevos requisitos que van a imponer un gran esfuerzo investigador a corto y medio plazo. En este artículo se presentan algunos de los más importantes, como la administración de la confianza, la utilización de pagos electrónicos, la necesidad de la protección de la propiedad intelectual, los servicios de protección de privacidad y anonimato, y la autonomía de código y la detección de fraudes, identificándose las áreas de investigación relacionadas.

PDF icon JavierAreitio2000.pdf (95.24 KB)
C. Alcaraz, J. Lopez, and S. Wolthunsen, "OCPP Protocol: Security Threats and Challenges",
IEEE Transactions on Smart Grid, vol. 8, issue 5, IEEE, pp. 2452 - 2459, 02/2017. DOI (I.F.: 7.364)More..


One benefit postulated for the adoption of Electric Vehicles (EVs) is their ability to act as stabilizing entities in smart grids through bi-directional charging, allowing local or global smoothing of peaks and imbalances. This benefit, however, hinges indirectly on the reliability and security of the power flows thus achieved. Therefore this paper studies key security properties of the alreadydeployed Open Charge Point Protocol (OCPP) specifying communication between charging points and energy management systems. It is argued that possible subversion or malicious endpoints in the protocol can also lead to destabilization of power networks. Whilst reviewing these aspects, we focus, from a theoretical and practical standpoint, on attacks that interfere with resource reservation originating with the EV, which may also be initiated by a man in the middle, energy theft or fraud. Such attacks may even be replicated widely, resulting in over- or undershooting of power network provisioning, or the (total/partial) disintegration of the integrity and stability of power networks.

Impact Factor: 7.364
Journal Citation Reports® Science Edition (Thomson Reuters, 2017)

PDF icon AlcarazLopezWolthusen2017.pdf (389.27 KB)
C. Alcaraz, and J. Lopez, "WASAM: A Dynamic Wide-Area Situational Awareness Model for Critical Domains in Smart Grids",
Future Generation Computer Systems, vol. 30, Elsevier, pp. 146-154, 2014. DOI (I.F.: 2.786)More..


Control from anywhere and at anytime is nowadays a matter of paramount importance in critical systems. This is the case of the Smart Grid and its domains which should be monitored through intelligent and dynamic mechanisms able to anticipate, detect and respond before disruptions arise within the system. Given this fact and its importance for social welfare and the economy, a model for wide-area situational awareness is proposed in this paper. The model is based on a set of current technologies such as the wireless sensor networks, the ISA100.11a standard and cloud-computing together with a set of high-level functional services. These services include global and local support for prevention through a simple forecast scheme, detection of anomalies in the observation tasks, response to incidents, tests of accuracy and maintenance, as well as recovery of states and control in crisis situations.

Impact Factor: 2.786
Journal Citation Reports® Science Edition (Thomson Reuters, 2014)

PDF icon alcaraz2013b.pdf (956.89 KB)
C. Alcaraz, C. Fernandez-Gago, and J. Lopez, "An Early Warning System based on Reputation for Energy Control Systems",
IEEE Transactions on Smart Grid, vol. 2, no. 4, IEEE, pp. 827-834, Nov 2011. DOI More..


Most of energy control or SCADA (Supervisory Control and Data Acquisition) systems are very dependent on advanced technologies and on traditional security mechanisms for protecting the a system against anomalous events. Security mechanisms are not enough to be used in critical systems, since they can only detect anomalous events occurring at a certain moment in time. For this reason it becomes of paramount importance the usage of intelligent systems with capability for preventing anomalous situations and reacting against them on time. This type of systems are, for example, Early Warning Systems (EWS). In this paper, we propose an EWS based on Wireless Sensor Networks (WSNs) (under the ISA100.11a standard) and reputation for controling the network behaviour. The WSN are organized into clusters where a Cluster Head (CH) is designated. This CH will contain a Reputation Manager Module. The usability of this approach is also analyzed considering a Smart Grid scenario.} keywords = {Critical Information Infrastructures, Sensor Networks, Early Warning Systems, Reputation, SCADA Systems, Smart Grid.

