Dynamic infrastructure for federated identity management in open environments

Centralized identity management solutions were created to deal with user and data security where the user and the systems they accessed were within the same network or domain of control. Nevertheless, the decentralization brought about by the integration of the Internet into every aspect of life is leading to an increasing separation of the user from the systems requiring access. Identity management has been continually evolving in order to adapt to the changing systems, and thus posing new challenges. In this sense, the challenges associated with cross-domain issues have given rise to a new approach of identity management, called Federated Identity Management (FIM), because it removes the largest barriers for achieving a common understanding. Due to the importance of the federation paradigm for online identity management, a lot of work has been done so far resulting in a set of standards and specifications. According to them, under the FIM paradigm a person’s electronic identity stored across multiple distinct domains can be linked, shared and reused. This concept allows interesting use-cases, such as Single Sign-on (SSO), which allows users to authenticate at a single service and gain access to multiple ones without providing additional information. But also provides means for cross-domain user account provisioning, cross-domain entitlement management and cross-domain user attribute exchange. However, for the federated exchange of user information to be possible in a secure way, a trust relationship must exist between the separated domains. The establishment of these trust relationships, if addressed in the federation specifications, is based on complex agreements and configurations that are usually manually set up by an administrator. For this reason, the “internet-like” scale of identity federations is still limited. Hence, there is a need to move from static configurations towards more flexible and dynamic federations in which members can join and leave more frequently and trust decisions can be dynamically computed on the fly. In this thesis, we address this issue. The main goal is contributing to improve the trust layer in FIM in order to achieve dynamic federation. And for this purpose, we propose an architecture that extends current federation systems. The architecture is based on two main pillars, namely a reputation-based trust computation module, and a risk assessment module. In regard to trust, we formalize a model to compute and represent trust as a number, which provides a basis for easy implementation and automation. It captures the features of current FIM systems and introduces new dimensions to add flexibility and richness. The model includes the definition of a trustworthiness metric, detailing the evidences used, and how they are combined to obtain a quantitative value. Basically, authentication information is merged with behavior data, i.e., reputation or history of interactions. In order to include reputation data in the model we contributed with the definition of a generic protocol to exchange reputation information between FIM entities, and its integration with the most widely deployed specification, i.e., Security Assertion Markup Language (SAML). In regard to risk, we define an assessment model that allow entities to calculate how much risk is involved in transacting with another entity according to its configuration, policies, operation rules, cryptographic algorithms, etc. The methodology employed to define the risk model consists of three steps. Firstly, we design a taxonomy to capture the different aspects of a relationship in FIM that may contribute to risk. Secondly, based on the taxonomy and aiming at developing a computational model, we propose a set of metrics as a basis to quantify risk. Finally, we describe how to combine the metrics into a meaningful risk figure by using the Multiattribute Utility Theory (MAUT) methodology, which has been applied and adapted to define the risk aggregation model. Furthermore, an also under the MAUT theory, we propose a fuzzy aggregation system to combine trust and risk into a final value that is the basis for dynamic federation decisions. Formal validation of the above mentioned ideas has been carried out. The risk assessment and decision making are analytically validated ensuring their correct behavior, the reputation protocol included in the trust management proposal is tested through simulations, and the architecture is verified through the development of prototypes. In addition, dissemination activities were performed in projects, journals and conferences. Summarizing, the contributions here constitute a step towards the realization of dynamic federation, based on the flexibilization of the underlying trust frameworks. --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Históricamente el diseño de soluciones de gestión de identidad centralizada ha estado orientado a proteger la seguridad de usuarios y datos en entornos en los que tanto los usuarios como los sistemas se encuentran en la misma red o dominio. Sin