Weaknesses of an Improvement Authentication Scheme using

Recently, Sood-Sarje-Singh proposed an improvement to Liou et al.’s dynamic ID-based remote user authentication scheme using smart cards to prevent impersonation attack, malicious user attack, off-line password guessing attack, and man-in-the-middle attack. However, we demonstrate that Sood et al.’s scheme is still vulnerable to malicious user attack, impersonation attack and steal information from a database attack

Cryptanalysis and improvement of chen-hsiang-shih's remote user authentication scheme using smart cards

Recently, Chen-Hsiang-Shih proposed a new dynamic ID-based remote user authentication scheme. The authors claimed that their scheme was more secure than previous works. However, this paper demonstrates that theirscheme is still unsecured against different kinds of attacks. In order to enhance the security of the scheme proposed by Chen-Hsiang-Shih, a new scheme is proposed. The scheme achieves the following security goals: without verification table, each user chooses and changes the password freely, each user keeps the password secret, mutual authentication, the scheme establishes a session key after successful authentication, and the scheme maintains the user's anonymity. Security analysis and comparison demonstrate that the proposed scheme is more secure than Das-Saxena-Gulati's scheme, Wang et al.'s scheme and Chen-Hsiang-Shih.Peer ReviewedPostprint (published version

Security improvement of two dynamic ID-based authentication schemes by Sood-Sarje-Singh

In 2010, Sood-Sarje-Singh proposed two dynamic ID-based remote user authentication schemes. The first scheme is a security improvement of Liao et al.’s scheme and the second scheme is a security improvement of Wang et al.’s scheme. In both cases, the authors claimed that their schemes can resist many attacks. However, we find that both schemes have security flaws. In addition, their schemes require a verification table and time-synchronization, making the schemes unfeasible and unsecured for electronic services. In order to remedy the security flaws of Sood et al.’s schemes, we propose a robust scheme which resists the well-known attacks and achieves all the desirable security goals.Peer ReviewedPostprint (published version

Reducing the computational cost of the authentication process in SET protocol

SET es un protocolo seguro de pago, con tarjeta de crédito, que proporciona un modelo robusto de seguridad para entregar información personal y financiera a través de Internet, basado en la integridad de los datos, su confidencialidad y la autenticación mutua. Sin embargo, las partes involucradas en una transacción deben llevar a cabo diversas operaciones criptográficas, lo que puede ser un problema cuando se usan dispositivos móviles con baja capacidad de almacenamiento y procesamiento. Este artículo muestra como se puede reducir el coste computacional de SET, mediante el uso de otro protocolo llamado TRUTHC en conjunto con una Infraestructura de Clave Pública (PKI). Los resultados muestran que, usando TRUTHC, el tiempo total de ejecución puede ser reducido un 3% desde el punto de vista del cliente. Esta reducción se mantiene aunque aumente la longitud del camino de certificación.Postprint (published version

A machine learning based Distributed Congestion Control Protocol for multi-hop wireless networks

The application areas of multi-hop wireless networks are expected to experience sustained growth in the next years. This growth will be further supported by the current possibility of providing low-cost communication capabilities to any device. One of the main issues to consider with this type of networks is congestion control, that is, avoiding an excessive volume of data traffic that could lead to a loss of performance. In this work, a distributed congestion control mechanism is proposed for generic multi-hop networks. Different categories of data traffic are taken into account, each of them with different quality of service requirements. The mechanism is based on machine learning techniques, specifically, the CatBoost algorithm that uses gradient boosting on decision trees. The obtained decision trees are used to predict whether the packets to be transmitted over the network will reach their destination on time or not. This prediction will be made based on the network load state, which will be quantified by means of two parameters: the utilization factor of the different transmission channels, and the occupancy of the buffers of the network nodes. To make the values of these parameters available to all nodes in the network, an appropriate dissemination protocol has also been designed. Besides, a method to assign different transmission priorities to each traffic category, based on the estimation of the network resources required at any time, has also been included. The complete system has been implemented and evaluated through simulations, which show the correct functionality and the improvements obtained in terms of packet delivery ratio, network transit time, and traffic differentiation.Peer ReviewedPostprint (published version

SISCOM: smart services for information systems and communication networks

The SISCOM (Smart Services for Information Systems and Communication Networks) research group focuses on technologies that make it possible to provide intelligent services for information services and communication networks. We teach and do research in topics related to privacy, performance evaluation of networks, wireless adhoc and mesh networks, design of routing protocols, among others. Our research activities are funded by public research projects granted by the Spanish Government and the European Commission.Peer ReviewedPostprint (published version

Definición de un sistema global de información en materia de discapacidad en la universidad : Observatorio Universidad y Discapacidad

El estudio que se presenta a continuación aporta las reflexiones necesarias para empezar a trabajar en la consecución de un sistema de información que permita recopilar los datos estadísticos necesarios para extraer el conocimiento sobre la evolución del sistema universitario español. Demuestra la viabilidad legal, académica y técnica del sistema sin dudas ni lagunas. Aporta las especificaciones necesarias para su implementación. Y, finalmente, pone en manos de la voluntad la necesidad de su creación.Peer ReviewedPostprint (published version