PDF icon Alcaraz2011.pdf (495.57 KB)
C. Alcaraz, "Cloud-Assisted Dynamic Resilience for Cyber-Physical Control Systems",
IEEE Wireless Communications, vol. 25, no. 1, IEEE, pp. 76-82, 02/2018. DOI (I.F.: 11)More..
Impact Factor: 11
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

PDF icon Alcaraz2018a.pdf (3.46 MB)
C. Alcaraz, and S.. Zeadally, "Critical Control System Protection in the 21st Century: Threats and Solutions",
IEEE Computer, vol. 46, no. 10, IEEE Computer Society, pp. 74 - 83, 2013. DOI (I.F.: 1.438)More..


Information systems, networks, and technologies have become an integral part of modern critical control systems that manage many of today’s critical infrastructures. The continuous operation, maintenance, and protection of critical infrastructures have become a high national priority for governments around the world because our society heavily depends on them for most of our daily activities (travel, power usage, banking transactions, telecommunications, etc) and safety. It is therefore critical that these infrastructures have to be protected from potential accidental incidents or cyberattacks. We present the fundamental architectural components of critical control systems which manage most critical infrastructures. We identify some of the vulnerabilities and threats to modern critical control systems followed by protection solutions that can be deployed to mitigate attacks exploiting these vulnerabilities.

Impact Factor: 1.438
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

C. Alcaraz, J. Lopez, and S. Wolthusen, "Policy Enforcement System for Secure Interoperable Control in Distributed Smart Grid Systems",
Journal of Network and Computer Applications, vol. 59, Elsevier, pp. 301–314, 01/2016. (I.F.: 3.500)More..


Interoperability of distributed systems in charge of monitoring and maintaining the different critical domains belonging to Smart Grid scenarios comprise the central topic of this paper. Transparency in control transactions under a secure and reliable architecture is the aim of the policy enforcement system proposed here. The approach is based on the degree of observation of a context and on the role-based access control model defined by the IEC-62351-8 standard. Only authenticated and authorised entities are able to take control of those distributed elements (e.g., IEC-61850 objects) located at distant geographical locations and close to the critical infrastructures (e.g., substations). To ensure the effectiveness of the approach, it is built on graphical-theoretical formulations corresponding to graph theory, where it is possible to illustrate power control networks through power-law distributions whose monitoring relies on structural controllability theory. The interconnection of these distributions is subject to a network architecture based on the concept of the supernode where the interoperability depends on a simple rule-based expert system. This expert system focuses not only on accepting or denying access, but also on providing the means to attend to extreme situations, avoiding, as much as possible, the overloading of the communication. Through one practical study we also show the functionalities of the approach and the benefits that the authorisation itself can bring to the interoperability

Impact Factor: 3.500
Journal Citation Reports® Science Edition (Thomson Reuters, 2016)

PDF icon alcaraz2016POL.pdf (1.81 MB)
C. Alcaraz, and J. Lopez, "Analysis of Requirements for Critical Control Systems",
International Journal of Critical Infrastructure Protection (IJCIP), vol. 5, Elsevier, pp. 137–145, 2012. DOI (I.F.: 0.63)More..


The use of modern information and communications technologies in supervisory control and data acquisition (SCADA) systems used in the critical infrastructure has become an important topic of research. The modernization significantly enhances operational performance, but also introduces security issues and the associated risks. This paper formally analyzes how the introduction of new technologies can impact control systems and ultimately affect the performance of the critical infrastructure systems being controlled. Five control system requirements are identified with the goal of proposing new operational requirements that trade-off performance and security.

Impact Factor: 0.63
Journal Citation Reports® Science Edition (Thomson Reuters, 2012)

PDF icon 1730.pdf (705.14 KB)
C. Alcaraz, and J. Lopez, "A Cyber-Physical Systems-Based Checkpoint Model for Structural Controllability",
IEEE Systems Journal, vol. 12, issue 4, IEEE, pp. 3543-3554, 12/2018. DOI (I.F.: 4.463)More..


