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A
C. Fernandez-Gago, et al., "A4Cloud Workshop: Accountability in the Cloud",
IFIP Sumer School 2015 on Privacy and Identity Management. Time for a Revolution?, vol. 476, AICT Series, Springer, pp. 61-78, 07/2016.
C. Fernandez-Gago, et al., "A4Cloud Workshop: Accountability in the Cloud",
IFIP Sumer School 2015 on Privacy and Identity Management. Time for a Revolution?, vol. 476, AICT Series, Springer, pp. 61-78, 07/2016.
C. Fernandez-Gago, M. Fisher, and C. Dixon, "An Algorithm for Guiding Clausal Temporal Resolution",
4th International Workshop on Strategies in Automated Deduction (STRATEGIES’01), June, 2001. More..

Abstract

The clausal resolution method developed for discrete temporal log- ics involves translation to a normal form, classical resolution on formulae within states (termed step resolution) and temporal resolution between states. Step res- olution may generate an unnecessarily large set of clauses. In addition, the most expensive part of the method is the application of the temporal resolution oper- ation. In this paper we develop an algorithm to guide the search for the set of clauses needed for the application of temporal resolution. The algorithm is based on the outputs of a refined temporal resolution rule which allows us to generate temporal resolvents earlier within the process. In particular, this can also help us to avoid unnecessary step resolution and focus search for the most relevant clauses.

PDF icon Fernandez01.pdf (847.21 KB)
C. Fernandez-Gago, M. Fisher, and C. Dixon, "Algorithms for Guiding Clausal Temporal Resolution",
25th Conference on Artificial Intelligence (KI’02), LNAI 2479, Springer, pp. 235-249, September, 2002. More..

Abstract

Clausal temporal resolution is characterised by a translation of the formulae whose satisfiability is to be established to a normal form, step resolution (similar to classical resolution) on formulae occurring at the same states and temporal resolution between formulae describing properties over a longer period. The most complex part of the method occurs in searching for candidates for the temporal resolution operation, something that may need to be carried out several times. In this paper we consider a new technique for finding the candidates for the temporal resolution operation. Although related to the previously developed external search procedure, this new approach not only allows the temporal resolution operation to be carried out at any moment, but also simplifies any subsequent search required for similar temporal formulae. Finally, in contrast with previous approaches, this search can be seen as an inherent part of the resolution process, rather than an external procedure that is only called in certain situations.} year = {2002

PDF icon Fernandez02.pdf (228.08 KB)
J.. Zhou, K. T. Das, and J. Lopez, "An Asynchronous Node Replication Attack in Wireless Sensor Networks",
23rd International Information Security Conference (SEC 2008), vol. 278, pp. 125-139, 2008.
B
E. Dawson, J. Lopez, J. A. Montenegro, and E. Okamoto, "BAAI: Biometric Authentication and Authorization Infrastructure",
IEEE International Conference on Information Technology (ITRE’03), IEEE, pp. 274-278, 2003. DOI More..

Abstract

The combined use of authorization and authentication infrastructures has led to AAIs (authorization and authentication infrastructures). These new infrastructures supply identification and authorization services to a distributed environment There are many possibilities of linkages to get AAIs; one of them is to include the PMI (privilege management infrastructure) as authorization infrastructure and an authentication infrastructure that can be a PKI (public key infrastructure) or kerberos. This symbiosis gives service to applications and servers. However, in physical environments where the physical presence of an individual is required, it is necessary to use biometric systems. This paper describes the development of a solution that combines the relationship between the biometric based systems and the PMIs to finally obtain the biometric AAI.

C
E. Okamoto, et al., "Certificate Retrieval and Validation in Online Systems",
Symposium on Cryptography and Information Security (SCIS’03), pp. 25-30, January, 2003. More..

Abstract

In order to more effectively deal with certificate management issues in PKIs, there is growing interest in supplementing offline X.509 PKI models with online services. An analysis of the security requirements of online models will be presented. Proposed online and delegated processing models will be evaluated in relation to these requirements.

PDF icon EijiOkamoto2003.pdf (146.11 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)
J. A. Onieva, I. Agudo, J. Lopez, G.. Drapper-Gil, and M.F.. Hinarejos, "Como proteger la privacidad de los usuarios en Internet. Verificación anónima de la mayoría de edad",
XII Reunión Española sobre Criptología y Seguridad de la Información - RECSI 2012, Mondragon, pp. 297-302, Sep 2012. More..
PDF icon onieva2012.pdf (676.25 KB)
D
I. Agudo, J. Lopez, J. A. Montenegro, E. Okamoto, and E. Dawson, "Delegation Perspective of Practical Authorization Schemes",
Fifth International Network Conference (INC’05), pp. 157-164, 2005. More..
PDF icon IsaacAgudo2005a.pdf (64.72 KB)
J. Lopez, J. A. Montenegro, R. Roman, and J. Davila, "Design of a VPN Software Solution Integrating TCP and UDP Services",
International Conference on Infrastructure Security (InfraSec’02), LNCS 2437, Springer-Verlag, pp. 325-337, October, 2002. More..

