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S. Russell, E. Okamoto, E. Dawson, and J. Lopez, "Improving Performance in Global PKI using Virtual Certificates and Synthetic Certificates",
Symposium on Cryptography and Information Security (SCIS’02), pp. 1149-1154, January, 2002. More..

Abstract

A digital certificate may be used to inform the world of the public key of its owner. To guard against impersonations and fraud, the receiver needs to perform a series of checks. When a hierarchy of certificates is involved, and when there are large volumes of messages between two parties, as is frequent in commerce, the repeated validation of the same chain of certificates consume significant resources. This paper presents new concepts of virtual certificate and synthetic certificate which can be used to speed up repetitive processing of a chain with improved efficiency.

PDF icon SelwynRussell2002.pdf (182.25 KB)
S. Rusell, E. Dawson, E. Okamoto, and J. Lopez, "Virtual Certificates and Synthetic Certificates: New Paradigms for Improving Public Key Validation",
Computer Communications, vol. 26, no. 16, Elsevier, pp. 1826-1838, 2003. (I.F.: 0.508)More..

Abstract

The certificate paradigm is applied recursively to obtain the public keys of a number of Certification Authorities and, accordingly, to obtain the public keys of a number of final entities. Thus, validation of the authorized public key of a party in a network transaction is commonly based on processing the certificate chain descended from a trusted root issuer, involving non-negligible time and cost. Those chains become long in communications between large organizations, which is the typical case of e-commerce and e-government applications. The process of validation of extensive chains introduces performance problems in two aspects: signature verification and revocation checking. That is, the repeated processing of long chains of certificates creates severe efficiency problems. This fact causes that most of the advantages provided by Public Key Infrastructures (PKIs) are not conveniently exploited. In this paper we analyze the scenarios in which large volumes of digitally signed transactions between commercial entities exist. These cases require of interoperation among PKIs. We show that solutions available in those scenarios still involve processing of too long chains of certificates, either at the receiving computer or by an outsourced entity. For this reason, we propose new concepts of virtual certificate and synthetic certificate for faster and less costly processing of certificate chains. In this way, communications in a certificate-based intercommunity can be highly improved. We also show how these types of certificates can be applied in practice.

Impact Factor: 0.508
Journal Citation Reports® Science Edition (Thomson Reuters, 2003)

PDF icon SelwynRusell2003.pdf (227.92 KB)
J. E. Rubio, R. Roman, C. Alcaraz, and Y. Zhang, "Tracking Advanced Persistent Threats in Critical Infrastructures through Opinion Dynamics",
European Symposium on Research in Computer Security (ESORICS 2018), vol. 11098, Springer, pp. 555-574, 08/2018. DOI More..

Abstract

Advanced persistent threats pose a serious issue for modern industrial environments, due to their targeted and complex attack vectors that are difficult to detect. This is especially severe in critical infrastructures that are accelerating the integration of IT technologies. It is then essential to further develop effective monitoring and response systems that ensure the continuity of business to face the arising set of cyber-security threats. In this paper, we study the practical applicability of a novel technique based on opinion dynamics, that permits to trace the attack throughout all its stages along the network by correlating different anomalies measured over time, thereby taking the persistence of threats and the criticality of resources into consideration. The resulting information is of essential importance to monitor the overall health of the control system and correspondingly deploy accurate response procedures.

PDF icon RubioRomanAlcarazZhang2018.pdf (1.21 MB)
J. E. Rubio, C. Alcaraz, and J. Lopez, "Preventing Advanced Persistent Threats in Complex Control Networks",
European Symposium on Research in Computer Security, vol. 10493, 22nd European Symposium on Research in Computer Security (ESORICS 2017), pp. 402-418, 09/2017. More..
PDF icon RubioAlcarazLopez2017ESORICS.pdf (955.81 KB)
J. E. Rubio, M. Manulis, C. Alcaraz, and J. Lopez, "Enhancing Security and Dependability of Industrial Networks with Opinion Dynamics",
European Symposium on Research in Computer Security (ESORICS2019), vol. 11736, pp. 263-280, 09/2019. DOI More..
PDF icon RubioESORICS2019.pdf (489.08 KB)
J. E. Rubio, C. Alcaraz, R. Roman, and J. Lopez, "Analysis of Intrusion Detection Systems in Industrial Ecosystems",
14th International Conference on Security and Cryptography (SECRYPT 2017), vol. 6, SciTePress, pp. 116-128, 2017. DOI More..
PDF icon 1662.pdf (312.9 KB)
J. E. Rubio, R. Roman, C. Alcaraz, and Y. Zhang, "Tracking APTs in Industrial Ecosystems: A Proof of Concept",
Journal of Computer Security, vol. 27, issue 5, Elsevier, pp. 521-546, 09/2019. (I.F.: 3.579)More..
Impact Factor: 3.579
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)

PDF icon RubioSIJCS19.pdf (3.26 MB)
J. E. Rubio, C. Alcaraz, and J. Lopez, "Addressing Security in OCPP: Protection Against Man-in-the-Middle Attacks",
9th IFIP International Conference on New Technologies, Mobility & Security, 2018. More..
PDF icon 1692.pdf (259.16 KB)
J. E. Rubio, C. Alcaraz, R. Rios, R. Roman, and J. Lopez, "Distributed Detection of APTs: Consensus vs. Clustering",
25th European Symposium on Research in Computer Security (ESORICS 2020), vol. 12308, pp. 174-192, 09/2020. DOI More..
PDF icon 1846.pdf (1.07 MB)
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..

Abstract

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)
J. E. Rubio, C. Alcaraz, R. Roman, and J. Lopez, "Current Cyber-Defense Trends in Industrial Control Systems",
Computers & Security Journal, vol. 87, Elsevier, 11/2019. DOI (I.F.: 3.579)More..

Abstract

Advanced Persistent Threats (APTs) have become a serious hazard for any critical infrastructure, as a single solution to protect all industrial assets from these complex attacks does not exist. It is then essential to understand what are the defense mechanisms that can be used as a first line of defense. For this purpose, this article will firstly study the spectrum of attack vectors that APTs can use against existing and novel elements of an industrial ecosystem. Afterwards, this article will provide an analysis of the evolution and applicability of Intrusion Detection Systems (IDS) that have been proposed in both the industry and academia.

Impact Factor: 3.579
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)

PDF icon rub2019cose.pdf (190.71 KB)
J. E. Rubio, C. Alcaraz, and J. Lopez, "Selecting Privacy Solutions to Prioritise Control in Smart Metering Systems",
The 11th International Conference on Critical Information Infrastructures Security, vol. 10242, pp. 176-188, 2017. More..

Abstract

The introduction of the Smart Grid brings with it several benefits to society, because its bi-directional communication allows both users and utilities to have better control over energy usage. However, it also has some privacy issues with respect to the privacy of the customers when analysing their consumption data. In this paper we review the main privacy-preserving techniques that have been proposed and compare their efficiency, to accurately select the most appropriate ones for undertaking control operations. Both privacy and performance are essential for the rapid adoption of Smart Grid technologies.

PDF icon 1600.pdf (275.75 KB)
J. E. Rubio, C. Alcaraz, and J. Lopez, "Game Theory-Based Approach for Defense against APTs",
18th International Conference on Applied Cryptography and Network Security (ACNS’20), vol. 12147, Springer, pp. 297-320, 10/2020. DOI
J. E. Rubio, R. Roman, and J. Lopez, "Analysis of cybersecurity threats in Industry 4.0: the case of intrusion detection",
The 12th International Conference on Critical Information Infrastructures Security, vol. Lecture Notes in Computer Science, vol 10707, Springer, pp. 119-130, 08/2018. More..
PDF icon 1666.pdf (236.18 KB)
J. E. Rubio, R. Roman, and J. Lopez, "Integration of a Threat Traceability Solution in the Industrial Internet of Things",
IEEE Transactions on Industrial Informatics, vol. 16, issue 10, no. 6575-6583, IEEE, 10/2020. DOI (I.F.: 9.112)More..

Abstract

In Industrial Internet of Things (IIoT) scenarios, where a plethora of IoT technologies coexist with consolidated industrial infrastructures, the integration of security mechanisms that provide protection against cyber-security attacks becomes a critical challenge. Due to the stealthy and persistent nature of some of these attacks, such as Advanced Persistent Threats, it is crucial to go beyond traditional Intrusion Detection Systems for the traceability of these attacks. In this sense, Opinion Dynamics poses a novel approach for the correlation of anomalies, which has been successfully applied to other network security domains. In this paper, we aim to analyze its applicability in the IIoT from a technical point of view, by studying its deployment over different IIoT architectures and defining a common framework for the acquisition of data considering the computational constraints involved. The result is a beneficial insight that demonstrates the feasibility of this approach when applied to upcoming IIoT infrastructures.

