Distributed systems like e-commerce and e-market places, peer-to-peer networks, social networks, and mobile ad hoc networks require cooperation among the participating entities to guarantee the formation and sustained existence of network services. The reliability of interactions among anonymous entities is a significant issue in such environments. The distributed entities establish connections to interact with others, which may include selfish and misbehaving entities and result in bad experiences. Therefore, trustworthiness evaluation using trust management techniques has become a significant issue in securing these environments to allow entities decide on the reliability and trustworthiness of other entities, besides it helps coping with defection problems and stimulating entities to cooperate. Recent models on evaluating trustworthiness in distributed systems have heavily focused on assessing trustworthiness of entities and isolate misbehaviours based on single trust metrics. Less effort has been put on the investigation of the subjective nature and differences in the way trustworthiness is perceived to produce a composite multidimensional trust metrics to overcome the limitation of considering single trust metric. In the light of this context, this thesis concerns the evaluation of entities’ trustworthiness by the design and investigation of trust metrics that are computed using multiple properties of trust and considering environment. Based on the concept of probabilistic theory of trust management technique, this thesis models trust systems and designs cooperation techniques to evaluate trustworthiness in mobile ad hoc networks (MANETs). A recommendation based trust model with multi-parameters filtering algorithm, and multidimensional metric based on social and QoS trust model are proposed to secure MANETs. Effectiveness of each of these models in evaluating trustworthiness and discovering misbehaving nodes prior to interactions, as well as their influence on the network performance has been investigated. The results of investigating both the trustworthiness evaluation and the network performance are promising.

The first industrial revolution moved from farming to factory through the development ofthe steam engine. The Second arose through the innovation of electricity and the thirdindustrial revolution moved from analogue technology to digital technology. The latestindustry trend is called industry 4.0, whose vision is to create automated factories. Industry4.0 refers to create smart factories, where physical objects may communicate with eachother to solve different kind of problems. This new technology entails different changes forcompanies, there among other things; the role of human beings will be affected in one oranother way.This thesis has examined an industrial company, which strives to develop their businesstowards industry 4.0. The purpose of the study was to review an ongoing implementationof IoT, focusing on understanding different actors' perspectives on the emerging technology.On this basis several of possibilities and difficulties were identified, which companies needto consider in the future when developing towards industry 4.0.The result of the study describes the difference between different actors' perspectives, whichin the future will have to be discussed in order to find a balance in the IoT-environment. Byexamining an ongoing implementation of IoT, a checklist consisting of key componentswere identified. This checklist may be useful for companies with / Den första industriella revolutionen uppkom vid ångmaskinens framgång, den andra genomelektricitet och den tredje utvecklades med hjälp av IT. Den senaste trenden inom industrinkallas Industri 4.0, vars vision syftar till att skapa automatiserade fabriker. Den nya teknikenkommer inte att utvecklas över en natt och det finns ett flertal faktorer vilka behöverundersökas för att lyckas ta stegen mot visionen. Industri 4.0 medför olika förändringar förföretagen där bland annat människans roll inom verksamheten kommer att påverkas.Studien har genomförts mot ett medelstort industriföretag, vilket strävar efter att utvecklasin verksamhet mot industri 4.0. Författarna har tidigare samarbetat med industriföretagetoch konsultbyrån. Tillsammans utvecklar de en plattform mot Internet of Things (IoT) föratt ta första steget mot en uppkopplad verksamhet. Syftet med studien var att granska enpågående implementering av IoT med fokus på att förstå olika aktörers perspektiv på denframväxande tekniken. Med den utgångspunkten identifierades olika möjligheter ochproblem företagen kommer att behöva ta hänsyn till.Studiens resultat belyser skillnaden mellan olika aktörers perspektiv vilket i framtidenkommer att behöva diskuteras för att hitta en balans. Eftersom studien granskade enpågående implementering identifierades dessutom ett arbetssätt bestående av viktigakomponenter för företag med visionen att börja utveckla sin verksamhet mot industri 4.0visionen.

