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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

WLAN : Oskyddad och okontrollerad datakommunikation

Horndahl, Charles, Maric, Kristian January 2005 (has links)
<p>This master’s thesis investigates the technology and security awareness associated with wireless networks (WLAN). It has been stated by the media and theories that many wireless networks are unprotected. This has sparked an interest to investigate the phenomenon in the Jonkoping region. The study is based on the following research questions:</p><p>- What security weaknesses are present with the WLAN-technology and how can these be avoided?</p><p>- How does the wireless infrastructure in the Jonkoping region look like?</p><p>- Why do companies implement the WLAN-technology?</p><p>- Are the companies aware of the risks involved with WLAN?</p><p>We conducted this study in three steps; the first step was to hack a wireless network in a controlled environment in order to investigate the weaknesses of the commonly used security measures. The second step of the study was to scan the wireless networks in Jonkoping, Gnosjo and Nassjo in order to create a picture of the wireless infrastructure of the region. The third step of the study was to contact companies that we found in the second step for interviews to investigate their awareness of the technology and its weaknesses.</p><p>We found that WLANs and their security measures have weaknesses. The commonly used WEP encryption can quite easily be broken and can lure users into a false sense of security. The study shows that companies are aware of this weakness, but use the encryption be-cause it offers a good level of usability and security. It is a compromise between usability and security. Usability is one of the major factors for companies when implementing wireless networks, companies strive for mobility, easy access and ease of use, which the WLAN technology offers. This has lead to an extended wireless infrastructure in cities within the region where one, with ease, can find wireless networks outside buildings. We have noticed an increase in the security awareness as our empirical findings differ from earlier research conducted in other cities. When these studies are compared you can see a trend where the number of unprotected networks decreases. Our contribution to increased wireless security is a checklist of possible security measures to minimize the security threats.</p> / <p>Denna magisteruppsats undersöker tekniken och säkerhetsmedvetandet gällande trådlösa nätverk (WLAN). Då det tidigare uppmärksammats i media och teori att många trådlösa nätverk står oskyddade har detta skapat intresse att undersöka fenomenet i Jönköpingsregionen. Studien baseras på följande frågeställningar:</p><p>- Vilka säkerhetsluckor finns i WLAN och hur kan dessa undvikas?</p><p>- Hur ser WLAN-infrastrukturen ut i Jönköpingsregionen?</p><p>- Varför implementerar företag WLAN-tekniken?</p><p>- Är företag medvetna om riskerna med trådlösa nätverk?</p><p>För att skapa en helhetsbild har vi genomfört studien i tre steg varav vi, i det första steget, genomfört dataintrång i en kontrollerad miljö för att undersöka svagheterna med säkerhetsfunktionerna som används i trådlösa nätverk. I det andra steget undersökte vi med hjälp av bärbar dator trådlösa nätverk i Jönköping, Gnosjö och Nässjö. Detta för att skapa oss en uppfattning om hur WLAN-infrastrukturen ser ut i dagsläget. Steg tre innebar intervjuer med företag som vi funnit i samband med steg två rörande deras medvetenhet om tekniken och dess brister.</p><p>Teorin och vår empiri gav oss underlag att dra slutsatser utifrån våra frågeställningar. Vi fann att WLAN och dess säkerhetsfunktioner har vissa sårbarheter. Den mest förekommande krypteringstekniken, WEP, kan dekrypteras tämligen enkelt och kan vagga in användarna i en falsk säkerhet. Studien visar att företagen är medvetna om detta, men att det handlar om en medveten kompromiss mellan användarvänlighet och säkerhet. Användarvänligheten står till grund för varför företagen väljer att implementera den trådlösa tekniken. Företag eftersträvar mobilitet, smidighet och enkel access, vilket den trådlösa tekniken erbjuder. Detta har lett till en utökad trådlös infrastruktur i städer runtom i regionen där man med lätthet kan hitta trådlösa nätverk utanför byggnader. Vi har noterat ett ökat säkerhetsmedvetande då våra empiriska resultat skiljer sig något från tidigare undersökningar i andra städer. När dessa ställs mot varandra anar man en trend där antalet oskyddade trådlösa nätverk minskar. Vårt bidrag till ökad trådlös säkerhet är en checklista med möjliga åtgärder för att minimera säkerhetsriskerna.</p>
72