Impact Factor: 9.112
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)

PDF icon Rubio2020IIoT.pdf (2.13 MB)
D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "A Study of Security Approaches for the Development of Mobile Grid Systems",
5th International Conference on Software and Data Technologies (ICSOFT’10), vol. 1, Springer, pp. 133-138, july, 2010. More..

Abstract

Mobile Grid systems allow us to build highly complex information systems with various and remarkable features (interoperability between multiple security domains, cross-domain authentication and authorization, dynamic, heterogeneous and limited mobile devices, etc), which demand secure development methodologies to build quality software, offering methods, techniques and tools that facilitate the work of the entire team involved in software development. These methodologies should be supported by Grid security architectures that define the main security aspects to be considered, and by solutions to the problem of how to integrate mobile devices within Grid systems. Some approaches regarding secure development methodologies of Grid security architectures and of the integration of mobile devices in the Grid have been found in literature, and these are analyzed and studied in this paper, offering a comparison framework of all the approaches related to security in Mobile Grid environments.

D. G. Rosado, E.. Fernandez-Medina, and J. Lopez, "Security in the Developments Process of Mobile Grid Systems",
Advances in Grid Computing, Zoran Constantinescu, Intech, pp. 173-198, 2011. More..
PDF icon 1626.pdf (774.86 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "Engineering Process Based On Grid Use Cases For Mobile Grid Systems",
Third International Conference on Software and Data Technologies (ICSOFT’08), Springer, pp. 146-151, 2008. More..

Abstract

 

The interest to incorporate mobile devices into Grid systems has arisen with two main purposes. The firstone is to enrich users of these devices while the other is that of enriching the own Grid infrastructure.Security of these systems, due to their distributed and open nature, is considered a topic of great interest. Aformal approach to security in the software life cycle is essential to protect corporate resources. However,little attention has been paid to this aspect of software development. Due to its criticality, security should beintegrated as a formal approach into the software life cycle. We are developing a methodology ofdevelopment for secure mobile Grid computing based systems that helps to design and build secure Gridsystems with support for mobile devices directed by use cases and security use cases and focused onservice-oriented security architecture. In this paper, we will present one of the first steps of ourmethodology consisting of analyzing security requirements of mobile grid systems. This analysis will allowus to obtain a set of security requirements that our methodology must cover and implement.

 

 

PDF icon rosado2008a.pdf (813.44 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "Towards a UML Extension of Reusable Secure Use Cases for Mobile Grid systems",
IEICE Trans. on Information and Systems, vol. E94-D, IEICE, pp. 243-254, Feb 2011. DOI (I.F.: 0.178)More..

Abstract

The systematic processes exactly define the development cycle and help the development team follow the same development strategies and techniques, thus allowing a continuous improvement in the quality of the developed products. Likewise, it is important that the development process used integrates security aspects from the first stages at the same level as other functional and non-functional requirements. Grid systems allow us to build very complex information systems with different and remarkable features (interoperability between multiple security domains, cross-domain authentication and authorization, dynamic, heterogeneous and limited mobile devices, etc). With the development of wireless technology and mobile devices, the Grid becomes the perfect candidate for letting mobile users make complex works that add new computational capacity to the Grid. A methodology of development for secure mobile Grid systems is being defined. One of the activities of this methodology is the requirements analysis which is based in reusable use cases. In this paper, we will present a UML-extension for security use cases and Grid use case which capture the behaviour of this kind of systems. A detailed description of all these new use cases defined in the UML extension is necessary, describing the stereotypes, tagged values, constraints and graphical notation. We show an example of how to apply and use this extension for building the diagram of use cases and incorporating common security aspects for this kind of systems. Also, we will see how the diagrams built can be reused in the construction of others diagrams saving time and effort in this task.
 

Impact Factor: 0.178
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon rosado2009.pdf (302.25 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "Analysis of Secure Mobile Grid Systems: A Systematic Approach",
Information and Software Technology, vol. 52, Elsevier, pp. 517-536, May 2010. DOI (I.F.: 1.527)More..

Abstract

Developing software through systematic processes is becoming more and more important due to the growing complexity of software development. It is important that the development process used integrates security aspects from the first stages at the same level as other functional and non-functional requirements. Systems which are based on Grid Computing are a kind of systems that have clear differentiating features in which security is a highly important aspect. The Mobile Grid, which is relevant to both Grid and Mobile Computing, is a full inheritor of the Grid with the additional feature that it supports mobile users and resources. A development methodology for Secure Mobile Grid Systems is proposed in which the security aspects are considered from the first stages of the life-cycle and in which the mobile Grid technological environment is always present in each activity. This paper presents the analysis activity, in which the requirements (focusing on the grid, mobile and security requirements) of the system are specified and which is driven by reusable use cases through which the requirements and needs of these systems can be defined. These use cases have been defined through a UML-extension for security use cases and Grid use cases which capture the behaviour of this kind of systems. The analysis activity has been applied to a real case.

Impact Factor: 1.527
Journal Citation Reports® Science Edition (Thomson Reuters, 2010)

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..

Abstract

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.

 

D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Obtaining Security Requirements for a Mobile Grid System",
International Journal of Grid and High Performance Computing, vol. 1, IGI-Global, pp. 1-17, Jan 2009. DOI More..

Abstract

Mobile Grid includes the characteristics of the Grid systems together with the peculiarities of Mobile Computing, withthe additional feature of supporting mobile users and resources ina seamless, transparent, secure and efficient way. Security ofthese systems, due to their distributed and open nature, isconsidered a topic of great interest. We are elaborating amethodology of development to build secure mobile grid systemsconsidering security on all life cycle. In this paper we present thepractical results applying our methodology to a real case,specifically we apply the part of security requirements analysis toobtain and identify security requirements of a specific applicationfollowing a set of tasks defined for helping us in the definition,identification and specification of the security requirements onour case study. The methodology will help us to build a securegrid application in a systematic and iterative way.

PDF icon rosado2009c.pdf (219.29 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "Developing a Secure Mobile Grid System through a UML Extension",
Journal of Universal Computer Science, vol. 16, no. 17, Springer, pp. 2333-2352, Sep 2010. DOI (I.F.: 0.578)More..

Abstract

The idea of developing software through systematic development processes toimprove software quality is not new. Nevertheless, there are still many information systemssuch as those of Grid Computing which are not developed through methodologies that areadapted to their most differentiating features. A systematic development process for Gridsystems that supports the participation of mobile nodes and incorporates security aspects intothe entire software lifecycle will thus play a significant role in the development of systemsbased on Grid computing. We are creating a development process for the construction ofinformation systems based on Grid Computing, which is highly dependent on mobile devices,in which security plays a highly important role. One of the activities in this process is that ofanalysis which is focused on ensuring that the system’s security and functional requirements areelicited, specified and modelled. In our approach, this activity is driven by use cases andsupported by the reusable repository. This obtains, builds, defines and refines the use cases ofthe secure Mobile Grid systems which represent the functional and non-functional requirementsof this kind of systems. In this paper, we present the proposed development process throughwhich we introduce the main aspects of the UML profile defined for building use case diagramsin the mobile Grid context through which it is possible to represent specific mobile Gridfeatures and security aspects, showing in detail how to build use case diagrams for a real mobile Grid application by using our UML profile, denominated as GridUCSec-Profile.

Impact Factor: 0.578
Journal Citation Reports® Science Edition (Thomson Reuters, 2010)

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..

Abstract

 

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, J. Lopez, and M. Piattini, "Systematic Design of Secure Mobile Grid Systems",
Journal of Network and Computer Applications, vol. 34, Elsevier, pp. 1168-1183, 2011. (I.F.: 1.065)More..

Abstract

 Grid computing has arisen as an evolution of distributed systems mainly focused on the sharing of and remote access to resources in a uniform, transparent, secure, efficient and reliable manner. It is possible to join Grid technology and mobile technology in order to create one of the most promising technologies and developments to appear in recent years, in that they enrich one another and provide new solutions that solve many of the limitations and problems found in different technologies. Security is a very important factor in Mobile Grid Computing and is also difficult to achieve owing to the open nature of wireless networks and heterogeneous and distributed environments. Success in obtaining a secure system originates in incorporating security from the first stages of the development process. It has therefore been necessary to define a development process for this kind of systems in which security is incorporated in all stages of the development and the features and particularities of the Mobile Grid systems are taken into consideration. This paper presents one of the activities of this development process, the design activity, which consists of defining and designing a security software architecture. This architecture will be built from a security architecture, defined as reference architecture, in which security services, interfaces and operations are defined with the purpose of defining a reference security architecture which covers the majority of security requirements identified in the analysis activity. The design activity will build the system architecture that will be the input artefact for the subsequent activity in the process, which is the construction activity.

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

D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Hacia una Arquitectura de Servicios de Seguridad para entornos Grid móviles",
V Congreso Iberoamericano de Seguridad Informática (CIBSI’09), Universidad de la República, Uruguay, pp. 409-423, 2009. More..

