Computer and Security, vol. 29, elsevier, pp. 501-514, 2010. DOI (I.F.: 0.889)
Network and device heterogeneity, nomadic mobility, intermittent connectivity and, more generally, extremely dynamic operating conditions, are major challenges in the design of security infrastructures for pervasive computing. Yet, in a ubiquitous computing environment, limitations of traditional solutions for authentication and authorization can be overcome with a pervasive public key infrastructure (pervasive-PKI). This choice allows the validation of credentials of users roaming between heterogeneous networks, even when global connectivity is lost and some services are temporarily unreachable. Proof-of-concept implementations and testbed validation results demonstrate that strong security can be achieved for users and applications through the combination of traditional PKI services with a number of enhancements like: (i) dynamic and collaborative trust model, (ii) use of attribute certificates for privilege management, and (iii) modular architecture enabling nomadic mobility and enhanced with reconfiguration capabilities.
Journal of Information Security and Applications, vol. 61, no. 102916, Elsevier, 09/2021. DOI (I.F.: 3.872)
Computers & Security, vol. 29, no. 2, pp. 167 - 179, 2010. DOI (I.F.: 0.889)
Certified electronic mail is an added value to traditional electronic mail. In the definition of this service some differences arise: a message in exchange for a reception proof, a message and a non repudiation of origin token in exchange for a reception proof, etc. It greatly depends on whether we want to emulate the courier service or improve the service in the electronic world. If the definition of the service seems conflictive, the definition of the properties and requirements of a good certified electronic mail protocol is even more difficult. The more consensuated features are the need of a fair exchange and the existence of a trusted third party (TTP). Each author chooses the properties that considers the most important, and many times the list is conditioned by the proposal. Which kind of TTP must be used? Must it be verifiable, transparent and/or stateless? Which features must the communication channel fulfil? Which temporal requirements must be established? What kind of fairness is desired? What efficiency level is required? Are confidentiality or transferability of the proofs compulsory properties? In this paper we collect the definitions, properties and requirements related with certified electronic mail. The aim of the paper is to create a clearer situation and analyze how some properties cannot be achieved simultaneously. Each protocol designer will have to decide which properties are the most important in the environment in where the service is to be deployed.
Human-centric Computing and Information Sciences, vol. 10, no. 50, Springer, 12/2020. DOI (I.F.: 5.9)
The Internet of Things (IoT) is a paradigm that permits smart entities to be interconnected anywhere and anyhow. IoT opens new opportunities but also rises new issues.
In this dynamic environment, trust is useful to mitigate these issues. In fact, it is important that the smart entities could know and trust the other smart entities in order to collaborate with them.
So far, there is a lack of research when considering trust through the whole System Development Life Cycle (SDLC) of a smart IoT entity.
In this paper, we suggest a new approach that considers trust not only at the end of the SDLC but also at the start of it. More precisely, we explore the modeling phase proposing a model-driven approach extending UML and SysML considering trust and its related domains, such as security and privacy.
We propose stereotypes for each diagram in order to give developers a way to represent trust elements in an effective way.
Moreover, we propose two new diagrams that are very important for the IoT: a traceability diagram and a context diagram.
This model-driven approach will help developers to model the smart IoT entities according to the requirements elicited in the previous phases of the SDLC.
These models will be a fundamental input for the following and final phases of the SDLC.
International Journal of Information Security, Springer, 2020. DOI (I.F.: 1.988)
Nowadays, smart home devices like Amazon Echo and Google Home have reached mainstream popularity.
Being in the homes of users, these devices are intrinsically intrusive, being able to access details such as users' name, gender, home address, calendar appointments and others.
There are growing concerns about indiscriminate data collection and invasion of user privacy in smart home devices, but studies show that perceived benefits are exceeding perceived risks when it comes to consumers.
As a result, consumers are placing a lot of trust in these devices, sometimes without realizing it.
Improper trust assumptions and security controls can lead to unauthorized access and control of the devices, which can result in serious consequences.
In this paper, we explore the behaviour of devices such as Amazon Echo and Google Home in a smart home setting with respect to trust relationships and propose a trust model to improve these relationships among all the involved actors.
We have evaluated how trust was built and managed from the initial set up phase to the normal operation phase, during which we performed a number of interaction tests with different types of users (i.e. owner, guests).
As a result, we were able to assess the effectiveness of the provided security controls and identify potential relevant security issues. In order to address the identified issues, we defined a trust model and propose a solution based on it for further securing smart home systems.
International Journal of Information Security , Springer, pp. 111-127, 01/2020, 2019. DOI (I.F.: 1.494)
The Internet of Things (IoT) is an environment of interconnected entities, which are identifiable, usable and controllable via the Internet. Trust is useful for a system such as the IoT as the entities involved would like to know how the other entities they have to interact with are going to perform.
When developing an IoT entity, it will be desirable to guarantee trust during its whole life cycle. Trust domain is strongly dependent on other domains such as security and privacy.
To consider these domains as a whole and to elicit the right requirements since the first phases of the System Development Life Cycle (SDLC) is a key point when developing an IoT entity.
We emphasize on the importance of the concept of traceability. This property permits to connect all the elicited requirements guaranteeing more control on the whole requirements engineering process.
Computer Standards & Interfaces, Special Issue on Security in Information Systems, vol. 36, issue 4, Elsevier, pp. 792-800, 2014. DOI (I.F.: 0.879)
Trust is an essential feature of any system where entities have to collaborate among them. Trust can assist entities making decisions about what is the best entity for establishing a certain collaboration. It would be desirable to simulate behaviour of users as in social environments where they tend to establish relationships or to trust users who have common interests or share some of their opinions, i.e., users who are similar to them to some extent. Thus, in this paper we first introduce the concept of context similarity among entities and from it we derive a similarity network which can be seen as a graph. Based on this similarity network we dene a trust model that allows us also to establish trust along a path of entities. A possible applications of our model are proximity-based trust establishment. We validate our model in this scenario.
Information Sciences, vol. 396, Elsevier, pp. 72-82, 2017. DOI (I.F.: 4.305)
The Internet of Things (IoT) is a paradigm based on the interconnection of everyday objects. It is expected that the ‘things’ involved in the IoT paradigm will have to interact with each other, often in uncertain conditions. It is therefore of paramount importance for the success of IoT that there are mechanisms in place that help overcome the lack of certainty. Trust can help achieve this goal. In this paper, we introduce a framework that assists developers in including trust in IoT scenarios. This framework takes into account trust, privacy and identity requirements as well as other functional requirements derived from IoT scenarios to provide the different services that allow the inclusion of trust in the IoT.
Journal of Automated Reasoning, vol. 34, Springer, pp. 295-321, 2005. DOI (I.F.: 0.875)
First-order temporal logic, the extension of first-order logic with operators dealing with time, is a powerful and expressive formalism with many potential applications. This expressive logic can be viewed as a framework in which to investigate problems specified in other logics. The monodic fragment of first-order temporal logic is a useful fragment that possesses good computational properties such as completeness and sometimes even decidability. Temporal logics of knowledge are useful for dealing with situations where the knowledge of agents in a system is involved. In this paper we present a translation from temporal logics of knowledge into the monodic fragment of first-order temporal logic. We can then use a theorem prover for monodic first-order temporal logic to prove properties of the translated formulas. This allows problems specified in temporal logics of knowledge to be verified automatically without needing a specialized theorem prover for temporal logics of knowledge. We present the translation, its correctness, and examples of its use.