embargo, la creciente descentralización acaecida al integrar Internet en muchos aspectos de la vida cotidiana está dando lugar a una separación cada vez mayor entre los usuarios y los sistemas a los que acceden. La gestión de identidad ha ido evolucionando para adaptarse a estos cambios, dando lugar a nuevos e interesantes retos. En este sentido, los retos relacionados con el acceso a diferentes dominios han dado lugar a una nueva aproximación en la gestión de identidad conocida como Federación de Identidad o Identidad Federada. Debido a la importancia de este paradigma, se ha llevado a cabo un gran trabajo que se refleja en la definición de varios estándares y especificaciones. De acuerdo con estos documentos, bajo el paradigma de identidad federada, la identidad digital de un usuario almacenada en múltiples dominios diferentes puede ser enlazada, compartida y reutilizada. Este concepto hace posibles interesantes casos de uso, tales como el Single Sign-on (SSO), que permite a un usuario autenticarse una sola vez en un servicio y obtener acceso a múltiples servicios sin necesidad de proporcionar información adicional o repetir el proceso. Pero además, también se proporcionan mecanismos para muchos otros casos, como el intercambio de atributos entre dominios o la creación automática de cuentas a partir de la información proporcionada por otro dominio. No obstante, para que el intercambio de información personal del usuario entre dominios federados se pueda realizar de forma segura, debe existir una relación de confianza entre dichos dominios. Pero el establecimiento de estas relaciones de confianza, a veces ni siquiera recogido en las especificaciones, suele estar basado en acuerdos rígidos que requieren gran trabajo de configuración por parte de un administrador. Por esta razón, la escalabilidad de las federaciones de identidad es todavía limitada. Como puede deducirse, existe una necesidad clara de cambiar los acuerdos estáticos que rigen las federaciones actuales por un modelo más flexible que permita federaciones dinámicas en las que los miembros puedan unirse y marcharse más frecuentemente y las decisiones de confianza sean tomadas dinámicamente on-the-fly. Este es el problema que tratamos en la presente tesis. Nuestro objetivo principal es contribuir a mejorar la capa de confianza en federación de identidad de manera que el establecimiento de relaciones pueda llevarse a cabo de forma dinámica. Para alcanzar este objetivo, proponemos una arquitectura basada en dos pilares fundamentales: un módulo de cómputo de confianza basado en reputación, y un módulo de evaluación de riesgo. Por un lado, formalizamos un modelo para calcular y representar la confianza como un número, lo cual supone una base para una fácil implementación y automatización. El modelo captura las características de los sistemas de gestión de identidad federada actuales e introduce nuevas dimensiones para dotarlos de una mayor flexibilidad y riqueza expresiva. Se lleva a cabo pues una definición de la métrica de confianza, detallando las evidencias utilizadas y el método para combinarlas en un valor cuantitativo. Básicamente, se fusiona la información de autenticación disponible con datos de comportamiento, es decir, con reputación o historia de transacciones. Para la inclusión de datos de reputación en el modelo, contribuimos con la definición de un protocolo genérico que permite el intercambio de esta información entre las entidades de un sistema de gestión de identidad federada, que ha sido además integrado en el estándar más conocido y ampliamente desplegado (Security Assertion Markup Language, SAML). Por otro lado, en lo que se refiere al riesgo, proponemos un modelo que permite a las entidades calcular en cuánto riesgo se incurre al realizar una transacción con otra entidad, teniendo en cuenta su configuración, políticas, reglas de operación, algoritmos criptográficos en uso, etc. La metodología utilizada para definir el modelo de riesgo abarca tres pasos. En primer lugar, diseñamos una taxonomía que captura los distintos aspectos de una relación en el contexto de federación de identidad que puedan afectar al riesgo. En segundo lugar, basándonos en la taxonomía, proponemos un conjunto de métricas que serán la base para cuantificar el riesgo. En tercer y último lugar, describimos cómo combinar las métricas en una cifra final representativa utilizando el método Multiattribute Utility Theory (MAUT), que ha sido adaptado para definir el proceso de agregación de riesgo. Además, y también bajo la metodología MAUT, proponemos un sistema de agregación difuso que combina los valores de riesgo y confianza en un valor final que será el utilizado en la toma de decisiones dinámicas sobre si establecer o no una relación de federación. La validación de todas las ideas mencionadas ha sido llevada a cabo a través del análisis formal, simulaciones, desarrollo e implementación de prototipos y actividades de diseminación. En resumen, las contribuciones en esta tesis constituyen un paso hacia el establecimiento dinámico de federaciones de identidad, basado en la flexibilización de los modelos de confianza subyacentes