Abstract

 

Grid móvil incluye las características de los sistemas Grid junto conlas peculiaridades de la computación móvil, añadiendo la propiedad de soportarusuarios y recursos móviles de forma homogénea, transparente, segura yeficiente. La seguridad de estos sistemas, debido a su naturaleza abierta ydistribuida, es un tema de gran interés. Una arquitectura de seguridad basada enSOA proporciona una arquitectura distribuida diseñada para interoperabilidadde servicios, fácil integración, y acceso seguro, simple y extensible. Por tanto,una arquitectura orientada a servicios de seguridad es construida para entornosGrid móviles, ofreciendo servicios de seguridad a usuarios móviles quienesusan servicios Grid y recursos para ejecutar sus trabajos y tareas. Estaarquitectura es integrada con otras arquitecturas existentes proporcionandomayor seguridad y permitiendo que los usuarios móviles puedan acceder aservicios Grid existentes ofreciendo nuevos y necesarios servicios de seguridadpara Grid móviles. Hemos definido un conjunto de servicios de seguridad, quejunto a protocolos, políticas y estándares de seguridad forman una arquitecturade seguridad orientada a servicios para entornos Grid móviles. Esta arquitecturaes abierta, escalable, dinámica, interoperable y flexible.

 

 

PDF icon rosado2009d.pdf (314.97 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "PSecGCM: Process for the development of Secure Grid Computing based Systems with Mobile devices",
International Conference on Availability, Reliability and Security (ARES’08), IEEE Computer Society, pp. 136-143, 2008. More..

Abstract

 

A Grid computing system is defined as a platformthat supports distributed system applications which require fastaccess to a large quantity of distributed resources in acoordinated manner. With the development of wirelesstechnology and mobile devices, the Grid becomes the perfectcandidate so that mobile users can make complex works that addnew computational capacity to the Grid. Security of thesesystems, due to their distributed and open nature, receives greatinterest. The growing size and profile of the grid requirecomprehensive security solutions as they are critical to thesuccess of the endeavour. A formal approach to security in thesoftware life cycle is essential to protect corporate resources.However, little thought has been given to this aspect of softwaredevelopment. Due to its criticality, security should be integratedas a formal approach in the software life cycle. A methodology ofdevelopment for secure mobile Grid computing based systems isdefined, that is to say, an engineering process that defines thesteps to follow so that starting from the necessities to solve, wecan design and construct a secure Grid system with support formobile devices that is able to solve and cover these necessities.

 

 

PDF icon rosado2008.pdf (164.18 KB)
D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Security Services Architecture for Secure Mobile Grid Systems",
Journal of Systems Architecture, vol. 57, Elsevier, pp. 240-258, 2011. (I.F.: 0.444)More..

Abstract

 Mobile Grid, is a full inheritor of the Grid with the additional feature that it supports mobile users andresources. Security is an important aspect in Grid based systems, and it is more complex to ensure thisin a mobile platform owing to the limitations of resources in these devices. A Grid infrastructure that supportsthe participation of mobile nodes and incorporates security aspects will thus play a significant rolein the development of Grid computing. The idea of developing software through systematic developmentprocesses to improve software quality is not new. However, many information systems such as those ofGrid Computing are still not developed through methodologies which have been adapted to their mostdifferentiating features. The lack of adequate development methods for this kind of systems in whichsecurity is taken into account has encouraged us to build a methodology to develop them, offering adetailed guide for their analysis, design and implementation. It is important to use software V&V techniques,according to IEEE Std. 1012 for Software Verification and Validation, to ensure that a software systemmeets the operational needs of the user. This ensures that the requirements for the system arecorrect, complete, and consistent, and that the life-cycle products correctly design and implement systemrequirements. This paper shows part of a development process that we are elaborating for the constructionof information systems based on Grid Computing, which are highly dependent on mobile devices inwhich security plays a highly important role. In the design activity of the process, we design a securityarchitecture which serves as a reference for any mobile Grid application that we wish to build since thissecurity architecture defines a complete set of security services which will be instantiated depending onthe requirements and features found in previous activities of the process. A V&V task is also defined in thedesign activity to validate and verify both the architecture built and the traceability of the artifacts generatedin this activity. In this paper, we will present the service-oriented security architecture for MobileGrid Systems which considers all possible security services that may be required for any mobile Grid application.

Impact Factor: 0.444
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Extensión UML para Casos de Uso Reutilizables en entornos Grid Móviles Seguros",
XIV Jornadas de Ingeniería del Software y Bases de Datos (JISBD 2009), Antonio Vallecillo and Goiuria Sagardui (Eds.), pp. 331-342, September, 2009. More..

Abstract

 

 

 

Los sistemas Grid nos permiten construir sistemas complejos concaracterísticas diferenciadoras (interoperabilidad entre múltiples dominios deseguridad, autenticación y autorización a través de dominios, sistema dinámicoy heterogéneo, etc.). Con el desarrollo de la tecnología wireless y losdispositivos móviles, el Grid llega a ser el candidato perfecto para que losusuarios móviles puedan realizar trabajos complejos, a la vez que añaden nuevacapacidad computacional al Grid. Estamos construyendo un proceso completode desarrollo para sistemas Grid móviles seguros, y una de las actividades es elanálisis de requisitos, que está basado en casos de uso reutilizables. En esteartículo, presentaremos una extensión UML para casos de uso de seguridad yGrid, los cuales capturan el comportamiento de este tipo de sistemas. Estaextensión UML está siendo aplicado a un caso real para construir diagramas decasos de uso de la aplicación, incorporando los aspectos de seguridadnecesarios.

PDF icon rosado2009e.pdf (372.27 KB)
D. G. Rosado, E. Fernandez-Medina, J. Lopez, and M. Piattini, "Hacia un Proceso sistemático para el desarrollo de sistemas Grid Seguros con Dispositivos Móviles",
IV Congreso Iberoamericano de Seguridad Informática (CIBSI’07), Sebastián Cañón, M.A., pp. 111-124, 2007.
D. G. Rosado, E. Fernandez-Medina, and J. Lopez, "Applying a UML Extension to build Use Cases diagrams in a secure mobile Grid application",
5th International Workshop on Foundations and Practices of UML, LNCS 5833, Springer Berlin Heidelberg, pp. 126-136, 2009. More..

Abstract

 

Systems based on Grid computing have not traditionally beendeveloped through suitable methodologies and have not taken into accountsecurity requirements throughout their development, offering technical securitysolutions only during the implementation stages. We are creating a developmentmethodology for the construction of information systems based on GridComputing, which is highly dependent on mobile devices, in which securityplays a highly important role. One of the activities in this methodology is therequirements analysis which is use-case driven. In this paper, we build use casediagrams for a real mobile Grid application by using a UML-extension, calledGridUCSec-Profile, through which it is possible to represent specific mobileGrid features and security aspects for use case diagrams, thus obtainingdiagrams for secure mobile Grid environments.

 

 

PDF icon rosado2009f.pdf (249 KB)
D. G. Rosado, E.. Fernandez-Medina, M.. Pattini, and J. Lopez, "Analysis of Secure Mobile Grid Systems: A systematic approach",
XVI Jornadas de Ingeniería del Software y Bases de Datos (JISBD 2011), Servizo de publicacións da Universidade da Coruña, pp. 487-491, 2011. More..

Abstract

Developing software through systematic processes is becoming more and more important due to the growing complexity of software development. It is important that the development process used integrates security aspects from the first stages at the same level as other functional and non-functional requirements. The identification of security aspects in the first stages ensures a more robust development and permits the security requirements to be perfectly coupled with the design and the rest of the system’s requirements. Systems which are based on Grid Computing are a kind of systems that have clear differentiating features in which security is a highly important aspect. Generic development processes are sometimes used to develop Grid specific systems without taking into consideration either the subjacent technological environment or the special features and particularities of these specific systems. In fact, the majority of existing Grid applications have been built without a systematic development process and are based on ad hoc developments.

PDF icon 1642.pdf (44.27 KB)
R. Roman, C. Fernandez-Gago, J. Lopez, and H. Hwa Chen, "Trust and Reputation Systems for Wireless Sensor Networks",
Security and Privacy in Mobile and Wireless Networking, S. Gritzalis, T. Karygiannis, and C. Skianis Eds., Troubador Publishing Ltd, pp. 105-128, 2009. More..

Abstract

The concept of trust has become very relevant in the late years as a consequence of the growth of fields such as internet transactions or electronic commerce. In general, trust has become of paramount importance for any kind of distributed networks, such as wireless sensor networks (WSN in the following). In this chapter of the book, we try to give a general overview of the state of the art on trust management systems for WSN and also try to identify the main features of the architectures of these trust management systems.

PDF icon Roman2009b.pdf (291.67 KB)
R. Roman, P. Najera, and J. Lopez, "Securing the Internet of Things",
IEEE Computer, vol. 44, no. 9, IEEE, pp. 51 -58, Sept 2011. DOI (I.F.: 1.47)More..