Bristfällig säkerhet inom trådlösa routrar med fokus på WPS

Juhlin, Tobias, Wangberg, Dan January 2014 (has links)
I denna rapport undersöks WPS-funktionen då det uppmärksammats säkerhetshåli den. Intervjuer, tester och observationer har gjorts för att undersöka problemenmed WPS. De tester och intervjuver som gjorts indikerar att säkerhetsbristen i WPS-funktionen har säkrats upp med extra funktioner. / In this report the WPS-function is evaluated due to the vulnerabilty of the protocol.Interviews, tests and observations have been conducted to evaluate the problems withWPS. The tests and interviews conducted indicates that the vulnerability of the WPS-function has been secured with extra functions.
73

Bristfällig säkerhet inom trådlösa routrar med fokus på WPS

Juhlin, Tobias, Wangberg, Dan January 2014 (has links)
I denna rapport undersöks WPS-funktionen då det uppmärksammats säkerhetshål i den. Intervjuer, tester och observationer har gjorts för att undersöka problemen med WPS. De tester och intervjuver som gjorts indikerar att säkerhetsbristen i WPS-funktionen har säkrats upp med extra funktioner. / In this report the WPS-function is evaluated due to the vulnerabilty of the protocol. Interviews, tests and observations have been conducted to evaluate the problems with WPS. The tests and interviews conducted indicates that the vulnerability of the WPS-function has been secured with extra functions.
74

Ramverk för Soft Front Panels och nyttjandet av wifi i känsliga miljöer / Framework for Soft Front Panels and the Utilization of Wifi in Sensitive Environments

Johansson, Tobias, Arvidsson, Martin January 2018 (has links)
Denna rapport täcker framtagandet av en prototyp för ett ramverk av soft front panels för testutrustning hos Saab Support and Services [1]. Prototypen ska användas av Saab i en utvärdering rörande en möjlig implementation och nyttan av ett sådant ramverk i Saabs befintliga system. Under framtagandet av prototypen har även en utredning rörande möjligheterna och problemen med att använda WiFi i känsliga miljöer utförts. Denna utredning är kopplad till prototypen i den mening att det finns ambition från Saab att använda liknande system trådlöst. Prototypen är även framtagen för att stödja WiFi som medel för kommunikation med den utrustning den är kopplad mot. Efter en utvärdering av olika ramverk valdes WPF som ramverk för framtagandet av prototypen. Programmeringen skedde i programmeringsspråket C# och XAML. Prototypen kopplades initialt upp mot simulerade instrument, för att ge ökad flexibilitet under utvecklingen. Den färdiga prototypen testades med faktiskt hårdvara tillsammans med simulerade PXI-moduler och uppvisade ett gott resultat. Fördjupningen angående användningen av WiFi i känsliga miljöer resulterade i ett antal förslag på åtgärder för att motverka störningar och signalläckage, så som användningen av WiFi-protokoll med höga frekvensband och ”defensive jamming”. / This report covers the creation of a prototype for a framework of soft front panels for test equipment at Saab Support and Services [1]. The prototype will be used by Saab in an evaluation regarding the possible implementation and benefits of such a framework in Saabs current system. During the creation of the prototype there has been an in-depth look at the possibilities and problems regarding the use of WiFi in sensitive environments. This in-depth look is tied to the prototype in such a way that there is an ambition at Saab of utilizing similar systems wirelessly. The prototype has been created in such a way that it supports WiFi as means of communication with the equipment it is connected to. After an evaluation of different frameworks WPF was chosen for the development of the prototype. The programming was done in the programming language C# and XAML. The prototype was initially connected to a set of simulated instruments, for increased flexibility during the development. The completed prototype was tested with actual hardware together with simulated PXI-modules and the results where satisfactory. The in-depth look regarding the use of WiFi in sensitive environments resulted in a number of suggestions for actions to counter interference and leakage of signals, such as the use of WiFi-protocols using a high frequency band and ”defensive jamming”.
75

Trådlöst campus i Växjö

Dich, Silas January 2005 (has links)
Internet Service Providers (ISP) har på senare år etablerat ett ökat antal Wi-Fi Hotspots på publika platser för att erbjuda Internettjänster så som e-post, Web och andra Internet-baserade program, till resande användare. Exempel på dessa platser är flygplatser, skolor, parker och städer. Växjö universitet har valt att bygga etttrådlöst nätverk på campus som man ska påbörja under sommaren 2005. Uppsatsen tar upp detta som fallstudie för diskussion av ämnet. / Lately Internet Service Providers (ISP) have established an increased amount of Wi-Fi Hotspots at public places to offer Internet based services like e-mail, web surfing etc to roaming users. Example of places like this are airports, schools, parks and cities. Växjö University has decided to implement a wireless network covering the university campus. This project is planned to start during summer of 2005. This project is the unicase for discussion in this bachelor thesis
76