Context: Due to popularization of internet and e-commerce, more and more people getting involved in online shopping market. A large number of companies have been transferred to the internet where online customers have been increased due to easy access. The online business facilitates people to communicate without knowing each other. The e-commerce systems are the combination of commerce behavior and internet technologies. Therefore, trust aspects are positive elements in buyer-seller transactions and a potential source of competitive e-commerce industry. There are two different approaches to handle the trust. The first approach has a solid authentication set of rules where decisions are made on some digital or logical rules called policy based trust mechanism. The second approach is a decentralized trust approach where reputation assembled and shared in distributed environment called reputation based trust mechanism. Objectives: In this thesis, the strengths and weaknesses of policy and reputation based trust mechanisms have been identified through systematic literature review and industrial interviews. Furthermore, the process of integrated trust mechanism has been proposed. Methods: The integrated trust mechanism is proposed through mapping process, weakness of one mechanism with the strength of other. The proposed integrated trust mechanism was validated by conducting experiment with buyer/seller scenario in auction system. Conclusion: The analysis of collected results indicated that proposed integrated trust mechanism improved the trust of buyer against eBay and Tradera. At the end, we have discussed some key points that may affect trust relationship between seller and buyer. Furthermore, there is a need for further validation of proposed trust mechanism in auction system/e-commerce industry.

Les communautés virtuelles sont des systèmes sociotechniques dans lesquels des entités (humaines et/ou artificielles) répartis à travers le monde se réunissent autour d’intérêts et/ou d’objectifs communs. Afin de réaliser ces objectifs, les membres de la communauté doivent collaborer en partageant leurs ressources et/ou connaissances. Or, toute collaboration comporte une part de risque dans la mesure où les membres peuvent se comporter de manière non coopérative ou malveillante. Dans de tels contextes, où les mécanismes de sécurité standard ne suffissent plus, la confiance est rapidement devenue un facteur déterminant lors de la prise de décision. Le travail présenté dans cette thèse s’attaque à la problématique de la gestion de la confiance dans les communautés virtuelles ouvertes et décentralisées. Pour cela, nous avons proposé une infrastructure de gestion de la confiance adaptative et conforme socialement (ASC-TMS). L’aspect novateur de ce système réside dans sa faculté à exhiber des propriétés sociales et adaptatives. L’aspect social du ASC-TMS fait référence à la capacité de notre système à prendre des décisions qui soient sûres non seulement pour l’individu mais également et surtout pour les autres membres de la communauté. Par ailleurs, l’aspect adaptatif du système fait référence à la capacité du système à prendre des décisions qui soient en parfaite adéquation avec l’environnement dans lequel ces décisions sont prises. Ainsi, cette thèse constitue une nouvelle étape vers l’automatisation de l’évaluation de la confiance en assistant les membres des communautés virtuelles ouvertes et décentralisées dans leur prise de décision. Le système a été implémenté et déployé en utilisant la plateforme de développement multi-agent JaCaMo. Nous avons également illustré l’applicabilité de notre approche sur un scénario réel de communauté virtuelle d’innovation ouverte. Enfin, nous avons évalué notre système expérimentalement en utilisant la plateforme de simulation multi-agent Repast. Les résultats obtenus montrent que l’utilisation de notre système avait un impact positif sur la dynamique des communautés dans lesquels il est a été utilisé. / Virtual communities (VCs) are socio-technical systems wherein distributed individuals (human and/or artificial) are grouped together around common objectives and goals. In such systems, participants are massively collaborating with each other’s by sharing their private resources and knowledge. A collaboration always bears the risk that one partner exhibits uncooperative or malicious behaviour. Thus, trust is a critical issue for the success of such systems. The work presented in this dissertation addresses the problem of trust management in open and decentralised virtual communities (VCs). To address this problem, we proposed an Adaptive and Socially-Compliant Trust Management System (ASC-TMS). The novelty of ASC-TMS lies in its ability to exhibit social-awareness and context-awareness features. Social-awareness refers to the ability of the trust management system (TMS) to handle the social nature of VCs by making trust evaluations that are collectively harmful, while context-awareness refers to the ability of the system to handle the dynamic nature of VCs by making trust evaluations that are always in adequacy with the context in which these evaluations are undertaken. Thus, the contributions made in this thesis constitute an additional step towards the automation of trust assessment. We provided accordingly a novel trust management system that assists members of open and decentralised virtual communities in their trust decisions. The system has been implemented and deployed using the JaCaMo multi-agent platform. We illustrated also the applicability of on a real life open innovation virtual community scenario. Finally, the ASC-TMS has been experimentally evaluated using the multi-agent based Repast simulation platform. The preliminary results show that the use of our system significantly improves the stability of the virtual communities in which it has been deployed.