Abstract

This paper presents security of Internet of things. In the Internet of Things vision, every physical object has a virtual component that can produce and consume services Such extreme interconnection will bring unprecedented convenience and economy, but it will also require novel approaches to ensure its safe and ethical use. The Internet and its users are already under continual attack, and a growing economy-replete with business models that undermine the Internet’s ethical use-is fully focused on exploiting the current version’s foundational weaknesses.

Impact Factor: 1.47
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon 1633.pdf (373.78 KB)
R. Roman, C. Alcaraz, and J. Lopez, "A Survey of Cryptographic Primitives and Implementations for Hardware-Constrained Sensor Network Nodes",
Mobile Networks and Applications, vol. 12, no. 4, Springer, pp. 231-244, August, 2007. DOI (I.F.: 0.586)More..

Abstract

In a wireless sensor network environment, a sensor node is extremely constrained in terms of hardware due to factors such as maximizing lifetime and minimizing physical size and overall cost. Nevertheless, these nodes must be able to run cryptographic operations based on primitives such as hash functions, symmetric encryption and public key cryptography in order to allow the creation of secure services. Our objective in this paper is to survey how the existing research-based and commercial-based sensor nodes are suitable for this purpose, analyzing how the hardware can influence the provision of the primitives and how software implementations tackles the task of implementing instances of those primitives. As a result, it will be possible to evaluate the influence of provision of security in the protocols and applications/scenarios where sensors can be used.

Impact Factor: 0.586
Journal Citation Reports® Science Edition (Thomson Reuters, 2007)

PDF icon Roman2007.pdf (280.7 KB)
R. Roman, J. Zhou, and J. Lopez, "Protection Against Spam using Pre-Challenges",
20th IFIP International Information Security Conference (IFIP-SEC’05), R. Sasaki, S. Qing, E. Okamoto, and H. Yoshiura Eds., Springer, pp. 281-294, May, 2005. More..

Abstract

Spam turns out to be an increasingly serious problem to email users. A number of anti-spam schemes have been proposed and deployed, but the problem has yet been well addressed. One of those schemes is challenge-response, in which a challenge is imposed on an email sender. However, such a scheme introduces new problems for the users, e.g., delay of service and denial of service attacks. In this paper, we introduce a pre-challenge scheme that avoids those problems. It assumes each user has a challenge that is defined by the user himself/herself and associated with his/her email address, in such a way that an email sender can simultaneously retrieve a new receiver’s email address and challenge before sending an email in the first contact. Some new mechanisms are employed to reach a good balance between security against spam and convenience to email users.

PDF icon Roman2005d.pdf (174.76 KB)
R. Roman, J. Lopez, and C. Alcaraz, "Do Wireless Sensor Networks Need to be Completely Integrated into the Internet?",
3rd CompanionAble Workshop - Future Internet of People, Things and Services (IoPTS) eco-Systems, xxxx, pp. xxxx, December, 2009. More..

Abstract

Wireless sensor networks are considered as an integral part of the Internet of Things paradigm. Not only they provide a virtual presence to elements of the real world, but also allow any computationalsystem to know about the physical state of those elements thanks to the use of embedded sensors. In order to belong to the Internet of Things, the elements of a sensor network can implement Internet protocols and services such as the TCP/IP stack and web services. Still, a question that must be raised at this point of time is whether all sensor network applications should be completely integrated into the Internet or not. The purpose of this paper is to analyze this question, reviewing the challenges and security requirements of Internet-enabled sensor networks.

PDF icon roman2009.pdf (106.88 KB)
R. Roman, J. Zhou, and J. Lopez, "An Anti-spam Scheme Using Pre-challenges",
Computer Communications, vol. 29, no. 15, Elsevier, pp. 2739-2749, 2006. DOI (I.F.: 0.444)More..

Abstract

Unsolicited Commercial Email, or Spam, is nowadays an increasingly serious problem to email users. A number of anti-spam schemes have been proposed in the literature and some of them have been deployed in email systems, but the problem has yet been well addressed. One of those schemes is challenge-response, in which a challenge, ranging from a simple mathematical problem to a hard-AI problem, is imposed on an email sender in order to forbid machine-based spam reaching receivers’ mailboxes. However, such a scheme introduces new problems for the users, e.g., delay of service and denial of service. In this paper, we introduce the pre-challenge scheme, which is based on the challenge-response mechanism and takes advantage of some features of email systems. It assumes each user has a challenge that is defined by the user himself/herself and associated with his/her email address, in such a way that an email sender can simultaneously retrieve a new receiver’s email address and challenge before sending an email in the first contact. Some new mechanisms are employed in our scheme to reach a good balance between security against spam and convenience to normal email users. Our scheme can be also used for protecting other messaging systems, like Instant Messaging and Blog comments.

Impact Factor: 0.444
Journal Citation Reports® Science Edition (Thomson Reuters, 2006)

PDF icon Roman2006a.pdf (355.8 KB)
R. Roman, J. Lopez, and M. Mambo, "Mobile edge computing, Fog et al.: A survey and analysis of security threats and challenges",
Future Generation Computer Systems, vol. 78, issue 1, Elsevier, pp. 680-698, 01/2018. DOI (I.F.: 5.768)More..

Abstract

For various reasons, the cloud computing paradigm is unable to meet certain requirements (e.g. low latency and jitter, context awareness, mobility support) that are crucial for several applications (e.g. vehicular networks, augmented reality). To fulfil these requirements, various paradigms, such as fog computing, mobile edge computing, and mobile cloud computing, have emerged in recent years. While these edge paradigms share several features, most of the existing research is compartmentalised; no synergies have been explored. This is especially true in the field of security, where most analyses focus only on one edge paradigm, while ignoring the others. The main goal of this study is to holistically analyse the security threats, challenges, and mechanisms inherent in all edge paradigms, while highlighting potential synergies and venues of collaboration. In our results, we will show that all edge paradigms should consider the advances in other paradigms.

Impact Factor: 5.768
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

PDF icon RomanFog16.pdf (775.54 KB)
R. Roman, J. Lopez, and S. Gritzalis, "Evolution and Trends in the Security of the Internet of Things",
IEEE Computer, vol. 51, issue 7, IEEE Computer Society, pp. 16-25, 07/2018. DOI (I.F.: 3.564)More..
Impact Factor: 3.564
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

R. Roman, and C. Alcaraz, "Applicability of Public Key Infrastructures in Wireless Sensor Networks",
European PKI Workshop: Theory and Practice (EuroPKI’07), LNCS 4582, Springer, pp. 313-320, June, 2007. DOI More..

Abstract

Wireless Sensor Networks (WSN) are becoming a key technology in the support of pervasive and ubiquitous services. The previous notion of PKC is too expensive for WSN has changed partially due to the existence of new hardware and software prototypes based on Elliptic Curve Cryptography and other PKC primitives. Then, it is necessary to analyze whether it is both feasible and convenient to have a Public Key Infrastructure for sensor networks that would allow the creation of PKC-based services like Digital Signatures.

PDF icon Roman2007b.pdf (142.01 KB)
R. Roman, J. Lopez, and P. Najera, "A Cross-layer Approach for Integrating Security Mechanisms in Sensor Networks Architectures",
Wireless Communications and Mobile Computing, vol. 11, Wiley, pp. 267-276, 2011. DOI (I.F.: 0.884)More..

Abstract

The wireless sensor networks (WSN) paradigm is especially vulnerable against external and internal attacks. Therefore, it is necessary to develop security mechanisms and protocols to protect them. These mechanisms must become an integral part of the software architecture and network stack of a sensor node. A question that remains is how to achieve this integration. In this paper we check how both academic and industrial solutions tackle this issue, and we present the concept of a transversal layer, where all the different security mechanisms could be contained. This way, all the elements of the architecture can interact with the security mechanisms, and the security mechanisms can have a holistic point of view of the whole architecture. We discuss the advantages of this approach, and also present how the transversal layer concept was applied to a real middleware architecture.

Impact Factor: 0.884
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon Roman2010.pdf (243.44 KB)
R. Roman, J. Zhou, and J. Lopez, "On the Security of Wireless Sensor Networks",
Computational Science and Its Applications (ICCSA’05), LNCS 3482, Springer, pp. 681-690, May, 2005. DOI More..

Abstract

Wireless Sensor Networks are extremely vulnerable against any kind of internal or external attacks, due to several factors such as resource-constrained nodes and lack of tamper-resistant packages. As a result, security must be an important factor to have in mind when designing the infrastructure and protocols of sensor networks. In this paper we survey the state-of-the-art security issues in sensor networks and highlight the open areas of research.security issues in sensor networks and highlight the open areas of research.