The protection of critical user-centric applications, such as Smart Grids and their monitoring systems, has become one of the most cutting-edge research areas in recent years. The dynamic complexity of their cyber-physical systems (CPSs) and their strong inter-dependencies with power systems, are bringing about a significant increase in security problems that may be exploited by attackers. These security holes may, for example, trigger the disintegration of the structural controllability properties due to the problem of non-locality, affecting, sooner or later, the provision of the essential services to end-users. One way to address these situations could be through automatic checkpoints in charge of inspecting the healthy status of the control network and its critical nature. This inspection can be subject to special mechanisms composed of trustworthy cyberphysical elements capable of detecting structural changes in the control and activating restoration procedures with support for warning. This is precisely the aim of this paper, which presents a CPSs-based checkpoint model with the capacity to manage heterogeneous replications that help ensure data redundancy, thereby guaranteeing the validity of the checkpoints. As a support to this study, a theoretical and practical analysis is addressed to show the functionality of the approach in real contexts.

Impact Factor: 4.463
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

PDF icon alcarazlopez-IEEESystems-2017.pdf (890.76 KB)
C. Alcaraz, and J. Lopez, "FACIES: online identification of Failure and Attack on interdependent Critical InfrastructurES",
European CIIP Newsletter, vol. 7, European_CIIP_Newsletter, pp. 11-13, Nov 2013. More..


 FACIES aims to protect water treatment systems and their control systems against accidental or intentional incidents such as failures, anomalies and cyber-attacks with a particular emphasis on stealth attacks.

C. Alcaraz, and J. Lopez, "A Security Analysis for Wireless Sensor Mesh Networks in Highly Critical Systems",
IEEE Transactions on Systems, Man, and Cybernetics, Part C: Applications and Reviews, vol. 40, no. 4, IEEE, pp. 419-428, July, 2010. DOI (I.F.: 2.105)More..


Nowadays, critical control systems are a fundamental component contributing to the overall performance of critical infrastructures in our society, most of which belong to the industrial sector. These complex systems include in their design different types of information and communication technology systems, such as wireless (mesh) sensor networks, to carry out control processes in real time. This fact has meant that several communication standards, such as Zigbee PRO, WirelessHART, and ISA100.11a, have been specified to ensure coexistence, reliability, and security in their communications. The main purpose of this paper has been to review these three standards and analyze their security. We have identified a set of threats and potential attacks in their routing protocols, and we consequently provide recommendations and countermeasures to help Industry protect its infrastructures.

Impact Factor: 2.105
Journal Citation Reports® Science Edition (Thomson Reuters, 2010)

PDF icon Alcaraz2010a.pdf (557 KB)
C. Alcaraz, and S. Zeadally, "Critical Infrastructure Protection: Requirements and Challenges for the 21st Century",
International Journal of Critical Infrastructure Protection (IJCIP), vol. 8, Elsevier Science, pp. 53–66, 01/2015. DOI (I.F.: 1.351)More..


Critical infrastructures play a vital role in supporting modern society. The reliability, performance, continuous operation, safety, maintenance and protection of critical infrastructures are national priorities for countries around the world. This paper explores the vulnerabilities and threats facing modern critical infrastructures with special emphasis on industrial control systems, and describes a number of protection measures. The paper also discusses some of the challenging areas related to critical infrastructure protection such as governance and security management, secure network architectures, self-healing, modeling and simulation, wide-area situational awareness, forensics and learning, and trust management and privacy.

Impact Factor: 1.351
Journal Citation Reports® Science Edition (Thomson Reuters, 2015)

PDF icon alcaraz2015CRI.pdf (4.03 MB)
C. Alcaraz, J. E. Rubio, and J. Lopez, "Blockchain-Assisted Access for Federated Smart Grid Domains: Coupling and Features",
Journal of Parallel and Distributed Computing, vol. 144, Elsevier, pp. 124-135, 06/2020. (I.F.: 3.734)More..
Impact Factor: 3.734
Journal Citation Reports® Science Edition (Thomson Reuters, 2020)

PDF icon Alcaraz2020a.pdf (2.53 MB)
C. Alcaraz, J. Lopez, R. Roman, and H-H. Chen, "Selecting key management schemes for WSN applications",
Computers & Security, vol. 31, no. 38, Elsevier, pp. 956–966, Nov 2012. DOI (I.F.: 1.158)More..