Les services de conversation Web en temps réel permettent aux utilisateurs d'avoir des appels audio et vidéo et de transférer directement des données sur Internet. Les opérateurs OTT (OTT) tels que Google, Skype et WhatsApp proposent des services de communication économiques avec des fonctionnalités de conversation évoluées. Avec l'introduction de la norme de Web Real Time Communication (WebRTC), n'importe quelle page Web peut désormais offrir des services d'appel. WebRTC est utilisé comme technologie sous-jacente pour déployer de nouvelles plateformes de communication centrées sur le Web. Ces plates-formes visent à offrir de nouvelles méthodes modernes de contact et de communication sur le web. Contrairement aux réseaux de télécommunication traditionnels, les identités sur le Web sont basées sur des profils d'utilisateur et des informations d'identification auto-affirmés. Par conséquent, les opérateurs Web sont incapables d'assurer la fiabilité de leurs abonnés. Les services de communication Web restent exposés à des menaces dans lesquelles le contexte social entre les parties communicantes est manipulé. Un attaquant se définit comme une entité de confiance pour transmettre de fausses informations à l'utilisateur ciblé. Les menaces typiques contre le contexte social comprennent la fausse représentation d'identité, l’hameçonnage, le spam et la distribution illégale de contenu. Afin d'assurer la sécurité sur les services de communication Web, la confiance entre les parties communicantes doit être établie. La première étape consiste à permettre aux utilisateurs d'identifier leurs participants communicants afin de savoir avec qui ils parlent. Cependant, l'authentification seule ne peut garantir la fiabilité d'un appelant. De nouvelles méthodes d'estimation de la réputation de l'appelant devraient également être intégrées dans les services d'appel Web. Par conséquent, dans cette thèse, nous présentons un nouveau cadre de confiance qui fournit des informations sur la fiabilité des appelants dans les réseaux de communication Web. Notre approche est organisée en quatre parties. Premièrement, nous décrivons la notion de confiance dans la communication web en temps réel. Un modèle de confiance est présenté pour identifier les relations de confiance nécessaires entre les entités d'un système de communication. Les paramètres requis pour calculer la confiance dans les services de communication Web sont officiellement introduits. Deuxièmement, nous montrons comment les protocoles Single-Sign-On (SSO) peuvent être utilisés pour authentifier les utilisateurs d'une manière Peer-to-Peer (P2P) sans dépendre de leur fournisseur de service. Nous présentons une comparaison entre trois protocoles d'authentification appropriés (OAuth, BrowserID, OpenID Connect). La comparaison montre que OpenID Connect est le meilleur candidat en termes de confidentialité des utilisateurs. Troisièmement, un modèle de calcul de confiance est proposé pour mesurer la fiabilité des appelants dans un réseau de communication. La légitimité et l'authenticité d'un appelant sont calculées à l'aide de recommandations, tandis que la popularité d'un appelant est estimée en utilisant son comportement de communication. Un abonné d'un service de communication sera capable de visualiser la confiance calculée d'autres membres avant d'initier ou d'accepter une demande d'appel. Enfin, la réputation d'un appelant est utilisée pour lutter contre les appels nuisibles générés sur les réseaux de communication. Les appels de nuisance sont décrits comme des appels de spam non sollicités en masse générés sur un réseau de communication à des fins de marketing et de tromperie. Les enregistrements de données d'appel et les commentaires reçus par les parties communicantes sont utilisés pour déterminer la réputation de l'appelant. La réputation évaluée est utilisée pour différencier les spammeurs et les appelants légitimes du réseau / Real-time web conversational services allow users to have audio and video calls over the Internet. Over-The-Top operators such as Google and Facebook offer cost-effective communication services with advanced conversational features. With the introduction of WebRTC standard, any website or web application can now have built-in communication capabilities. WebRTC technology is expected to boost Voice-Over-IP by making it more robust, flexible and accessible. Telco operators also intend to use the underlying technology to offer communication services to their subscribers over the web. Emerging web-centric communication platforms aims to offer modern methods of contacting and communicating over the