Abstract

The main aims of Virtual Private Network (VPN) are to isolate a distributed network from outsiders, as well as to protect the confidentiality and integrity of sensitive information traversing a non-trusted network such as the Internet. However, some problems arise when security is considered as the unique problem because VPN users suffer from restrictions in their access to the network. They are not free to use traditional Internet services such as electronic mail exchange with non-VPN users, and to access Web and FTP servers external to the organization. This paper presents a new solution that allows the open use of traditional network services running over TCP and UDP layers, while maintaining strong security features. The new scheme works at the TCP/IP transport layer and does not require the addition of new hardware because it is a totally software solution. As a consequence, the application is totally portable. Moreover, and because of its implementation at the transport layer, there is no need to modify any traditional communication applications previously installed in the network system.

PDF icon JavierLopez2002c.pdf (126.07 KB)
J. Davila, J. Lopez, A. Mana, J. J. Ortega, and J. maria troya, "Development of Secure Internet Applications for Governmental Environments",
IEEE International Workshop on Electronic Government (in DEXA’00), IEEE Press, pp. 362-365, 2000.
F
J. Davila, J. Lopez, R. Peralta, and J. maria troya, "A First Approach to Latin Electronic Notary Public Services",
IFIP Conference on Security & Control of IT in Security, pp. 49-60, 2001.
I
D. Nuñez, I. Agudo, P. Drogkaris, and S. Gritzalis, "Identity Management Challenges for Intercloud Applications",
1st International Workshop on Security and Trust for Applications in Virtualised Environments (STAVE 2011), vol. 187, pp. 198-204, June, 2011. DOI More..

Abstract

Intercloud notion is gaining a lot of attention lately from both enterprise and academia, not only because of its benefits and expected results but also due to the challenges that it introduces regarding interoperability and standardisation. Identity management services are one of the main candidates to be outsourced into the Intercloud, since they are one of the most common services needed by companies and organisations. This paper addresses emerging identity management challenges that arise in intercloud formations, such as naming, identification, interoperability, identity life cycle management and single sign-on.

PDF icon DNunez11.pdf (162.14 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)
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)
J. Davila, L. Fuentes, J. Lopez, J. maria troya, and A. Vallecillo, "Internet Secure Communications Between Citizens and Public Administrations",
IFIP Conference on Advances in Electronic Government, pp. 109-120, 2000.
J. Davila, J. Lopez, and R. Roman, "Introducción de Aplicaciones UDP en Redes Privadas Virtuales",
III Jornadas de Ingeniería Telemática (JITEL’01), pp. 397-404, Septiembre, 2001. More..

Abstract

Virtual Private Network (VPN) solutions mainly focus on security aspects. However, when security is considered the unique problem, some collateral ones arise. VPN users suffer from restrictions in their access to the network. They are not free to use traditional Internet services such as electronic mail exchange and audio/video conference with non-VPN users, and to access Web and Ftp servers external to the organization. In this paper we present a new solution, located at the TCP/IP transport layer and oriented to UDP applications that, while maintaining strong security features, allows the open use of traditional network services. The solution does not require the addition of new hardware because it is an exclusively software solution. As a consequence, the application is totally portable.

PDF icon JorgeDavila2001.pdf (44.79 KB)
N
E. Dawson, J. Lopez, J. A. Montenegro, and E. Okamoto, "A New Design of Privilege Management Infrastructure (PMIs) for Organizations Using Outsourced PKI",
5th International Conference on Information Security (ISC’02), LNCS 2433, Springer-Verlag, pp. 136-149, September, 2002. DOI More..

Abstract

Authentication services provided by Public Key Infrastructures (PKI) do not satisfy the needs of many e-commerce applications. These applications require additional use of authorization services in order for users to prove what they are allowed to do. Attribute certificates have changed the way in which the authorization problem has been considered until now, and Privilege Management Infrastructures (PMI) provide the necessary support for a wide use of those certificates. Although both types of infrastructures, PKIs and PMIs, keep some kind of relation, they can operate autonomously. This fact is specially interesting for companies who have taken or will take the decision to outsource PKI services. However, outsourcing PMI services is not a good option for many companies because sometimes information contained in attribute certificates is confidential. Therefore attribute certificates must be managed very carefully and, preferably, only inside the company. In this paper we present a new design of PMI that is specially suited for those companies that outsource PKI services but still need to manage the PMI internally. The scheme provides additional advantages that satisfy the needs of intra-company attribute certification, and eliminates some of the problems associated with the revocation procedures.

K.. Peng, E. Dawson, J. Gonzalez-Nieto, E. Okamoto, and J.. Lopez, "A Novel Method To Maintain Privacy in Mobile Agent Applications",
Fourth International Conference on Cryptology and Network Security (CANS´05), LNCS 3810, Springer, pp. 247-260, 2005. More..
PDF icon 1716.pdf (211.06 KB)
O
W.. Caelli, et al., "Online Public Key Infrastructure",
VII Reunión Española sobre Criptología y Seguridad de la Información (VII RECSI), pp. 123-135, Sep 2002.
N. Dai, et al., "OSAMI Commons: An open dynamic services platform for ambient intelligence",
IEEE 16th Conference on Emerging Technologies Factory Automation (ETFA 2011), IEEE, pp. 1-10, Sep 2011. DOI More..