INRISCO: INcident monitoRing in Smart COmmunities

Major advances in information and communication technologies (ICTs) make citizens to be considered as sensors in motion. Carrying their mobile devices, moving in their connected vehicles or actively participating in social networks, citizens provide a wealth of information that, after properly processing, can support numerous applications for the benefit of the community. In the context of smart communities, the INRISCO [1] proposal intends for (i) the early detection of abnormal situations in cities (i.e., incidents), (ii) the analysis of whether, according to their impact, those incidents are really adverse for the community; and (iii) the automatic actuation by dissemination of appropriate information to citizens and authorities. Thus, INRISCO will identify and report on incidents in traffic (jam, accident) or public infrastructure (e.g., works, street cut), the occurrence of specific events that affect other citizens' life (e.g., demonstrations, concerts), or environmental problems (e.g., pollution, bad weather). It is of particular interest to this proposal the identification of incidents with a social and economic impact, which affects the quality of life of citizens.This work was supported in part by the Spanish Government through the projects INRISCO under Grant TEC2014-54335-C4-1-R, Grant TEC2014-54335-C4-2-R, Grant TEC2014-54335-C4-3-R, and Grant TEC2014-54335-C4-4-R, in part by the MAGOS under Grant TEC2017-84197-C4-1-R, Grant TEC2017-84197-C4-2-R, and Grant TEC2017-84197-C4-3-R, in part by the European Regional Development Fund (ERDF), and in part by the Galician Regional Government under agreement for funding the Atlantic Research Center for Information and Communication Technologies (AtlantTIC)

Spatiotemporal Characteristics of the Largest HIV-1 CRF02_AG Outbreak in Spain: Evidence for Onward Transmissions

Background and Aim: The circulating recombinant form 02_AG (CRF02_AG) is the predominant clade among the human immunodeficiency virus type-1 (HIV-1) non-Bs with a prevalence of 5.97% (95% Confidence Interval-CI: 5.41–6.57%) across Spain. Our aim was to estimate the levels of regional clustering for CRF02_AG and the spatiotemporal characteristics of the largest CRF02_AG subepidemic in Spain.Methods: We studied 396 CRF02_AG sequences obtained from HIV-1 diagnosed patients during 2000–2014 from 10 autonomous communities of Spain. Phylogenetic analysis was performed on the 391 CRF02_AG sequences along with all globally sampled CRF02_AG sequences (N = 3,302) as references. Phylodynamic and phylogeographic analysis was performed to the largest CRF02_AG monophyletic cluster by a Bayesian method in BEAST v1.8.0 and by reconstructing ancestral states using the criterion of parsimony in Mesquite v3.4, respectively.Results: The HIV-1 CRF02_AG prevalence differed across Spanish autonomous communities we sampled from (p < 0.001). Phylogenetic analysis revealed that 52.7% of the CRF02_AG sequences formed 56 monophyletic clusters, with a range of 2–79 sequences. The CRF02_AG regional dispersal differed across Spain (p = 0.003), as suggested by monophyletic clustering. For the largest monophyletic cluster (subepidemic) (N = 79), 49.4% of the clustered sequences originated from Madrid, while most sequences (51.9%) had been obtained from men having sex with men (MSM). Molecular clock analysis suggested that the origin (tMRCA) of the CRF02_AG subepidemic was in 2002 (median estimate; 95% Highest Posterior Density-HPD interval: 1999–2004). Additionally, we found significant clustering within the CRF02_AG subepidemic according to the ethnic origin.Conclusion: CRF02_AG has been introduced as a result of multiple introductions in Spain, following regional dispersal in several cases. We showed that CRF02_AG transmissions were mostly due to regional dispersal in Spain. The hot-spot for the largest CRF02_AG regional subepidemic in Spain was in Madrid associated with MSM transmission risk group. The existence of subepidemics suggest that several spillovers occurred from Madrid to other areas. CRF02_AG sequences from Hispanics were clustered in a separate subclade suggesting no linkage between the local and Hispanic subepidemics

TOMIN: trustworthy mobile cash with expiration-date attached

Los sistemas de pago móvil en línea basados ​​en efectivo móvil brindan privacidad a los clientes y son factibles para escenarios de punto de venta real, punto de venta virtual y comercio móvil de persona a persona. El comerciante no realiza operaciones complejas y el banco verifica la validez del efectivo móvil antes de que el comerciante entregue el producto. El banco debe almacenar el efectivo móvil gastado en una base de datos para evitar un ataque de doble gasto. En este trabajo, proponemos un esquema de efectivo móvil eficiente en el que el cliente adjunta la fecha de vencimiento y la fecha de depósito. Esta propiedad reduce el tamaño de la base de datos del banco y el cliente debe gastar el efectivo móvil antes del vencimiento. Además, el cliente adjunta la identidad del comerciante al efectivo móvil en la fase de depósito. El esquema requiere un bajo costo computacional y es adecuado para dispositivos móviles.Online mobile payment systems based on mobile cash provide privacy to customers and are feasible for real point of sale, virtual point of sale, and person-to-person mobile commerce scenarios. The merchant does not perform complex operations and the bank verifies the validity of the mobile cash before the merchant delivers the product. The bank must store the mobile cash spent in a database to prevent a double spending attack. In this paper, we propose an efficient mobile cash scheme in which the customer attaches the expiration date and deposit date. This property reduces the size of the bank’s database and the customer must spend the mobile cash before expiry. Moreover, the customer attaches the merchant’s identity into the mobile cash in the deposit phase. The scheme requires low computational cost and is suitable for mobile device