web. However, web operators are unable to ensure the trustworthiness of their subscribers, since identities are based on self-asserted user profiles and credentials. Thus, they remain exposed to many social threats in which the context between communicating parties is manipulated. An attacker usually misrepresents himself to convey false information to the targeted victim. Typical social threats include phishing, spam, fraudulent telemarketing and unlawful content distribution. To ensure user security over communication networks, trust between communicating parties needs to be established. Communicating participants should be able to verify each other’s identity to be sure of whom they are talking to. However, authentication alone cannot guarantee the trustworthiness of a caller. New methods of estimating caller’s reputation should also be built in web calling services. In this thesis, we present a novel trust framework that provides information about the trustworthiness of callers in web communication networks. Our approach is organized in four parts. Firstly, we describe the notion of trust in real-time web communication services. A trust model approach is presented to formally introduce the trust computation parameters and relationships in a communication system. Secondly, we detail the mechanism of identity provisioning that allows communicating participants to verify each other’s identity in a Peer-to-Peer fashion. The choice of authentication protocol highly impacts user privacy. We showed how OpenID Connect used for Single-Sign-On authentication purposes can be effectively used for provisioning identities while preserving user privacy. Thirdly, a trust computational model is proposed to measure the trustworthiness of callers in a communication network. The legitimacy and genuineness of a caller’s identity is computed using recommendations from members of the network. On the other hand, the popularity of a caller is estimated by analyzing its behavior in the network. Each subscriber will be able to visualize the computed trust of other members before initiating or accepting a call request. Lastly, the reputation of a caller is used to combat nuisance calls generated over communication networks. Nuisance calls are described as unsolicited bulk spam phone calls generated for marketing and deceptive purposes. Caller’s reputation is computed using the diversity of outgoing calls, call duration, recommendations from called participants, reciprocity and repetitive nature of calls. The reputation is used to differentiate between legitimate and nuisance calls generated over the network

Les technologies de l'Internet des objets (IdO) et de l'externalisation des services informatiques ont conduit à l'émergence de nouvelles menace sur la vie privée des utilisateurs. Cependant, l'implémentation des moyens de sécurité traditionnels sur les équipements de l'IdO constitue un premier défi lié aux limites de capacités. D'un autre côté, la délégation du traitement et du stockage des données, nous pose le problème de confiance envers les fournisseurs de service.Dans ce contexte, nous avons proposé une solution de chiffrement qui assure une protection de données centrée sur leurs propriétaires et adaptée à l'environnement contraignant des objets connectés. Ce modèle se base sur le chiffrement par attributs avec externalisation sécurisée et la technologie de la Blockchain. Ensuite, en réponse à la problématique de la confiance et de la sélection du service, nous avons exploré les possibilités offertes par les outils de l'intelligence artificielle. Pour ce faire, nous avons proposé un modèle de filtrage collaboratif basé sur les cartes de Kohonen avec une solution pour détecter les utilisateurs non fiable. / Internet of Things (IoT) and IT service outsourcing technologies have led to the emergence of new threats to users' privacy. However, the implementation of traditional security measures on IoT equipment is a first challenge due to capacity limitations. On the other hand, the offloading of data processing and storage poses the problem of trust in service providers.In this context, we have proposed an encryption solution that provides owner-centric data protection adapted to the constraining environment of IoT. This model is based on attribute-based encryption with secure offloading capability and Blockchain technology. Then, in response to the issue of trust and service selection, we explored the possibilities offered by artificial intelligence tools. To do this, we proposed a collaborative filtering model based on Kohonen maps and efficient solution to detect the untrusted users.

