25th European Symposium on Research in Computer Security (ESORICS 2020), vol. 12308, pp. 174-192, 09/2020. DOI
XV Reunión Española sobre Criptología y Seguridad de la Información, 10/2018.
Con la revolución tecnológica que ha supuesto la Internet de las Cosas (Internet of Things, IoT) se han presentado escenarios donde la preocupación por la seguridad en dicho entorno es cada vez más relevante. Están comenzando a surgir vulnerabilidades en varios dispositivos, y los sistemas trampa son una excelente manera de lidiar con este problema. En este trabajo se analizan soluciones para honeypots en el entorno IoT (y en otros que se puedan adaptar) para sentar las bases de una metodología que permita el despliegue de honeypots IoT.
16th IEEE International Conference On Trust, Security And Privacy In Computing And Communications (TrustCom 2017), IEEE, pp. 642-649, 08/2017. DOI
The digital witness approach defines the collaboration between IoT devices - from wearables to vehicles - to provide digital evidence through a Digital Chain of Custody to an authorised entity. As one of the cores of the digital witness, binding credentials unequivocally identify the user behind the digital witness. The objective of this article is to perform a critical analysis of the digital witness approach from the perspective of privacy, and to propose solutions that help include some notions of privacy in the scheme (for those cases where it is possible). In addition, digital anonymous witnessing as a tradeoff mechanism between the original approach and privacy requirements is proposed. This is a clear challenge in this context given the restriction that the identities of the links in the digital chain of custody should be known.
Proceedings of the 13th International Joint Conference on e-Business and Telecommunications (SECRYPT 2016), pp. 19-27, 2016. DOI
Increasingly, automatic restoration is an indispensable security measure in control systems (e.g. those used in critical infrastructure sectors) due to the importance of ensuring the functionality of monitoring infrastructures. Modernizing the interconnection of control systems to provide interoperability between different networks, at a low cost, is also a critical requirement in control systems. However, automated recovery mechanisms are currently costly, and ensuring interoperability particularly at a low cost remains a topic of scientific challenge. This is the gap we seek to address in this paper. More specifically, we propose a restoration model for interconnected contexts, taking into account the theory of supernode and structural controllability, as well as the recommendations given by the IEC-62351-8 standard (which are mainly based on the implementation of a role-based access control system).
IEEE International Conference on Cloud Computing Technology and Science (CloudCom 2014), IEEE, pp. 374-379, 12/2014. DOI
Among Big Data technologies, Hadoop stands out for its capacity to store and process large-scale datasets. However, although Hadoop was not designed with security in mind, it is widely used by plenty of organizations, some of which have strong data protection requirements. Traditional access control solutions are not enough, and cryptographic solutions must be put in place to protect sensitive information. In this paper, we describe a cryptographically-enforced access control system for Hadoop, based on proxy re-encryption. Our proposed solution fits in well with the outsourcing of Big Data processing to the cloud, since information can be stored in encrypted form in external servers in the cloud and processed only if access has been delegated. Experimental results show that the overhead produced by our solution is manageable, which makes it suitable for some applications.
8th International Conference on Availability, Reliability and Security, IEEE, pp. 121-130, Nov 2013. DOI
The number of insider threats hitting organizations and big enterprises is rapidly growing. Insider threats occur when trusted employees misuse their permissions on organizational assets. Since insider threats know the organization and its processes, very often they end up undetected. Therefore, there is a pressing need for organizations to adopt preventive mechanisms to defend against insider threats. In this paper, we propose a framework for insiders identification during the early requirement analysis of organizational settings and of its IT systems. The framework supports security engineers in the detection of insider threats and in the prioritization of them based on the risk they represent to the organization. To enable the automatic detection of insider threats, we extend the SI* requirement modeling language with an asset model and a trust model. The asset model allows associating security properties and sensitivity levels to assets. The trust model allows specifying the trust level that a user places in another user with respect to a given permission on an asset. The insider threats identification leverages the trust levels associated with the permissions assigned to users, as well as the sensitivity of the assets to which access is granted. We illustrate the approach based on a patient monitoring scenario.
XI Reunión Española sobre Criptología y Seguridad de la Información (RECSI 2010), September, 2010.
En la actualidad, cada vez son más frecuentes los ataques software mediante la utilización de malware o sustitución de programas (o componentes) en los repositorios a los cuales los usuarios finales (o máquinas) acceden. Esta situación se ve de alguna manera acentuada con el dinamismo existente en la programación y ejecución de estos componentes, en la que distintos desarrolladores pueden participar para desplegar un determinado servicio o parte de él. Por ello, en este artículo se presenta una solución para la distribución de código de forma segura usando OpenID y firmas con certificados de clave pública de corta duración. De esta forma, se consigue un compromiso de seguridad que permite distribuir código firmado sin la necesidad de que los desarrolladores dispongan a priori de un certificado específico. Presentamos además algunos detalles acerca de la implementación realizada para hacer realidad este diseño.