PDF icon Roman2005e.pdf (111.92 KB)
R. Roman, J. Zhou, and J. Lopez, "On the features and challenges of security and privacy in distributed internet of things",
Computer Networks, vol. 57, Elsevier, pp. 2266–2279, July 2013. DOI (I.F.: 1.282)More..

Abstract

In the Internet of Things, services can be provisioned using centralized architectures, where central entities acquire, process, and provide information. Alternatively, distributed architectures, where entities at the edge of the network exchange information and collaborate with each other in a dynamic way, can also be used. In order to understand the applicability and viability of this distributed approach, it is necessary to know its advantages and disadvantages – not only in terms of features but also in terms of security and privacy challenges. The purpose of this paper is to show that the distributed approach has various challenges that need to be solved, but also various interesting properties and strengths.

Impact Factor: 1.282
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

PDF icon roman2013iot.pdf (407.59 KB)
R. Roman, J. Lopez, and S. Gritzalis, "Situation Awareness Mechanisms for Wireless Sensor Networks",
IEEE Communications Magazine, vol. 46, no. 4, IEEE, pp. 102-107, April, 2008. DOI (I.F.: 2.799)More..

Abstract

A wireless sensor network should be able to operate for long periods of time with little or no external management. There is a requirement for this autonomy: the sensor nodes must be able to configure themselves in the presence of adverse situations. Therefore, the nodes should make use of situation awareness mechanisms to determine the existence of abnormal events in their surroundings. This work approaches the problem by considering the possible abnormal events as diseases, thus making it possible to diagnose them through their symptoms, namely, their side effects. Considering these awareness mechanisms as a foundation for high-level monitoring services, this article also shows how these mechanisms are included in the blueprint of an intrusion detection system.

Impact Factor: 2.799
Journal Citation Reports® Science Edition (Thomson Reuters, 2008)

PDF icon Roman2008a.pdf (280.63 KB)
R. Roman, C. Alcaraz, J. Lopez, and N. Sklavos, "Key management systems for sensor networks in the context of the Internet of Things",
Computers & Electrical Engineering, vol. 37, Elsevier, pp. 147-159, Mar 2011. DOI (I.F.: 0.837)More..

Abstract

If a wireless sensor network (WSN) is to be completely integrated into the Internet as part of the Internet of Things (IoT), it is necessary to consider various security challenges, such as the creation of a secure channel between an Internet host and a sensor node. In order to create such a channel, it is necessary to provide key management mechanisms that allow two remote devices to negotiate certain security credentials (e.g. secret keys) that will be used to protect the information flow. In this paper we will analyse not only the applicability of existing mechanisms such as public key cryptography and pre-shared keys for sensor nodes in the IoT context, but also the applicability of those link-layer oriented key management systems (KMS) whose original purpose is to provide shared keys for sensor nodes belonging to the same WSN.

Impact Factor: 0.837
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon roman2011.pdf (586.42 KB)
R. Roman, J. Zhou, and J. Lopez, "Applying Intrusion Detection Systems to Wireless Sensor Networks",
IEEE Consumer Communications & Networking Conference (CCNC 2006), IEEE, pp. 640-644, January, 2006. DOI More..

Abstract

The research of Intrusion Detection Systems (IDS) is a mature area in wired networks, and has also attracted many attentions in wireless ad hoc networks recently. Nevertheless, there is no previous work reported in the literature about IDS architectures in wireless sensor networks. In this paper, we discuss the general guidelines for applying IDS to static sensor networks, and introduce a novel technique to optimally watch over the communications of the sensors’ neighborhood on certain scenarios.

PDF icon Roman2006.pdf (144.74 KB)
R. Roman, et al., "Advanced Secure Multimedia Services for Digital Homes",
Information Systems Frontiers, vol. 14, Springer, pp. 527-540, July 2012. DOI (I.F.: 0.851)More..

Abstract

Our society is becoming increasingly more IT-oriented, and the images and sounds that reflect our daily life are being stored mainly in a digital form. This digital personal life can be part of the home multimedia contents, and users demand access and possibly share these contents (such as photographs, videos, and music) in an ubiquitous way: from any location and with any device. The purpose of this article is twofold. First, we introduce the Feel@Home system, whose main objective is to enable the previously mentioned vision of an ubiquitous digital personal life. Second, we describe the security architecture of Feel@Home, analyzing the security and privacy requirements that identify which threats and vulnerabilities must be considered, and deriving the security building blocks that can be used to protect both IMS-based and VPN-based solutions.

Impact Factor: 0.851
Journal Citation Reports® Science Edition (Thomson Reuters, 2012)

PDF icon Roman2010a.pdf (1.36 MB)
R. Roman, C. Fernandez-Gago, and J. Lopez, "Featuring Trust and Reputation Management Systems for Constrained Hardware Devices",
1st International Conference on Autonomic Computing and Communication Systems (Autonomics’07), ICST, October, 2007. More..

Abstract

Research on trust management systems for wireless sensor networks is still at a very early stage and few works have done so far. It seems that for those works which deal with the topic general features of how these systems should be are not clearly identified. In this paper we try to identify the main features that a trust management system should have and justify their importance for future developments.

PDF icon Roman2007c.pdf (110.26 KB)
R. Roman, J. Lopez, and J. Zhou, "Protección contra el Spam Utilizando Desafíos a Priori",
V Jornadas de Ingeniería Telemática (JITEL’05), pp. 375-382, September, 2005. More..

Abstract

Spam is considered to be one of the biggest problems in messaging systems. In the area of email Spam, A high number of anti-spam schemes have been proposed and deployed, but the problem has yet been well addressed. In this paper, we introduce a new scheme, called pre-challenge scheme, which avoids problems that exists in other schemes such as delay of service and denial of service. Some new mechanisms are employed to reach a good balance between security against Spam and convenience to email users. In addition, our scheme can be used for protecting other types of messaging systems, such as Instant Messaging (IM) and Blogs, against Spam.

PDF icon Roman2005a.pdf (280.64 KB)
R. Roman, and J. Lopez, "Integrating Wireless Sensor Networks and the Internet: A Security Analysis",
Internet Research, vol. 19, no. 2, Emerald, pp. 246-259, Mar 2009. DOI (I.F.: 0.844)More..

Abstract

Purpose: This paper aims to analyze the security issues that arise when integrating wireless sensor networks (WSN) and the internet. Also, it seeks to review whether existing technology mechanisms are suitable and can be applied in this context.

Design/methodology/approach: The paper considers the possible approaches that can be used to connect a WSN with the internet, and analyzes the security of their interactions.

Findings: By providing the services of the network through a front-end proxy, a sensor network and the internet can interact securely. There are other challenges to be solved if the sensor nodes are integrated into the internet infrastructure, although there exists interesting advances on his matter.

Research limitations and implications: The complete integration of sensor networks and the internet still remains as an open issue.

Practical implications: With the current state of the art, it is possible to develop a secure sensor network that can provide its services to internet hosts with certain security properties.

Originality/value: The paper studies the interactions between sensor networks and the internet from the point of view of security. It identifies both solutions and research challenges.

Impact Factor: 0.844
Journal Citation Reports® Science Edition (Thomson Reuters, 2009)

PDF icon roman2009a.pdf (394.32 KB)
R. Roman, J. Lopez, C. Alcaraz, and H. Hwa Chen, "SenseKey - Simplifying the Selection of Key Management Schemes for Sensor Networks",
5th International Symposium on Security and Multimodality in Pervasive Environments (SMPE’11), IEEE, March, 2011. DOI More..

Abstract

Key Management Schemes (KMS) are a very important security mechanism for Wireless Sensor Networks (WSN), as they are used to manage the credentials (i.e. secret keys) that are needed by the security primitives. There is a large number of available KMS protocols in the literature, but it is not clear what should network designers do to choose the most suitable protocol for the needs of their applications. In this paper, we consider that given a certain set of application requirements, the network designer can check which properties comply with those requirements and select the KMS protocols that contains those particular properties. Therefore, we study the relationship between requirements and properties, and we provide a web tool, the SenseKey tool, that can be used to automatically obtain an optimal set of KMS protocols.

PDF icon Roman11SK.pdf (143.01 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..

Abstract

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)
R. Roman, J. Zhou, and J. Lopez, "Casual Virtual Private Network",
International Journal of Computer Systems Science & Engineering, vol. 3, CRL Publishing, pp. 185-192, 2005. (I.F.: 0.119)More..

Abstract

Virtual Private Networks (VPNs) provide a cost-effective way for securing communications using public and insecure networks like the Internet. The main purpose of a VPN is to securely and transparently connect two or more remote networks to form virtually a single network, using centralized security policies for better management and protection. However, in certain scenarios, users may not require such a transparent access to the resources within their networks, but only want temporary secure access to internal services based on their own demands. We call the network architecture with such a feature as Casual VPN. In this paper, we present the notion of Casual VPN, and explain why traditional VPN architectures and protocols are unable to offer Casual VPN services. We also propose and define the operation of a particular Casual VPN architecture, C-VPN, which additionally allows the management of TCP and UDP-based protocols.