Key management in wireless sensor networks (WSN) is an active research topic. Due to the fact that a large number of key management schemes (KMS) have been proposed in the literature, it is not easy for a sensor network designer to know exactly which KMS best fits in a particular WSN application. In this article, we offer a comprehensive review on how the application requirements and the properties of various key management schemes influence each other. Based on this review, we show that the KMS plays a critical role in determining the security performance of a WSN network with given application requirements. We also develop a method that allows the network designers to select the most suitable KMS for a specific WSN network setting. In addition, the article also addresses the issues on the current state-of-the-art research on the KMS for homogeneous (i.e. non-hierarchical) networks to provide solutions for establishing link-layer keys in various WSN applications and scenarios.

Impact Factor: 1.158
Journal Citation Reports® Science Edition (Thomson Reuters, 2012)

PDF icon AlcarazR2012.pdf (326.12 KB)
C. Alcaraz, G. Fernandez, R. Roman, A. Balastegui, and J. Lopez, "Secure Management of SCADA Networks",
Novatica, New Trends in Network Management, vol. 9, no. 6, Cepis UPGRADE, pp. 22-28, December, 2008. More..


When a Supervisory Control and Data Acquisition (SCADA) system monitors and manages other complex infrastructures through the use of distributed technologies, it becomes a critical infrastructure by itself: A failure or disruption in any of its components could implicate a serious impact on the performance of the other infrastructures. The connection with other systems makes a SCADA system more vulnerable against attacks, generating new security problems. As a result, it is essential to perform diverse security analysis frequently in order to keep an updated knowledge and to provide recommendations and/or solutions to mitigate or avoid anomalous events. This will facilitate the existence of a suitable, reliable, and available control network.

PDF icon Alcaraz2008b.pdf (325.52 KB)
C. Alcaraz, "Resilient Industrial Control Systems based on Multiple Redundancy",
International Journal of Critical Infrastructures (IJCIS), vol. 13, no. 2/3, Inderscience Publisher, pp. 278 - 295, 11/2017. DOI More..


The incessant search for cost-effective recovery solutions for structural controllability has led to one of the most challenging research areas within the field of critical infrastructure protection. The resilience of large heterogeneous distributions, like industrial control scenarios, is proving to be a complicated mission due to the inherent non-locality problems of structural controllability and its susceptibility to advanced threats. To address these issues, this paper proposes a new repair approach based on multiple redundant pathways and the lessons learnt from the work presented in [1]. From [1], we have adapted the local measures, to combine them with each of the five strategies of remote reconnection described in this paper. To validate the sustainability of the combined approaches, two practical case studies are presented here, showing that a local dependence on a brother driver node together with remote dependence is enough to reach optimal states in linear times.

C. Alcaraz, G. Bernieri, F. Pascucci, J. Lopez, and R. Setola, "Covert Channels-based Stealth Attacks in Industry 4.0",
IEEE Systems Journal., vol. 13, issue 4, IEEE, pp. 3980-3988, 12/2019. DOI (I.F.: 3.987)More..


Industry 4.0 advent opens several cyber-threats scenarios originally designed for classic information technology, drawing the attention to the serious risks for the modern industrial control networks. To cope with this problem, in this paper we address the security issues related to covert channels applied to industrial networks, identifying the new vulnerability points when information technologies converge with operational technologies such as edge computing infrastructures. Specifically, we define two signaling strategies where we exploit the Modbus/TCP protocol as target to set up a covert channel. Once the threat channel is established, passive and active offensive attacks (i.e. data exfiltration and command an control, respectively) are further exploited by implementing and testing them on a real Industrial Internet of Things testbed. The experimental results highlight the potential damage of such specific threats, and the easy extrapolation of the attacks to other types of channels in order to show the new risks for Industry 4.0. Related to this, we discuss some countermeasures to offer an overview of possible mitigation and defense measures.