Distributed systems like e-commerce and e-market places, peer-to-peer networks, social networks, and mobile ad hoc networks require cooperation among the participating entities to guarantee the formation and sustained existence of network services. The reliability of interactions among anonymous entities is a significant issue in such environments. The distributed entities establish connections to interact with others, which may include selfish and misbehaving entities and result in bad experiences. Therefore, trustworthiness evaluation using trust management techniques has become a significant issue in securing these environments to allow entities decide on the reliability and trustworthiness of other entities, besides it helps coping with defection problems and stimulating entities to cooperate. Recent models on evaluating trustworthiness in distributed systems have heavily focused on assessing trustworthiness of entities and isolate misbehaviours based on single trust metrics. Less effort has been put on the investigation of the subjective nature and differences in the way trustworthiness is perceived to produce a composite multidimensional trust metrics to overcome the limitation of considering single trust metric. In the light of this context, this thesis concerns the evaluation of entities’ trustworthiness by the design and investigation of trust metrics that are computed using multiple properties of trust and considering environment. Based on the concept of probabilistic theory of trust management technique, this thesis models trust systems and designs cooperation techniques to evaluate trustworthiness in mobile ad hoc networks (MANETs). A recommendation based trust model with multi-parameters filtering algorithm, and multidimensional metric based on social and QoS trust model are proposed to secure MANETs. Effectiveness of each of these models in evaluating trustworthiness and discovering misbehaving nodes prior to interactions, as well as their influence on the network performance has been investigated. The results of investigating both the trustworthiness evaluation and the network performance are promising. / Ministry of Higher Education in Libya and the Libyan Cultural Attaché bureau in London

"Forschung meets Business" - diese Kombination hat in den vergangenen Jahren immer wieder zu zahlreichen interessanten und fruchtbaren Diskussionen geführt. Mit dem Symposium "Sicherheit in Service-orientierten Architekturen" führt das Hasso-Plattner-Institut diese Tradition fort und lud alle Interessenten zu einem zweitägigen Symposium nach Potsdam ein, um gemeinsam mit Fachvertretern aus der Forschung und Industrie über die aktuellen Entwicklungen im Bereich Sicherheit von SOA zu diskutieren. Die im Rahmen dieses Symposiums vorgestellten Beiträge fokussieren sich auf die Sicherheitsthemen "Sichere Digitale Identitäten und Identitätsmanagement", "Trust Management", "Modell-getriebene SOA-Sicherheit", "Datenschutz und Privatsphäre", "Sichere Enterprise SOA", und "Sichere IT-Infrastrukturen". / 'Research meets Business' is the successful concept of the SOA Security Symposia held at the Hasso-Plattner-Institute that has lead to interesting discussions in the community. The SOA Security Symposium 2010 continued this tradition and invited researchers and representatives from the industry to discuss concepts, issues, and solution in the field of SOA Security. The topics presented in the scope of this symposium focused on the security related topics 'Secure Digital Identities and Identity Management', 'Trust Management', 'Model-driven SOA Security', 'Privacy',' Secure Enterprise SOA', and 'Secure IT-Infrastructures'.