Impact Factor: 0.119
Journal Citation Reports® Science Edition (Thomson Reuters, 2005)

PDF icon Roman2005f.pdf (501.2 KB)
R. Roman, J. Lopez, and J. Zhou, "Aplicación de Sistemas de Detección de Intrusiones en Redes de Sensores",
Simposio sobre Computación Ubicua e Inteligencia Ambiental (UCAmI’05), pp. 113-120, September, 2005. More..

Abstract

Los sistemas de detección de intrusiones (IDS) son una herramienta imprescindible de seguridad a la hora de proteger una red. Recientemente se han investigado y desarrollado arquitecturas de IDS para redes inalámbricas, en concreto para redes "Ad Hoc". No obstante, no existe un trabajo previo que desarrolle una arquitectura de IDS para una red de sensores. En este artículo, analizamos porque los sistemas IDS de redes "Ad Hoc" no pueden aplicarse a redes de sensores, e introducimos una arquitectura de IDS para redes de sensores que incorpora una nueva técnica para vigilar las comunicaciones de la red en ciertos escenarios.

PDF icon Roman2005b.pdf (467.35 KB)
R. Roman, and J. Lopez, "KeyLED - Transmitting Sensitive Data over out-of-band Channels in Wireless Sensor Networks",
5th IEEE International Conference on Mobile Ad Hoc and Sensor Systems (MASS’08), IEEE, pp. 796-801, September, 2008. DOI More..

Abstract

An out-of-band (OoB) channel can be defined as an extra channel, different from the main wireless channel, that has additional security properties. They are specially suitable for protecting spontaneous interactions and exchanging sensitive data between previously unknown devices. Due to the vulnerable nature of wireless sensor networks (WSN), these kind of channels might be useful for protecting certain sensor network operations. In this paper we analyze the applicability of out-of-band channels to wireless sensor networks, and specify why an optical channel should be a good candidate for implementing an extra channel in sensor nodes. Also, we analyze how the existing security threats may affect this type of channel. Finally, the suitability and usability of optical channels for sensor networks is demonstrated by means of a prototype.

PDF icon Roman2008b.pdf (161.47 KB)
R. Roman, R. Rios, J. A. Onieva, and J. Lopez, "Immune System for the Internet of Things using Edge Technologies",
IEEE Internet of Things Journal, vol. 6, issue 3, IEEE Computer Society, pp. 4774-4781, 06/2019. DOI (I.F.: 9.936)More..

Abstract

The Internet of Things (IoT) and Edge Computing are starting to go hand in hand. By providing cloud services close to end-users, edge paradigms enhance the functionality of IoT deployments, and facilitate the creation of novel services such as augmented systems. Furthermore, the very nature of these paradigms also enables the creation of a proactive defense architecture, an immune system, which allows authorized immune cells (e.g., virtual machines) to traverse edge nodes and analyze the security and consistency of the underlying IoT infrastructure. In this article, we analyze the requirements for the development of an immune system for the IoT, and propose a security architecture that satisfies these requirements. We also describe how such a system can be instantiated in Edge Computing infrastructures using existing technologies. Finally, we explore the potential application of immune systems to other scenarios and purposes.

Impact Factor: 9.936
Journal Citation Reports® Science Edition (Thomson Reuters, 2019)

PDF icon roman2018VIS.pdf (149.3 KB)
R. Roman, and J. Lopez, "Especificación de Sistemas Electrónicos de Microdonaciones",
III Simposio Español de Comercio Electrónico, pp. 95-104, June, 2005. More..

Abstract

Los sistemas electrónicos de pago permiten que un comprador adquiera a un vendedor una serie de productos y servicios de forma virtual. Sin embargo, estos sistemas no tienen en cuenta el escenario en el que un comprador se convierte en donante, accediendo al servicio de forma gratuita. En este artículo se presenta el concepto y características de las microdonaciones, o la donación de cantidades tan pequeñas como un céntimo de euro en el contexto del comercio electrónico. También se muestra como la microdonación es algo necesario en el contexto actual de Internet, y como es posible su implementación basándose en sistemas de micropago.

PDF icon Roman2005c.pdf (362.76 KB)
R. Roman, C. Alcaraz, and N. Sklavos, "On the Hardware Implementation Efficiency of Cryptographic Primitives",
Wireless Sensor Network Security, J. Lopez, and J. Zhou Eds., IOS Press, 2008. More..

Abstract

Security has been proven a crucial factor in the provision of data services and especially in the computer-related environments. While wired and wireless networks come to all sectors of everyday life, security tries to satisfy the growing needs for confidentiality, integrity and non-repudiation. There are many instances of security primitives and each one of them has different requirements in terms of processing power, word size, etc. Therefore, it is important to review the functionality of the less resource-demanding encryption algorithms in order to analyze their theoretical suitability to the existent sensor node hardware. Still, the constraints inherent to the sensor nodes advise against the total dependence on software-based implementations, even more in the case of expensive primitives.

PDF icon Roman2008.pdf (394.11 KB)
R. Roman, J. Lopez, and J. Zhou, "Análisis de Seguridad en Redes Inalámbricas de Sensores",
V Jornadas de Ingenería Telemática (JITEL’05), pp. 335-343, Septiembre, 2005. More..

Abstract

The design and development of security infrastructures and protocols for Wireless Sensor Networks is a difficult task, due to several factors like the constraints of the sensor nodes and the public nature of the communication channels. The intrinsic features of these networks create numerous security problems. In this paper, we analyze and put into perspective those problems.

PDF icon R.Roman2005.pdf (233.58 KB)
R. Rios, D. Nuñez, and J. Lopez, "Query Privacy in Sensing-as-a-Service Platforms",
32nd International Conference on ICT Systems Security and Privacy Protection (IFIP SEC 2017), S. De Capitan di Vimercati, and F. Martinelli Eds., IFIP Advances in Information and Communication Technology (AICT) 502, Springer, pp. 141–154, 05/2017. DOI More..

Abstract

The Internet of Things (IoT) promises to revolutionize the way we interact with the physical world. Even though this paradigm is still far from being completely realized, there already exist Sensing-as-a-Service (S2aaS) platforms that allow users to query for IoT data. While this model offers tremendous benefits, it also entails increasingly challenging privacy issues. In this paper, we concentrate on the protection of user privacy when querying sensing devices through a semi-trusted S2aaS platform. In particular, we build on techniques inspired by proxy re-encryption and k-anonymity to tackle two intertwined problems, namely query privacy and query confidentiality. The feasibility of our solution is validated both analytically and empirically. 

PDF icon Rios2017query.pdf (367.05 KB)
R. Rios, J. Cuellar, and J. Lopez, "Ocultación de la estación base en redes inalámbricas de sensores",
XI Jornadas de Ingeniería Telemática (JITEL 2013), J. E. Díaz Verdejo, J. Navarro Ortiz, and J. J. Ramos Muñoz Eds., Asociación de Telemática, pp. 481-486, Oct 2013. More..

Abstract

La estación base es el elemento más importante en un red de sensores y, por tanto, es necesario evitar que un atacante pueda hacerse con el control de este valioso dispositivo. Para ello, el atacante puede valerse tanto de técnicas de análisis de tráfico como de la captura de nodos. En este trabajo presentamos un esquema que consta de dos fases, la primera está dedicada a homogeneizar los patrones de tráfico y la segunda encargada de perturbar las tablas de rutas de los nodos. Ambas fases permiten mantener a la estación base fuera del alcance del atacante con un coste computacional insignificante y un consumo energético moderado. La validez de nuestro esquema ha sido validada analíticamente y a través de numerosas simulaciones.

PDF icon rios2013b.pdf (348.08 KB)
R. Rios, and J. Lopez, "Evolución y nuevos desafios de privacidad en la Internet de las Cosas",
XIV Reunión Española sobre Criptología y Seguridad de la Información, pp. 209-213, 10/2016. More..

Abstract

La Internet de las Cosas (en inglés, Internet of Things (IoT)) es una evolución de la Internet tal y como lo conocemos. Esta nueva versión de Internet incorpora objetos de la vida cotidiana, rompiendo así barrera de los digital y extendiéndose al mundo físico. Estos objetos interactuarán entre sí y con otras entidades tanto de manera local como remota, y estarán dotados de cierta capacidad computacional y sensores para que sean conscientes de lo que ocurre en su entorno. Esto traerá consigo un sinfín de posibilidades y nuevos servicios, pero también dará lugar a nuevos y mayores riesgos de privacidad para los ciudadanos. En este artículo, estudiamos los problemas de privacidad actuales de una de las tecnologías claves para el desarrollo de este prometedor paradigma, las redes de sensores, y analizamos como pueden evolucionar y surgir nuevos riesgos de privacidad al ser completamente integradas en la Internet.