Impact Factor: 3.987
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)

PDF icon alcaraz2019a.pdf (938.98 KB)
C. Alcaraz, and J. Lopez, "Wide-Area Situational Awareness for Critical Infrastructure Protection",
IEEE Computer, vol. 46, no. 4, IEEE Computer Society, pp. 30-37, 2013. DOI (I.F.: 1.438)More..


Combining a wide-area situational awareness (WASA) methodological framework with a set of requirements for awareness construction can help in the development and commissioning of future WASA cyberdefense solutions


Impact Factor: 1.438
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

PDF icon 1761.pdf (1.56 MB)
C. Alcaraz, G. Fernandez, R. Roman, A. Balastegui, and J. Lopez, "Gestión segura de redes SCADA",
Nuevas tendencias en gestión de redes, Novática, no. 196, CEPIS, pp. 20-25, December, 2008. More..


En el momento que se introduce en el mercado nuevas tecnologías basadas en entornos distribuidos comienzan a surgir en paralelo nuevos problemas de seguridad en los sistemas SCADA (Supervisory Control and Data Acquisition), los cuales monitorizan y gestionan otras infraestructuras de gran complejidad y escala. Un fallo o una interrupción en uno de sus componentes podría suponer un impacto negativo sobre la funcionalidad de otras infraestructuras, por lo que se hace necesario realizar frecuentes análisis de seguridad para así mantener actualizado el conocimiento y proveer recomendaciones y/o soluciones para mitigar o evitar futuras ocurrencias, garantizando una gestión de red fiable y siempre disponible.

PDF icon Alcaraz2008a.pdf (329.92 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)
C. Alcaraz, and J. Lopez, "Diagnosis Mechanism for Accurate Monitoring in Critical Infrastructure Protection",
Computer Standards & Interfaces, vol. 36, issue 3, Elsevier, pp. 501-512, 2014. DOI (I.F.: 0.879)More..


 Situational awareness for critical infrastructure protection, such as for energy control systems, has become a topic of interest in recent years. Despite attempts to address this area of research, more progress is still necessary to find attractive solutions that help bring about prevention and response at all times from anywhere and at any time. Given this need, we therefore propose in this paper, a smart mechanism able to offer a wide-area situational awareness with the ability to: (i) Control the real state of the observed infrastructure, (ii) respond to emergency situations and (iii) assess the degree of  ccuracy of the entire control system. To address these aspects, the mechanism is based on a hierarchical configuration of industrial sensors for control, the ISA100.11a standard for the prioritization and alarm management, and the F-Measure technique to study the level of accuracy of a sensor inside a neighbourhood. As proof of the functionality and feasibility of the mechanism for critical contexts, a software application implemented in nesC and Java is also presented in this paper.

Impact Factor: 0.879
Journal Citation Reports® Science Edition (Thomson Reuters, 2014)

PDF icon alcaraz2013a.pdf (1.94 MB)
C. Alcaraz, J. Lopez, J. Zhou, and R. Roman, "Secure SCADA Framework for the Protection of Energy Control Systems",
Concurrency and Computation Practice & Experience, vol. 23, no. 12, John Wiley & Sons, Inc., pp. 1414-1430, Aug 2011. DOI (I.F.: 0.636)More..


Energy distribution systems are becoming increasingly widespread in today’s society. One of the elements that is used to monitor and control these systems are the SCADA (Supervisory Control and Data Acquisition) systems. In particular, these control systems and their complexities, together with the emerging use of the Internet and wireless technologies, bring new challenges that must be carefully considered. Examples of such challenges are the particular bene¯ts of the integration of those new technologies, and also the e®ects they may have on the overall SCADA security. The main task of this paper is to provide a framework that shows how the integration of di®erent state-of-the-art technologies in an energy control system, such as Wireless Sensor Networks (WSNs), Mobile Ad-Hoc Networks (MANETs), and the Internet, can bring some interesting benefits such as status management and anomaly prevention, while maintaining the security of the whole system.