'Surprised, Shocked, Worried': User Reactions to Facebook Data Collection from Third Parties

Data collection and aggregation by online services happens to an extent that is often beyond awareness and comprehension of its users. Transparency tools become crucial to inform people, though it is unclear how well they work. To investigate this matter, we conducted a user study focusing on Facebook, which has recently released the "Off-Facebook Activity" transparency dashboard that informs about personal data collection from third parties. We exposed a group of n = 100 participants to the dashboard and surveyed their level of awareness and reactions to understand how transparency impacts users' privacy attitudes and intended behavior. Our participants were surprised about the massive amount of collected data, became significantly less comfortable with data collection, and more likely to take protective measures. Collaterally, we observed that current consent schemes are inadequate. Based on the survey findings, we make recommendations for more usable transparency and highlight the need to raise awareness about transparency tools and to provide easily actionable privacy controls.Comment: Accepted to PETS (Privacy Enhancing Technologies Symposium) 202

Privacy-centered authentication: a new framework and analysis

© 2023 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/The usage of authentication schemes is increasing in our daily life with the ubiquitous spreading Internet services. The verification of user’s identity is still predominantly password-based, despite of being susceptible to various attacks and openly hated by users. Bonneau et al. presented a framework, based on Usability, Deployability, and Security criteria (UDS), to evaluate authentication schemes and find a replacement for passwords. Although the UDS framework is a mature and comprehensive evaluation framework and has been extended by other authors, it does not analyse privacy aspects in the usage of authentication schemes. In the present work, we extend the UDS framework with a privacy category to allow a more comprehensive evaluation, becoming an UDSP framework. We provide a thorough, rigorous assessment of sample authentication schemes, including analyse novel behavioural biometrics. Our work also discusses implementation aspects regarding the new privacy dimension and sketches the prospect of future authentication schemes.Javier Parra-Arnau is the recipient of a “Ramón y Cajal” fellowship (ref. RYC2021–034256-I) funded by the Spanish Ministry of Science and Innovation and the European Union – “NextGenerationEU”/PRTR (Plan de Recuperación, Transformación y Resiliencia). This work was also supported by the Spanish Government under the project “Enhancing Communication Protocols with Machine Learning while Protecting Sensitive Data (COMPROMISE)” PID2020–113795RB-C31, funded by MCIN/AEI/10.13039/501100011033, and through the project “MOBILYTICS” (TED2021–129782B-I00), funded by MCIN/AEI/10.13039/501100011033 and the European Union “NextGenerationEU”/PRTR.Peer ReviewedPostprint (published version

Privacy-Protecting Techniques for Behavioral Data: A Survey

Our behavior (the way we talk, walk, or think) is unique and can be used as a biometric trait. It also correlates with sensitive attributes like emotions. Hence, techniques to protect individuals privacy against unwanted inferences are required. To consolidate knowledge in this area, we systematically reviewed applicable anonymization techniques. We taxonomize and compare existing solutions regarding privacy goals, conceptual operation, advantages, and limitations. Our analysis shows that some behavioral traits (e.g., voice) have received much attention, while others (e.g., eye-gaze, brainwaves) are mostly neglected. We also find that the evaluation methodology of behavioral anonymization techniques can be further improved