I den här studien undersöks tillit inom ledarskap. Studien fokuserar på ledarskap på individnivå, i ett sammanhang av motivation. Undersökningen belyste vilka tolkningar och upplevda erfarenheter som fanns bland chefer i tillämpandet av ett tillitsbaserat ledarskap på en myndighet som Migrationsverket. Ambitionen med studien var att öka förståelsen för vad tillitsbaserat ledarskap är, och för motivationsmiljöns betydelse gällande att utöva tillitsbaserat ledarskap. Studiens syfte var därmed ökad kunskap om hur tillitsbaserat ledarskap och motivationsmiljö kom till uttryck, samt hur de förhöll sig till varandra, i en offentlig organisation. I fråga om teoretiskt ramverk, har Mayer et al. (1995) tillitsmodell, Bringselius (2021) tillitsbaserade ledarskapsteori och Deci och Ryan (2000) självbestämmande teori (SDT) varit vägledande. Som metod har kvalitativa semistrukturerade intervjuer genomförts.  Resultatet har visat att myndighetscheferna tolkade och praktiserade interpersonellt tillitsbaserat ledarskap utifrån tolkningen om tillit som ett förtroende. Förståelsen för depraktiserade tillitsbaserade ledarskapet tillskrevs bland annat att vara sårbar, skapa ett tillåtande arbetsklimat, skapa psykologisk trygghet och inneha ett medborgarfokus samt aspekter av relationellt- och strukturellt tillitsbaserat ledarskap. Chefernas tolkningar skilde sig därmed från den teoretiska förståelsen av tillitens tre komponenter - förmåga, välvilja och integritet.  Resultatet har även visat att cheferna delvis upplevde en hållbar motivationsmiljö i fråga om autonomi, kompetens och tillhörighet. Studien visade därtill att det fanns upplevda hinder i form av hierarki, byråkrati och kontrollerade uppföljningsmetoder och därmed att motivationen påverkade uppfattningarna om det tillitsbaserade ledarskapet. Sammanfattningsvis har denna studie visat vad tillitsbaserat ledarskap och motivationsmiljö är, hur det uppfattas och varför det kan vara av betydelse för en offentlig organisation. / In this research trust has been studied. Trust has been directed towards leadership in a context of motivation. The survey highlighted the interpretations and experiences of a trust-based leadership that existed among managers in an authority such as the Swedish Migration Board. The ambition of the research was to increase the understanding of what trust-based leadership is, and the importance of the motivational environment regarding the trust-based leadership.  The purpose of the research was to increase knowledge about how trust-based leadership and motivational environment were expressed, and how they related to each other, in a public organization. In terms of theoretical framework, Mayer et al. (1995) trust model, Bringselius (2021) trust-based leadership theory and Deci and Ryan (2000) self-determination theory (SDT) have been used as guidance. As a method, qualitative semi-structured interviews were conducted. The results have shown that the managers interpreted and practiced interpersonal trust-based leadership on the interpretation of trust regarding confidence. The understanding of the practiced trust-based leadership was based as being vulnerable, creating a tolerant work climate, creating psychological security and having a citizen focus, as well as aspects of relational and structural trust-based leadership. The managers’ interpretations thus differed from the theoretical understanding of the three components of trust: ability, benevolence and integrity. The results also showed that the managers partly experienced a sustainable motivational environment in terms of autonomy, competence and relatedness. It also showed that there were perceived obstacles of hierarchy, bureaucracy and controlled follow-up methods and that the motivation was influenced regarding the perceptions of trust-based leadership. In summary, this study has shown what trust-based leadership and motivational environment is, how it is perceived and why it can be important for a public organization.