EzMole: A new prototype for securing public Wi-Fi connections

Karlsson, Rickard January 2017 (has links)
When public Wi-Fi networks are being used, it can be hard to know who else that is using the same network or is monitoring the traffic that is traveling across the network. If the network is public and unencrypted anyone can monitor the traffic and to use these networks for work can be very risky. This is a big problem that needs a solution because the information that travels across the public network might have organizational secrets or sensitive personal information that shouldn’t be read by outsiders. One way to significantly increase the security while using these public networks is by configuring and setting up a VPN-tunnel, all traffic will then be sent encrypted. But nowadays many computers and mobile phones runs applications in the background that are actively asking for updates. It can for example be news apps, mail clients or instant messaging services like WhatsApp or Telegram. Since the apps is pushing for updates in the background there is a big risk that these programs are asking for updates and therefore transmit and receives information unencrypted over the public network before they have been able to set up their VPN-tunnel. People might be unaware about this problem and this research can be used to explain the problem and offer a solution to it and that is the reason why this research is important. This research tries to solve the problem and find answers to the research questions, “How to design and implement an affordable intermediate device that offers the user secure access to Internet on public Wi-Fi networks?" and “What are the design principles of that method?”. The proposed solution to solve this problem was to design and implement a new intermediate device, which was called EzMole, in between the public Wi-Fi and the users’ personal devices. The new device will operate and secure the users’ devices from potential malicious users on the public Wi-Fi while the VPN-tunnel is being established. It will also create a new encrypted wireless network that will be used to connect the personal devices to EzMole, for example mobile phone or laptop. The methodology that was used to design and develop the new EzMole-device was the Design Science Research Methodology. It includes six steps that was used during three phases of the project that worked in an iterative process with development, testing and evaluation until the device met the initial requirements of a successful device. There were tests for both functionality and security to make sure that it worked in the right way and that it didn’t have any known security weaknesses or flaws. This was very important since EzMole will be and represent an Internet-of-Things(IoT)-device and therefore the security had a big focus. After the tests, it was time to evaluate it against the initial requirements and the new device lived up to 9/12 requirements and was therefore classified as successful. The research contributes with a universal solution for the research problem and it gives answers to the research questions and in the meantime, reduces the gap in the literature. It also contributes with providing a new piece of hardware that will can help people to connect to the Internet in a more secure way when they are using public Wi-Fi networks.
77

WPS - WiFi Protected Setup : En studie om Wi-Fi Protected Setup som autentiseringsmetod

Lindell, Jonas, Lagerholm, Filip January 2019 (has links)
No description available.
78

Voz e vídeo sobre redes sem fio IEEE 802.11 / Voice and Video over IEEE 802.11 wireless networks.

Conceição, Arlindo Flavio da 15 May 2006 (has links)
Esta tese analisa aplicações de transmissão de voz e vídeo sobre redes Wi-Fi (IEEE 802.11). Os principais problemas observados foram a maior incidência de tráfegos em rajada e os problemas associados à execução de handoffs. Foram propostos algoritmos adaptativos para monitorar e contornar esses problemas. / This thesis examines applications for transmitting voice and video over Wi-Fi (IEEE 802.11). The main problems observed were the higher incidence of bursty traffic and disconnection during handoffs. Adaptive algorithms have been proposed to monitor and work around these problems.
79

Smartphone-based indoor positioning using Wi-Fi, inertial sensors and Bluetooth / Positionnement intérieur basé sur les smartphones à l'aide de Wi-Fi, des capteurs inertiels et Bluetooth