Impact Factor: 0.636
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon Alcaraz2011a.pdf (908.82 KB)
C. Alcaraz, R. Roman, P. Najera, and J. Lopez, "Security of Industrial Sensor Network-based Remote Substations in the context of the Internet of Things",
Ad Hoc Networks, vol. 11, Elsevier, pp. 1091–1104, 2013. DOI (I.F.: 1.943)More..


The main objective of remote substations is to provide the central system with sensitive information from critical infrastructures, such as generation, distribution or transmission power systems. Wireless sensor networks have been recently applied in this particular context due to their attractive services and inherent benefits, such as simplicity, reliability and cost savings. However, as the number of control and data acquisition systems that use the Internet infrastructure to connect to substations increases, it is necessary to consider what connectivity model the sensor infrastructure should follow: either completely isolated from the Internet or integrated with it as part of the Internet of Things paradigm. This paper therefore addresses this question by providing a thorough analysis of both security requirements and infrastructural requirements corresponding to all those TCP/IP integration strategies that can be applicable to networks with constrained computational resources.

Impact Factor: 1.943
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

PDF icon 1752.pdf (1.21 MB)
I. Agudo, J. Lopez, and J. A. Montenegro, "A Graphical Delegation Solution for X.509 Attribute Certificates",
ERCIM News, no. 63, ERCIM, pp. 33-34, October, 2005. More..
PDF icon IsaacAgudo2005.pdf (157.48 KB)
I. Agudo, "Digital Identity and Identity Management Technologies",
UPGRADE - The European Journal of the Informatics Professional, vol. 2010, CEPIS, pp. 6 - 12, 2010. More..


There are many technologies for identity management available in the form of open specifications, open source tools and commercial applications. Currently, there are some competing standards for identity management. At the beginning SAML was the only viable choice with a higher enough acceptance level. Recently, another technology called WS-Federation has also gain some attention from the community. Although this technology is not as mature as SAML, it modular design gives it some advantages over SAML. It this work we mainly focus on the WS-Federation and the family of specifications that surround it.

PDF icon 1589.pdf (319.75 KB)
I. Agudo, M. Montenegro-Gómez, and J. Lopez, "A Blockchain Approach for Decentralized V2X (D-V2X)",
IEEE Transactions on Vehicular Technology, vol. 70, no. 5, IEEE, pp. 4001 - 4010, 05/2021. DOI (I.F.: 5.978)More..


New mobility paradigms have appeared in recent years, and everything suggests that some more are coming. This fact makes apparent the necessity of modernizing the road infrastructure, the signalling elements and the traffic management systems. Many initiatives have emerged around the term Intelligent Transport System (ITS) in order to define new scenarios and requirements for this kind of applications. We even have two main competing technologies for implementing Vehicular communication protocols (V2X), C-V2X and 802.11p, but neither of them is widely deployed yet.

One of the main barriers for the massive adoption of those technologies is governance. Current solutions rely on the use of a public key infrastructure that enables secure collaboration between the different entities in the V2X ecosystem, but given its global scope, managing such infrastructure requires reaching agreements between many parties, with conflicts of interest between automakers and telecommunication operators. As a result, there are plenty of use cases available and two mature communication technologies, but the complexity at the business layer is stopping the drivers from taking advantage of ITS applications.

Blockchain technologies are defining a new decentralized paradigm for most traditional applications, where smart contracts provide a straightforward mechanism for decentralized governance. In this work, we propose an approach for decentralized V2X (D-V2X) that does not require any trusted authority and can be implemented on top of any communication protocol. We also define a proof-of-concept technical architecture on top of a cheap and highly secure System-on-Chip (SoC) that could allow for massive adoption of D-V2X. 

Impact Factor: 5.978
Journal Citation Reports® Science Edition (Thomson Reuters, 2020)

PDF icon Agudo2020.pdf (245.4 KB)
I. Agudo, J. Lopez, and J. A. Montenegro, "Enabling Attribute Delegation in Ubiquitous Environments",
Mobile Networks and Applications, vol. 13, no. 3-4, Springer, pp. 398-410, August, 2008. DOI (I.F.: 1.619)More..