Enabling SAML for dynamic identity federation management

Proceedings of: The Second IFIP WG 6.8 Joint Conference, WMNC 2009, Gdansk, Poland, September 9-11, 2009Federation in identity management has emerged as a key concept for reducing complexity in the companies and offering an improved user experience when accessing services. In this sense, the process of trust establishment is fundamental to allow rapid and seamless interaction between different trust domains. However, the problem of establishing identity federations in dynamic and open environments that form part of Next Generation Networks (NGNs), where it is desirable to speed up the processes of service provisioning and deprovisioning, has not been fully addressed. This paper analyzes the underlying trust mechanisms of the existing frameworks for federated identity management and its suitability to be applied in the mentioned environments. This analysis is mainly focused on the Single Sign On (SSO) profile. We propose a generic extension for the SAML standard in order to facilitate the creation of federation relationships in a dynamic way between prior unknown parties. Finally, we give some details of implementation and compatibility issues

FamTV : an architecture for presence-aware personalized television

Since the advent of the digital era, the traditional TV scenario has rapidly evolved towards an ecosystem comprised of a myriad of services, applications, channels, and contents. As a direct consequence, the amount of available information and configuration options targeted at today's end consumers have become unmanageable. Thus, personalization and usability emerge as indispensable elements to improve our content-overloaded digital homes. With these requirements in mind, we present a way to combine content adaptation paradigms together with presence detection in order to allow a seamless and personalized entertainment experience when watching TV.This work has been partially supported by the Community of Madrid (CAM), Spain under the contract number S2009/TIC-1650.Publicad

Improving privacy in identity management systems for health care scenarios

Privacy is a very complex and subjective concept with different meaning to different people. The meaning depends on the context. Moreover, privacy is close to the user information and thus, present in any ubiquitous computing scenario. In the context of identity management (IdM), privacy is gaining more importance since IdM systems deal with services that requires sharing attributes belonging to users’ identity with different entities across domains. Consequently, privacy is a fundamental aspect to be addressed by IdM to protect the exchange of user attributes between services and identity providers across different networks and security domains in pervasive computing. However, problems such as the effective revocation consent, have not been fully addressed. Furthermore, privacy depends heavily on users and applications requiring some degree of flexibility. This paper analyzes the main current identity models, as well as the privacy support presented by the identity management frameworks. After the main limitations are identified, we propose a delegation protocol for the SAML standard in order to enhance the revocation consent within healthcare scenarios.Proyecto CCG10-UC3M/TIC-4992 de la Comunidad Autónoma de Madrid y la Universidad Carlos III de Madri

SuSSo: seamless and ubiquitous single sign-on for cloud service continuity across devices

The great variety of consumer electronic devices with support of wireless communications combined with the emerging Cloud Computing paradigm is paving the way to real anytime/anywhere computing. In this context, many services, such as music or video streaming, are delivered to the clients using Cloud-based providers. However, service continuity when moving across different terminals is still a major challenge. This paper proposes SuSSo, a novel middleware architecture that allows sessions initiated from one device to be seamlessly transferred to a second one, as might be desirable in the enjoyment of long running media.Publicad

A metric-based approach to assess risk for "on cloud" federated identity management

The cloud computing paradigm is set to become the next explosive revolution on the Internet, but its adoption is still hindered by security problems. One of the fundamental issues is the need for better access control and identity management systems. In this context, Federated Identity Management (FIM) is identified by researchers and experts as an important security enabler, since it will play a vital role in allowing the global scalability that is required for the successful implantation of cloud technologies. However, current FIM frameworks are limited by the complexity of the underlying trust models that need to be put in place before inter-domain cooperation. Thus, the establishment of dynamic federations between the different cloud actors is still a major research challenge that remains unsolved. Here we show that risk evaluation must be considered as a key enabler in evidencebased trust management to foster collaboration between cloud providers that belong to unknown administrative domains in a secure manner. In this paper, we analyze the Federated Identity Management process and propose a taxonomy that helps in the classification of the involved risks in order to mitigate vulnerabilities and threats when decisions about collaboration are made. Moreover, a set of new metrics is defined to allow a novel form of risk quantification in these environments. Other contributions of the paper include the definition of a generic hierarchical risk aggregation system, and a descriptive use-case where the risk computation framework is applied to enhance cloud-based service provisioning.This work was supported in part by the Spanish Ministry of Science and Innovation under the project CONSEQUENCE (TEC2010-20572-C02-01).Publicad