Ta, Viet-Cuong 15 December 2017 (has links)
Grâce à l’émergence dans la vie quotidienne des appareils de plus en plus populaires que sont les smartphones et les tablettes, la tâche de postionner l'utilisateur par le biais de son téléphone est une problématique fortement étudiée dans les domaines non seulement de la recherche mais également des communautés industrielles. Parmi ces technologies, les approches GPS sont devenues une norme et ont beaucoup de succès pour une localisation en environnement extérieur. Par contre, le Wi-Fi, les capteurs inertiels et le Bluetooth sont plutôt préférés pour les tâches de positionnement dans un environnement intérieur.Pour ce qui concerne le positionnement des smartphones, les approches basées sur les « empreintes digitales » (fingerprint) Wi-Fi sont bien établies. D'une manière générale, ces approches tentent d'apprendre la fonction de correspondance (cartographie) des caractéristiques du signal Wi-Fi par rapport à la position de l’appareil dans le monde réel. Elles nécessitent généralement une grande quantité de données pour obtenir une bonne cartographie. Lorsque ces données d'entraînement disponibles sont limitées, l'approche basée sur les empreintes digitales montre alors des taux d’erreurs élevés et devient moins stable. Dans nos travaux, nous explorons d’autres approches, différentes, pour faire face à cette problématique du manque de données d'entraînement. Toutes ces méthodes sont testées sur un ensemble de données public qui est utilisé lors d’une compétition internationale à la Conférence IPIN 2016.En plus du système de positionnement basé sur la technologie Wi-Fi, les capteurs inertiels du smartphone sont également utiles pour la tâche de suivi. Les trois types de capteurs, qui sont les accéléromètres, le gyroscope et la boussole magnétique, peuvent être utilisés pour suivre l'étape et la direction de l'utilisateur (méthode SHS). Le nombre d'étapes et la distance de déplacement de l'utilisateur sont calculés en utilisant les données de l'accéléromètre. La position de l'utilisateur est calculée par trois types de données avec trois méthodes comprenant la matrice de rotation, le filtre complémentaire et le filtre de Madgwick. Il est raisonnable de combiner les sorties SHS avec les sorties de Wi-Fi, car les deux technologies sont présentes dans les smartphones et se complètent. Deux approches combinées sont testées. La première approche consiste à utiliser directement les sorties Wi-Fi comme points de pivot pour la fixation de la partie de suivi SHS. Dans la deuxième approche, nous comptons sur le signal Wi-Fi pour construire un modèle d'observation, qui est ensuite intégré à l'étape d'approximation du filtre à particules. Ces combinaisons montrent une amélioration significative par rapport au suivi SHS ou au suivi Wi-Fi uniquement.Dans un contexte multiutilisateur, la technologie Bluetooth du smartphone pourrait fournir une distance approximative entre les utilisateurs. La distance relative est calculée à partir du processus de numérisation du périphérique Bluetooth. Elle est ensuite utilisée pour améliorer la sortie des modèles de positionnement Wi-Fi. Nous étudions deux méthodes. La première vise à créer une fonction d'erreur qui permet de modéliser le bruit dans la sortie Wi-Fi et la distance approximative produite par le Bluetooth pour chaque intervalle de temps spécifié. La seconde méthode considère par contre cette relation temporelle et la contrainte de mouvement lorsque l'utilisateur se déplace. Le modèle d'observation du filtre à particules est une combinaison entre les données Wi-Fi et les données Bluetooth. Les deux approches sont testées en fonction de données réelles, qui incluent jusqu'à quatre utilisateurs différents qui se déplacent dans un bureau. Alors que la première approche n'est applicable que dans certains scénarios spécifiques, la deuxième approche montre une amélioration significative par rapport aux résultats de position basés uniquement sur le modèle d'empreintes digitales Wi-Fi. / With the popularity of smartphones and tablets in daily life, the task of finding user’s position through their phone gains much attention from both the research and industry communities. Technologies integrated in smartphones such as GPS, Wi-Fi, Bluetooth and camera are all capable for building a positioning system. Among those technologies, GPS has approaches have become a standard and achieved much success for the outdoor environment. Meanwhile, Wi-Fi, inertial sensors and Bluetooth are more preferred for positioning task in indoor environment.For smartphone positioning, Wi-Fi fingerprinting based approaches are well established within the field. Generally speaking, the approaches attempt to learn the mapping function from Wi-Fi signal characteristics to the real world position. They usually require a good amount of data for finding a good mapping. When the available training data is limited, the fingerprinting-based approach has high errors and becomes less stable. In our works, we want to explore different approaches of Wi-Fi fingerprinting methods for dealing with a lacking in training data. Based on the performance of the individual approaches, several ensemble strategies are proposed to improve the overall positioning performance. All the proposed methods are tested against a published dataset, which is used as the competition data of the IPIN 2016 Conference with offsite track (track 3).Besides the positioning system based on Wi-Fi technology, the smartphone’s inertial sensors are also useful for the tracking task. The three types of sensors, which are accelerate, gyroscope and magnetic, can be employed to create a Step-And-Heading (SHS) system. Several methods are tested in our approaches. The number of steps and user’s moving distance are calculated from the accelerometer data. The user’s heading is calculated from the three types of data with three methods, including rotation matrix, Complimentary Filter and Madgwick Filter. It is reasonable to combine SHS outputs with the outputs from Wi-Fi due to both technologies are present in the smartphone. Two combination approaches are tested. The first approach is to use directly the Wi-Fi outputs as pivot points for fixing the SHS tracking part. In the second approach, we rely on the Wi-Fi signal to build an observation model, which is then integrated into the particle filter approximation step. The combining paths have a significant improvement from the SHS tracking only and the Wi-Fi only. Although, SHS tracking with Wi-Fi fingerprinting improvement achieves promising results, it has a number of limitations such as requiring additional sensors calibration efforts and restriction on smartphone handling positions.In the context of multiple users, Bluetooth technology on the smartphone could provide the approximated distance between users. The relative distance is calculated from the Bluetooth inquiry process. It is then used to improve the output from Wi-Fi positioning models. We study two different combination methods. The first method aims to build an error function which is possible to model the noise in the Wi-Fi output and Bluetooth approximated distance for each specific time interval. It ignores the temporal relationship between successive Wi-Fi outputs. Position adjustments are then computed by minimizing the error function. The second method considers the temporal relationship and the movement constraint when the user moves around the area. The tracking step are carried out by using particle filter. The observation model of the particle filter are a combination between the Wi-Fi data and Bluetooth data. Both approaches are tested against real data, which include up to four different users moving in an office environment. While the first approach is only applicable in some specific scenarios, the second approach has a significant improvement from the position output based on Wi-Fi fingerprinting model only.
80