Abstract

Today we live in an environment surrounded with networked converging devices. Human computer interactions are becoming personalized and a new concept of a global and cross-domain platform is emerging to exploit the full potential of the network in all business areas. In this convergence process, the software platform should be able to personalize itself dynamically in devices according to the context. OSAmI-Commons, an ITEA2 project for developing an open-source common approach to such a dynamic service-based platform, allows any type of device to connect and exchange information and services. OSAMI consortium is contributing to defining the foundations of a cross-platform open-services ecosystem. The sustainability of this platform is an objective beyond the project duration.

N. Dai, et al., "OSAMI Commons: An open dynamic services platform for ambient intelligence",
IEEE 16th Conference on Emerging Technologies Factory Automation (ETFA 2011), IEEE, pp. 1-10, Sep 2011. DOI More..

Abstract

Today we live in an environment surrounded with networked converging devices. Human computer interactions are becoming personalized and a new concept of a global and cross-domain platform is emerging to exploit the full potential of the network in all business areas. In this convergence process, the software platform should be able to personalize itself dynamically in devices according to the context. OSAmI-Commons, an ITEA2 project for developing an open-source common approach to such a dynamic service-based platform, allows any type of device to connect and exchange information and services. OSAMI consortium is contributing to defining the foundations of a cross-platform open-services ecosystem. The sustainability of this platform is an objective beyond the project duration.

Q
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)
S
D. Ferraris, C. Fernandez-Gago, J. Daniel, and J. Lopez, "A Segregated Architecture for a Trust-based Network of Internet of Things",
IEEE Consumer Communications & Networking Conference 2019, IEEE, 03/2019. DOI More..

Abstract

With the ever-increasing number of smart home devices, the issues related to these environments are also growing. With an ever-growing attack surface, there is no standard way to protect homes and their inhabitants from new threats. The inhabitants are rarely aware of the increased security threats that they are exposed to and how to manage them. To tackle this problem, we propose a solution based on segmented architectures similar to the ones used in industrial systems. In this approach, the smart home is segmented into various levels, which can broadly be categorised into an inner level and external level. The external level is protected by a firewall that checks the communication from/to the Internet to/from the external devices. The internal level is protected by an additional firewall that filters the information and the communications between the external and the internal devices. This segmentation guarantees a trusted environment between the entities belonging to the internal network. In this paper, we propose an adaptive trust model that checks the behaviour of the entities and, through this model, in case the entities violate trust rules they can be put in quarantine or banned from the network.

PDF icon 1780.pdf (227.72 KB)
U
G. Draper-Gil, J. L. Ferrer-Gomilla, M.F.. Hinarejos, J. A. Onieva, and J. Lopez, "Un protocolo para la firma de contratos en escenarios multi-two-party con atomicidad",
XII Reunión Española de Criptología y Seguridad de la Información, pp. 357-362, 09/2012. More..

Abstract

Los avances tecnológicos que está experimentando el mundo digital (Internet, comunicaciones, etc.) están acercando a consumidores y proveedores. Los proveedores pueden ofrecer sus productos directamente a los consumidores finales, y éstos son capaces de acceder a los proveedores desde cualquier lugar y en cualquier momento. A la hora de adquirir productos o
servicios, esta facilidad de acceso permite a los consumidores consultar distintas ofertas de diferentes proveedores. Pero en el caso de que el consumidor quiera múltiples productos, como los paquetes turísticos, formados por vuelos, hoteles, excursiones, etc, los consumidores carecen de herramientas que les permitan realizar la contratación multi-two-party de manera atómica. En
este artículo presentamos un protocolo de firma de contratos multi-two-party con atomicidad que garantiza la equitatividad de todas las partes.

PDF icon 422.pdf (93.98 KB)
J.. Davila, J. Lopez, and R.. Peralta, "Una Solución Flexible para Redes Privadas Virtuales",
VI Reunión Española de Criptología y Seguridad de la Información (VI RECSI), pp. 329-340, Sep 2000.
C. Dixon, C. Fernandez-Gago, M. Fisher, and W. van der Hoek, "Using Temporal Logics of Knowledge in the Formal Verification of Security Protocols",
11th International Symposium on Temporal Representation and Reasoning (TIME’04), IEEE Computer Society, pp. 148-151, 2004. DOI More..

Abstract

Temporal logics of knowledge are useful for reasoning about situations where the knowledge of an agent or component is important, and where change in this knowledge may occur over time. Here we use temporal logics of knowledge to reason about security protocols. We show how to specify part of the Needham-Schroeder protocol using temporal logics of knowledge and prove various properties using a clausal resolution calculus for this logic.

PDF icon Dix04.pdf (54.5 KB)