When delegation is implemented using the attribute certificates in a Privilege Management Infrastructure (PMI), it is possible to reach a considerable level of distributed functionality. However, the approach is not flexible enough for the requirements of ubiquitous environments. The PMI can become a too complex solution for devices such as smartphones and PDAs, where resources are limited. In this work we present an approach to solve the previous limitations by defining a second class of attributes, called domain attributes, which are managed directly by users and are not right under the scope of the PMI, thus providing a light solution for constrained devices. However, we relate the two classes of attributes are related by defining a simple ontology. While domain attribute credentials are defined using SAML notation, global attributes are defined using X.509 certificates. For this reason, we additionally introduce XSAML so that both kinds of credentials are integrated. We also introduce the concept of Attribute Federation which is responsible for supporting domain attributes and the corresponding ontology.

Impact Factor: 1.619
Journal Citation Reports® Science Edition (Thomson Reuters, 2008)

PDF icon Agudo2008d.pdf (647.04 KB)
I. Agudo, R. Rios, and J. Lopez, "A Privacy-Aware Continuous Authentication Scheme for Proximity-Based Access Control",
Computers & Security, vol. 39 (B), Elsevier, pp. 117-126, 11/2013. DOI (I.F.: 1.172)More..


Continuous authentication is mainly associated with the use of biometrics to guarantee that a resource is being accessed by the same user throughout the usage period. Wireless devices can also serve as a supporting technology for continuous authentication or even as a complete alternative to biometrics when accessing proximity-based services. In this paper we present the implementation of a secure, non-invasive continuous authentication scheme supported by the use of Wearable Wireless Devices (WWD), which allow users to gain access to proximity-based services while preserving their privacy. Additionally we devise an improved scheme that circumvents some of the limitations of our implementation.

Impact Factor: 1.172
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

PDF icon agudo2013.pdf (436.44 KB)
I. Agudo, C. Fernandez-Gago, and J. Lopez, "A Scale Based Trust Model for Multi-Context Environments",
Computers and Mathematics with Applications, vol. 60, Elsevier, pp. 209-216, July, 2010. DOI (I.F.: 1.472)More..


When interactions among users of a system have to take place, for example, over the internet, establishing trust relationships among these users becomes crucial. However, the way this trust is established depends to a certain extent on the context where the interactions take place. Most of the time, trust is encoded as a numerical value that might not be very meaningful for a not very experienced user. In this paper we propose a model that takes into account the semantic and the computational sides of trust. This avoids users having to deal directly with the computational side; they instead deal with meaningful labels such as Bad or Good in a given context.

Impact Factor: 1.472
Journal Citation Reports® Science Edition (Thomson Reuters, 2010)

PDF icon Agudo2010b.pdf (279.77 KB)
I. Agudo, C. Fernandez-Gago, and J. Lopez, "Concurrent access control for multi-user and multi-processor systems based on trust relationships",
Concurrency and Computation: Practice and Experience, vol. 21, John Wiley & Sons, pp. 1389-1403, July, 2009. DOI (I.F.: 1.004)More..


Concurrent access control is an old problem in many fields in Computer Science. It has been solved in many languages and systems, using mechanisms like monitors or priority queues. Nowadays computers implement multi-core capabilities. This means that they are virtually capable of execution of processes in parallel. This requires new techniques and open new issues in the field of concurrent access control. Moreover, most operating systems are multi-user; thus, we have to focus on a multi-processor multi-user scenario. Trust becomes a paramount aspect when building distributed applications; the same applies on a lower scale in modern computers. We propose the use of a trust graph that keeps record of the trust relationships of the system and helps in deciding on concurrent access requests. The information encoded in the graph will be used both in order to decide on the access requests and to order granted requests in terms of their associated trust level

Impact Factor: 1.004
Journal Citation Reports® Science Edition (Thomson Reuters, 2009)

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S. Agrawal, M. Lal Das, and J. Lopez, "Detection of Node Capture Attack in Wireless Sensor Networks",
IEEE Systems Journal, vol. 13, issue 1, IEEE, pp. 238 - 247, 03/2019. (I.F.: 3.987)More..
Impact Factor: 3.987
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)