Chaque année, des millions de personnes meurent et beaucoup d'autres subissent des séquelles graves à la suite d'accidents de la route. Malgré une multitude d’initiatives, le nombre de cas mortels et d'accidents graves augmente chaque année en engendrant des problèmes préoccupants à la fois sociaux, économiques et sanitaires. En raison de leur nombre élevé et de l'absence de protection personnelle, plus de la moitié de ces décès concerne les usagers vulnérables (en anglais, vulnerable road users - VRU) regroupant les piétons, cyclistes et motocyclistes. Les appareils mobiles, combinés à la technologie de Fog Computing (ou informatique géodistribuée, ou même informatique en brouillard), représentent une solution réaliste à court terme pour les protéger en les avertissant de l’imminence d'un accident de circulation. L’omniprésence des appareils mobiles et leurs capacités de calcul élevées font de ces appareils un élément important à considérer dans les solutions de sécurité routière. Le Fog Computing offre des fonctionnalités adaptées aux applications de sécurité routière, puisqu’il s’agit d’une extension du Cloud Computing permettant de rapprocher les services informatiques, le stockage et le réseau au plus près des utilisateurs finaux. Par conséquent, dans cette thèse, nous proposons une architecture réseau sans infrastructure supplémentaire (PV-Alert) pour des fins de sécurité routière et reposant uniquement sur les appareils mobiles des VRU et des conducteurs sur la route avec l’aide du concept de Fog Computing. Les données géographiques et cinématiques de ces appareils sont collectées et envoyées périodiquement au serveur fog situé à proximité. Le serveur fog traite ces données en exécutant un algorithme de calcul de risque d’accident de circulation et renvoie des notifications en cas d'accident imminent. L’évaluation de cette architecture montre qu’elle est capable de générer des alertes en temps réel et qu’elle est plus performante que d’autres architectures en termes de fiabilité, d’évolutivité et de latence. / Annually, millions of people die and many more sustain non-fatal injuries because of road traffic crashes. Despite multitude of countermeasures, the number of causalities and disabilities owing to traffic accidents are increasing each year causing grinding social, economic, and health problems. Due to their high volume and lack of protective-shells, more than half of road traffic deaths are imputed to vulnerable road users (VRUs): pedestrians, cyclists and motorcyclists. Mobile devices combined with fog computing can provide feasible solutions to protect VRUs by predicting collusions and warning users of an imminent traffic accident. Mobile devices’ ubiquity and high computational capabilities make the devices an important components of traffic safety solutions. Fog computing has features that suits to traffic safety applications as it is an extension of cloud computing that brings down computing, storage, and network services to the proximity of end user. Therefore, in this thesis, we have proposed an infrastructure-less traffic safety architecture that depends on fog computing and mobile devices possessed by VRUs and drivers. The main duties of mobile devices are extracting their positions and other related data and sending cooperative awareness message to a nearby fog server using wireless connection. The fog server estimates collision using a collision prediction algorithm and sends an alert message, if an about-to-occur collision is predicted. Evaluation results shows that the proposed architecture is able to render alerts in real time. Moreover, analytical and performance evaluations depict that the architecture outperforms other related road safety architectures in terms of reliability, scalability and latency. However, before deploying the architecture, challenges pertaining to weaknesses of important ingredients of the architecture should be treated prudently. Position read by mobile devices are not accurate and do not meet maximum position sampling rates traffic safety applications demand. Moreover, continuous and high rate position sampling drains mobile devices battery quickly. From fog computing’s point of view, it confronts new privacy and security challenges in addition to those assumed from cloud computing. For aforementioned challenges, we have proposed new solutions: (i) In order to improve GPS accuracy, we have proposed an efficient and effective two-stage map matching algorithm. In the first stage, GPS readings obtained from smartphones are passed through Kalman filter to smooth outlier readings. In the second stage, the smoothed positions are mapped to road segments using online time warping algorithm. (ii) position sampling frequency requirement is fulfilled by an energy efficient location prediction system that fuses GPS and inertial sensors’ data. (iii) For energy efficiency, we proposed an energy efficient fuzzy logic-based adaptive beaconing rate management that ensures safety of VRUs. (iv) finally, privacy and security issues are addressed indirectly using trust management system. The two-way subjective logic-based trust management system enables fog clients to evaluate the trust level of fog servers before awarding the service and allows the servers to check out the trustworthiness of the service demanders. Engaging omnipresent mobile device and QoS-aware fog computing paradigm in active traffic safety applications has the potential to reduce overwhelming number of traffic accidents on VRUs.