3rd CompanionAble Workshop - Future Internet of People, Things and Services (IoPTS) eco-Systems, xxxx, pp. xxxx, December, 2009.
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.
5th International Workshop on Formal Aspects in Security and Trust (FAST’08), LNCS 5491, Springer, pp. 302-315, 2008. DOI
When delegation in real world scenarios is considered, the delegator (the entity that posses the privileges) usually passes the privileges on to the delegatee (the entity that receives the privileges) in such a way that the former looses these privileges while the delegation is effective. If we think of a physical key that opens a door, the privilege being delegated by the owner of the key is opening the door. Once the owner of the key delegates this privilege to another entity, by handing over the key, he is not able to open the door any longer. This is due to the fact that the key is not copied and handed over but handed over to the delegatee. When delegation takes place in the electronic world, the delegator usually retains also the privileges. Thus, both users have them simultaneously. This situation, which in most cases is not a problem, may be undesirable when dealing with certain kind of resources. In particular, if we think of finite resources, those in which the number of users accessing simultaneously is finite, we can not allow that a user delegating his access privilege is also granted access when the delegation if effective. In this paper we propose an approach where each user is delegated an access quota for a resource. If further delegating of the delegated quota occurs, this is subtracted from his quota. That is, when delegating, part of the quota remains with the delegator and another part goes to the delegatee. This allows a more fairly access to the resource. Moreover, we show that this approach can also be applied to any kind of resources by defining appropriate authorization policies.
Fifth International Network Conference (INC’05), pp. 157-164, 2005.
VIII Reunión Española sobre Criptología y Seguridad de la información (VIII RECSI),Madrid, pp. 571-581, Septiembre, 2004.
Este trabajo muestra los detalles de una implementacion prototipo del marco de trabajo de Certificados de Atributos X.509 (Xac), propuesto por la recomendacion ITU-T. La implementacion utiliza como base de la plataforma la librer
International Conference on Infrastructure Security (InfraSec’02), LNCS 2437, Springer-Verlag, pp. 325-337, October, 2002.
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.
3rd ACIS Int. Conf. on Software Engineering, Artificial Intelligence Networking and Parallel/Distributed Computing (SNPD’02), pp. 157-163, Junio, 2002.
Interaction of organizations and their clients by using the Internet can produce meaningful benefits in the accessibility, efficiency and availability of documents, regardless of time and location. However, some types of problems hinder a higher degree of communication. This paper presents some of the results of a Research Project that focuses on the influence of typical open networks risks in electronic interactions and on the need of creating software tools to manage electronic versions of the paper-based forms, as this is the traditional way of interaction through the Web.
IEEE International Workshop on Electronic Government (in DEXA’00), IEEE Press, pp. 362-365, 2000.
11th International Conference on Database and Expert Systems Applications (DEXA’00), LNCS 1873, Springer, pp. 929-938, September, 2000.
Public-key cryptography is fast becoming the foundation for those applications that require security and authentication in open networks. But the widespread use of a global public-key cryptosystem requires that public-key certificates are always available and up-to-date. Problems associated to digital certificates management, like storage, retrieval, maintenance, and, specially, revocation, require special procedures that ensure reliable features because of the critical significance of inaccuracies. Most of the existing systems use a Certificate Revocation List, a repository of certificates that have been revoked before their expiration date. The need to access CRLs in order to check certificate revocations becomes a performance handicap. Furthermore, they introduce a source of vulnerability in the whole security infrastructure, as it is impossible to produce a new CRL each time a revocation takes place. This paper introduces an alternative for the storage of digital certificates that avoids the use of CRLs. The system is designed to provide a distributed management of digital certificates by using Certification Authorities that, while being part of a whole Public-Key Infrastructure, operate over local certificates databases. Communication protocols between local databases have been designed to minimize network traffic without a lack of security and efficiency.
5th Intern. Conf. on Computer Aided Systems Theory and Technology (EUROCAST’97), pp. 183-189, February, 1997.
This paper is a first approach to the use of artificial neural networks as a tool to estimate the orientation of an object, and is mainly directed towards industrial applications. The capability of neural networks to generalise is a key element in the calculation of an object’s orientation. In this sense, a neural network can identify the angle of a part never seen before. To evaluate the efficiency of this method we have performed a series of tests with the different parts used in a car assembly line.