 

PDF icon Rios2016a.pdf (263.7 KB)
R. Rios, and J. Lopez, "Adecuación de soluciones de anonimato al problema de la privacidad de localización en WSN",
XII Reunión Española sobre Criptología y Seguridad de la Información (RECSI 2012), U.. Zurutuza, R.. Uribeetxeberria, and I.. Arenaza-Nuño Eds., pp. 309-314, Sep 2012. More..

Abstract

Los patrones de tráfico característicos de las redes inalámbricas de sensores (WSNs) dan lugar al problema de la privacidad de localización. De manera similar, el tráfico de los usuarios en Internet revela información sensible que puede ser protegida mediante sistemas de comunicación anónima (ACS). Por ello, este trabajo analiza la posibilidad de adaptar las soluciones de anonimato tradicionales al problema particular de las redes de sensores. Hasta el momento estas soluciones habían sido rechazadas sin un análisis riguroso, argumentando simplemente que eran demasiado exigentes computacionalmente para los nodos sensores. Nuestros resultados demuestran que, en general, algunos ACS no cumplen los requisitos de privacidad necesarios en WSNs mientras que otros, que si los cumplen, se valen de una cantidad de recursos que superan la capacidad de los sensores.

PDF icon Rios2012b.pdf (156.9 KB)
R. Rios, and J. Lopez, "Exploiting Context-Awareness to Enhance Source-Location Privacy in Wireless Sensor Networks",
The Computer Journal, vol. 54, Oxford University Press, pp. 1603-1615, Sept 2011. DOI (I.F.: 0.785)More..

Abstract

The source-location privacy problem in Wireless Sensor Networks has been traditionally tackled by the creation of random routes for every packet transmitted from the source nodes to the base station. These schemes provide a considerable protection level at a high cost in terms of message delivery time and energy consumption. This overhead is due to the fact that the data routing process is done in a blind way, without knowledge about the location of the attacker. In this work we propose the Context-Aware Location Privacy (CALP) approach, which takes advantage of the ability of sensor nodes to perceive the presence of a mobile adversary in their vicinity in order to transmit data packets in a more energy-efficient and privacy-preserving manner. In particular, we apply the concepts of CALP to the development of a shortest-path CALP routing algorithm. A permissive and a strict version of the protocol are studied for different adversarial models and the proposed schemes are evaluated through simulation experiments in terms of privacy protection and energy consumption. Finally, we present the conclusions of the paper as well as possible extensions of this work.

Impact Factor: 0.785
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon Rios2011b.pdf (573.86 KB)
R. Rios, J. Cuellar, and J. Lopez, "Probabilistic receiver-location privacy protection in wireless sensor networks",
Information Sciences, vol. 321, Elsevier, pp. 205 - 223, 07/2015. DOI (I.F.: 3.364)More..

Abstract

Wireless sensor networks (WSNs) are continually exposed to many types of attacks. Among these, the attacks targeted at the base station are the most devastating ones since this essential device processes and analyses all traffic generated in the network. Moreover, this feature can be exploited by a passive adversary to determine its location based on traffic analysis. This receiver-location privacy problem can be reduced by altering the traffic pattern of the network but the adversary may still be able to reach the base station if he gains access to the routing tables of a number of sensor nodes. In this paper we present HISP-NC (Homogenous Injection for Sink Privacy with Node Compromise protection), a receiver-location privacy solution that consists of two complementary schemes which protect the location of the base station in the presence of traffic analysis and node compromise attacks. The HISP-NC data transmission protocol prevents traffic analysis by probabilistically hiding the flow of real traffic with moderate amounts of fake traffic. Moreover, HISP-NC includes a perturbation mechanism that modifies the routing tables of the nodes to introduce some level of uncertainty in attackers capable of retrieving the routing information from the nodes. Our scheme is validated both analytically and experimentally through extensive simulations.

Impact Factor: 3.364
Journal Citation Reports® Science Edition (Thomson Reuters, 2015)

PDF icon rios2015.pdf (692.33 KB)
R. Rios, C. Fernandez-Gago, and J. Lopez, "Privacy-Aware Trust Negotiation",
12th International Workshop on Security and Trust Management (STM), vol. LNCS 9871, Springer, pp. 98-105, 09/2016. DOI More..

Abstract

Software engineering and information security have traditionally followed divergent paths but lately some efforts have been made to consider security from the early phases of the Software Development Life Cycle (SDLC). This paper follows this line and concentrates on the incorporation of trust negotiations during the requirements engineering phase. More precisely, we provide an extension to the SI* modelling language, which is further formalised using answer set programming specifications to support the automatic verification of the model and the detection of privacy conflicts caused by trust negotiations.

PDF icon rios2016b.pdf (237.78 KB)
R. Rios, J. Lopez, and J. Cuellar, "Location Privacy in WSNs: Solutions, Challenges, and Future Trends",
Foundations of Security Analysis and Design VII, vol. 8604, no. LNCS, Springer, pp. 244-282, 2014. DOI More..

Abstract

Privacy preservation is gaining popularity in Wireless Sensor Network (WSNs) due to its adoption in everyday scenarios. There are a number of research papers in this area many of which concentrate on the location privacy problem. In this paper we review and categorise these solutions based on the information available to the adversary and his capabilities. But first we analyse whether traditional anonymous communication systems conform to the original requirements of location privacy in sensor networks. Finally, we present and discuss a number of challenges and future trends that demand further attention from the research community.

PDF icon ruben2014a.pdf (686.66 KB)
R. Rios, and J. Lopez, "(Un)Suitability of Anonymous Communication Systems to WSN",
IEEE Systems Journal, vol. 7, no. 2, IEEE Systems Council, pp. 298 - 310, Jun 2013. DOI (I.F.: 1.746)More..

Abstract

Anonymous communication systems have been extensively studied by the research community to prevent the disclosure of sensitive information from the analysis of individuals’ traffic patterns. Many remarkable solutions have been developed in this area, most of which have proven to be effective in the protection of user privacy against different types of attacks. Recently, the privacy preservation problem has also been considered in the realm of wireless sensor networks (WSNs) due to their imminent adoption in real-world scenarios. A special challenge that arises from the analysis of the flow of sensor nodes’ communications is the location privacy problem. In this work we concentrate on analyzing the suitability of traditional anonymous communication systems originally designed for the Internet to the original scenario of sensor networks. The results show that, in most cases, traditional solutions do not provide the adequate protection means for the particular problem of location privacy, while other solutions are too resource-consuming for the restricted capabilities of sensor nodes.

Impact Factor: 1.746
Journal Citation Reports® Science Edition (Thomson Reuters, 2013)

PDF icon Rios2012a.pdf (488.58 KB)
R. Rios, and J. A. Onieva, "Clasificación de canales encubiertos. Un nuevo canal: Covert_DHCP",
X Reunión Española de Criptología y Seguridad de la Información (RECSI’08), L. Hernández Encinas, and A. Martin del Rey Eds., pp. 325-336, Sept., 2008. More..

Abstract

Los canales encubiertos son una forma de comunicación oculta que puede vulnerar la integridad de los sistemas. Desde sus inicios en sistemas de seguridad multinivel a principios de los años 70 han evolucionado considerablemente, apareciendo soluciones para redes de computadores debido a la especificación de algunos protocolos. Por este motivo, se hace un estudio sobre las técnicas que se han utilizado para crear los canales, así como sobre las distintos obstáculos que han tratado de mermar su actividad. Asimismo, se presenta una nueva clasificación que trata de albergar la mayor cantidad de canales encubiertos existentes en la actualidad. Por último, se analiza un protocolo ampliamente extendido en la actualidad, DHCP, en busca de posibilidades de albergar información encubierta. A partir de este análisis se implementan distintas versiones de un canal encubierto haciendo uso de este protocolo.

PDF icon Rios2008.pdf (397.05 KB)
R. Rios, and J. Lopez, "Source Location Privacy Considerations in Wireless Sensor Networks",
4th International Symposium of Ubiquitous Computing and Ambient Intelligence (UCAmI’10), L. Fuentes, N. Gámez, and J. Bravo Eds., IBERGARCETA PUBLICACIONES, S.L., pp. 29 - 38, Sept., 2010. More..

Abstract

Wireless Sensor Networks are considered to be one of the cornerstones of Ambient Intelligence since they can be used in countless applications, where sensors are unobtrusively embedded into the environment to perform operations like monitoring, tracking and reporting. In such scenarios, privacy issues must be carefully considered since the mere observation of the network operation might reveal great amounts of private information to unauthorised parties. One of the problems that is gaining more attention in the realm of privacy, is the location privacy problem, which aims to prevent an attacker from obtaining the location of specific nodes of interest to him. In this paper we provide a general overview of the proposed solutions to counter this threat. Finally, we will also discuss some open challenges and future directions of research for a convenient management of privacy issues in smart environments.