DISpatCH: Uma abordagem SDWN para o gerenciamento do processo de handoff nas redes Wi-Fi

Quaresma Filho, José Gomes 31 August 2016 (has links)
Submitted by Fernando Souza (fernandoafsou@gmail.com) on 2017-08-16T11:08:57Z No. of bitstreams: 1 arquivototal.pdf: 14592184 bytes, checksum: e1af48f8997b6af87f0fc91dd6d4a697 (MD5) / Made available in DSpace on 2017-08-16T11:08:57Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 14592184 bytes, checksum: e1af48f8997b6af87f0fc91dd6d4a697 (MD5) Previous issue date: 2016-08-31 / One of the most important aspects concerning the implementation of a Wireless Local Area Network (WLAN) is that in an area covered by several Access Points (APs), there must exist mechanisms to keep the user connected at any time, regardless of his/her physical location in the network and, primarily, ensure that the applications do not suffer from loss of connectivity. In this context, handoff performance, which consists of changing the AP as the station moves within the same area, is a preponderant factor when it comes to applications that are delay-sensitive. The process is usually started by the stations that once disconnected from an AP, start scanning the existing channels searching for other available APs in a smooth fashion, but in the order of seconds, which makes it difficult to use real-time applications. The challenge is to create a more efficient mechanism to manage this process, providing the required Quality of Service (QoS) for the applications. This work presents the use of mechanisms to improve the performance of the handoff process by employing an approach based on the a Software DefinedWireless Network (SDWN), which was implemented to validate the proposal. The tests performed showed a decrease in the time spent in the handoff, contributing to guarantee the QoS of the applications. / Um dos aspectos mais importantes na implantação de uma rede local sem fio Wireless Local Area Network (WLAN) é que em uma área coberta por vários Access Points (APs), devem existir mecanismos que sejam suficientes para que o usuário possa se manter conectado a qualquer hora independentemente de sua localização física dentro da rede e, principalmente, garantir que as aplicações não sofram com falhas ou perdas de conexão. Neste contexto, o desempenho do handoff, que consiste na troca de AP à medida que uma estação se move dentro de uma mesma área, é fator determinante para o uso de aplicações sensíveis ao atraso. Normalmente o processo é iniciado pelas estações, que ao se desconectarem de um AP iniciam uma varredura nos canais existentes buscando outros APs disponíveis de forma suave, porém na ordem de segundos, o que dificulta o uso de aplicações em tempo real. O desafio é criar um mecanismo mais eficiente para gerenciar este processo provendo a Qualidade de Serviço (QoS) necessária para as aplicações. Este trabalho apresenta uma solução denominada Detection and dIScovery Control in Handoff (DISpatCH) que utiliza mecanismos para melhorar o desempenho do processo de handoff utilizando uma abordagem baseada na arquitetura Software Defined Wireless Network (SDWN) os quais foram implementados para validar a proposta. Testes realizados demonstraram uma diminuição no tempo gasto no handoff contribuindo para garantir o QoS das aplicações.

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