PDF icon Rios2010.pdf (352.58 KB)
R. Rios, C. Fernandez-Gago, and J. Lopez, "Modelling Privacy-Aware Trust Negotiations",
Computers & Security, vol. 77 , issue August 2018, Elsevier, pp. 773-789, 2018. DOI (I.F.: 3.062)More..

Abstract

Trust negotiations are mechanisms that enable interaction between previously unknown users. After exchanging various pieces of potentially sensitive information, the participants of a negotiation can decide whether or not to trust one another. Therefore, trust negotiations bring about threats to personal privacy if not carefully considered. This paper presents a framework for representing trust negotiations in the early phases of the Software Development Life Cycle (SDLC). The framework can help software engineers to determine the most suitable policies for the system by detecting conflicts between privacy and trust requirements. More precisely, we extend the SI* modelling language and provide a set of predicates for defining trust and privacy policies and a set of rules for describing the dynamics of the system based on the established policies. The formal representation of the model facilitates its automatic verification. The framework has been validated in a distributed social network scenario for connecting drivers with potential passengers willing to share a journey.

Impact Factor: 3.062
Journal Citation Reports® Science Edition (Thomson Reuters, 2018)

PDF icon Ruben2017trust.pdf (425.82 KB)
R. Rios, J. A. Onieva, and J. Lopez, "HIDE_DHCP: Covert Communications Through Network Configuration Messages",
Proceedings of the 27th IFIP TC 11 International Information Security and Privacy Conference (SEC 2012), D. Gritzalis, S. Furnell, and M. Theoharidou Eds., IFIP AICT 376, Springer Boston, pp. 162-173, June 2012. DOI More..

Abstract

Covert channels are a form of hidden communication that may violate the integrity of systems. Since their birth in multilevel security systems in the early 70’s they have evolved considerably, such that new solutions have appeared for computer networks mainly due to vague protocols specifications. We analyze a protocol extensively used today, the Dynamic Host Configuration Protocol (DHCP), in search of new forms of covert communication. From this analysis we observe several features that can be effectively exploited for subliminal data transmission. This results in the implementation of HIDE_DHCP, which integrates three covert channels that accommodate to different stealthiness and bandwidth requirements

PDF icon Rios2012.pdf (400 KB)
R. Rios, R. Roman, J. A. Onieva, and J. Lopez, "From Smog to Fog: A Security Perspective",
2nd IEEE International Conference on Fog and Edge Mobile Computing (FMEC 2017), IEEE Computer Society, pp. 56-61, 06/2017. DOI More..

Abstract

Cloud computing has some major limitations that hinder its application to some specific scenarios (e.g., Industrial IoT, and remote surgery) where there are particularly stringent requirements, such as extremely low latency. Fog computing is a specialization of the Cloud that promises to overcome the aforementioned limitations by bringing the Cloud closer to end-users. Despite its potential benefits, Fog Computing is still a developing paradigm which demands further research, especially on security and privacy aspects. This is precisely the focus of this paper: to make evident the urgent need for security mechanisms in Fog computing, as well as to present a research strategy with the necessary steps and processes that are being undertaken within the scope of the SMOG project, in order to enable a trustworthy and resilient Fog ecosystem.

PDF icon Ruben2017smog.pdf (486.34 KB)
R. Rios, J. A. Onieva, and J. Lopez, "Covert Communications through Network Configuration Messages",
Computers & Security, vol. 39, Part A, Elsevier, pp. 34 - 46, Nov 2013. DOI (I.F.: 1.172)More..

Abstract

Covert channels are a form of hidden communication that may violate the integrity of systems. Since their birth in Multi-Level Security systems in the early 70’s they have evolved considerably, such that new solutions have appeared for computer networks mainly due to vague protocols specifications. In this paper we concentrate on short-range covert channels and analyze the opportunities of concealing data in various extensively used protocols today. From this analysis we observe several features that can be effectively exploited for subliminal data transmission in the Dynamic Host Configuration Protocol (DHCP). The result is a proof-of-concept implementation, HIDE\_DHCP, which integrates three different covert channels each of which accommodate to different stealthiness and capacity requirements. Finally, we provide a theoretical and experimental analysis of this tool in terms of its reliability, capacity, and detectability.

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

PDF icon rios2013a.pdf (565.05 KB)
R. Rios, and J. Lopez, "Analysis of Location Privacy Solutions in Wireless Sensor Networks",
IET Communications, vol. 5, Institution of Engineering and Technology, pp. 2518 - 2532, Nov 2011. DOI (I.F.: 0.829)More..

Abstract

Extensive work has been done on the protection of Wireless Sensor Networks (WSNs) from the hardware to the application layer. However, only recently, the privacy preservation problem has drawn the attention of the research community because of its challenging nature. This problem is exacerbated in the domain of WSNs due to the extreme resource limitation of sensor nodes. In this paper we focus on the location privacy problem in WSNs, which allows an adversary to determine the location of nodes of interest to him. We provide a taxonomy of solutions based on the power of the adversary and the main techniques proposed by the various solutions. In addition, we describe and analyse the advantages and disadvantages of different approaches. Finally, we discuss some open challenges and future directions of research.

Impact Factor: 0.829
Journal Citation Reports® Science Edition (Thomson Reuters, 2011)

PDF icon Rios2011a.pdf (597.01 KB)
R. Rios, I. Agudo, and J. L. Gonzalez, "Implementación de un esquema de localización privada y segura para interiores",
IX Jornadas de Ingeniería Telemática (JITEL’10), Y. Dimitriadis, and M. Jesús Ver Pérez Eds., pp. 237 - 244, Sept., 2010. More..

Abstract

Las aplicaciones basadas en localización proporcionan a los usuarios servicios personalizados dependiendo de su ubicación. Las estimaciones prevén que estos servicios se extenderán enormemente en los próximos años reportando grandes beneficios tanto a la industria como a los usuarios finales. Sin embargo, para que estos avances sean posibles se hace necesario analizar en profundidad las distintas implicaciones de seguridad y privacidad que la utilización de tales servicios pueden traer consigo a los usuarios. En este trabajo proponemos un sistema de localización que da soporte a la provisión de servicios basados en localización para entornos indoor y que se fundamenta en la tecnología de redes de sensores inalámbricos. En este esquema hemos tenido en cuenta diversos aspectos de seguridad y privacidad, prestando especial atención a la limitación extrema de recursos característica de las redes de sensores. Finalmente hemos desarrollado una prueba de concepto para comprobar la viabilidad de nuestro esquema dentro del ámbito del proyecto OSAmI.

PDF icon Rios2010a.pdf (311.53 KB)
R. Rios, J. Lopez, and J. Cuellar, "Location Privacy in Wireless Sensor Networks",
CRC Series in Security, Privacy and Trust, Taylor & Francis, 2016. More..
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..

Abstract

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)
G. Ramos, J. Lopez, and R. Morales, "Comparisons of Parikh’s conditions to other conditions for context-free languages",
Theoretical Computer Science, vol. 202, no. 1-2, Elsevier, pp. 231-244, 1998. (I.F.: 0.349)More..

Abstract

  this paper we first compare Parikh’s condition to various pumping conditions - Bar- Hillel’s pumping lemma, Ogden’s condition and Bader-Moura’s condition; secondly, to interchange condition; and finally, to Sokolowski’s and Grant“s conditions. In order to carry out these comparisons we present some properties of Parikh’s languages. The main result is the orthogonality of the previously mentioned conditions and Parikh’s condition. In

Impact Factor: 0.349
Journal Citation Reports® Science Edition (Thomson Reuters, 1998)

PDF icon GonzaloRamos1998.pdf (792.29 KB)
G. Ramos, and J. Lopez, "ID3f+A. Algoritmo de Aprendizaje Inductivo Borroso con División Intervalar Automática de los Atributos",
VI Congreso Español Sobre Tecnologías y Lógica Fuzzy (ESTYLF’96), pp. 225-230, Septiembre, 1996. More..

Abstract

Uno de los campos más prometedores dentro del estudio de la ambigüedad es el del aprendizaje, tanto por su importancia consusntacial como por su relación con la Inteligencia Artificial. Esta relación se hace evidente cuando intentamos resolver, desde una perspectiva borrosa, el problema de la adquisición automática del conocimiento en sistemas expertos. El algoritmo ID3, el más relevante de los utilizados para la inducción de árboles de decisión, no es utilizable tal cual con un concepto borroso del concepto de pertenencia. Además se muestra ineficiente cuando no existe un experto humano que defina correctamente los subrangos de actuación para los atributos que junto a las clases expresan las relaciones entre situaciones que este algoritmo de aprendizaje intenta descubrir. Proponemos como solución un nuevo algoritmo, el ID3f+A, que posee la capacidad de tratamiento borroso del concepto de pertenencia, gracias a una modificación del concepto de entropía, y además realiza la división intervalar automática de los atributos, merced al control del proceso inductivo por medio de la utilización de experiencias de control.

PDF icon GonzaloRamos1996.pdf (425.41 KB)