Electronic commerce and the internet provide greater opportunities for companies and individual person to be involved in commercial activities; the involved parties may not know or trust each other or may even be mutually suspicious of each other. The issue of fairness becomes more critical and must be well addressed. The aim of this thesis is to investigate security solutions with fairness for on-line transactions. A fair trading protocol with credit payment is proposed. The proof of equivalence of discrete logarithm to discrete loglogarithm is employed as the main tool to construct the protocol. The scheme provides a unique link between payment and gambling outcome so that the winner can be ensured to get the payment. Since an optimal fair exchange method is used in gambling message exchange, the proposed system guarantees that no one can successfully cheat during a gambling process. Our system requires an off-line Trusted Third Party (TTP). If cheating occurs, the TTP can resolve the problem and make the gambling process fair. An efficient and secure poker scheme is proposed. It is based on multiple encryption and decryption of individual cards. The protocol satisfies all major security requirements of a real mental poker. It gets rid of the Card Salesman and guarantees minimal effect due to collusion. The protocol is secure and more efficient compared with other known protocols. The strategies of players can be kept confidential with the introduction of a Dealer. The protocol is suitable to be implemented in an on-line gambling card game. The implementation of the fair on-line gambling protocol has been demonstrated and all utility classes for the implementation have been defined. / Master of Science (Hons)

Syftet har varit att på uppdrag av Periallo identifiera vad kunder tycker är viktigast ur ett säkerhetsperspektiv. Detta har skett genom att besvara frågorna vad som är viktigt för konsumenterna ur ett säkerhetsperspek-tiv när de handlar av små e-handelsföretag och vilka säkerhetslösningar samt betallösningar som är relevanta för små e-handelsföretag. Vi har även undersökt om det är värt för ett litet e-handelsföretag att investera i en certifiering. Arbetet har kartlagt betallösningar, säkerhetslösningar och certifieringar med hjälp av en kritisk litteraturstudie och med en enkät, det vill säga en kvantitativ metod. Resultatet av undersökningen har visat att de flesta kunderna känner sig trygga när de handlar på Internet. Den säkraste betallösningen anses vara faktura, medan de populäraste betalsätten är konto/kreditkort och direktbetalning. Utöver det har undersökningen också visat att det är viktigare för mindre och okända e-handelsföretag att tydligt visa vilka säkerhetslösningar de använder sig av gentemot de stora och kända företagen trots att de flesta av deltagarna inte var medvetna om vilka säkerhetslösningar som finns för att skydda företag och konsument. / The purpose of this study is, on behalf of Periallo, to identify what it is that customers consider to be of greatest importance from a security perspective. This has been conducted from the answers given by consumers when asked a question concerning what they deem to be important from a security perspective when they shop from small e-commerce companies. In addition, a consideration has also been given to the security and payment solutions that are relevant to small e-commerce companies. An examination has also been conducted as to whether it is worth a small e-commerce company investing in a certification. In this work, payment solutions, security solutions and certifications have been identified by means of a critical literature review and a questionnaire, which is a quantitative method. The results of the study have shown that the majority of customers feel that it is safe to shop online. The most secure payment solution is considered to be an invoice, while the most popular payment methods are debit/credit cards and direct payment. In addition, the study has also shown that it is more important for a small and unknown e-commerce company to properly reflect upon the security solutions that they use against the large and well-known companies, even though, the majority of the participants in this study, were not aware of the security solutions available to protect companies and consumers.

Récemment, le 3GPP (3rd Generation Partnership Project) a standardisé les systèmes LTE/LTE-A (Long Term Evolution/LTE-Advanced) qui ont été approuvés par l'UIT (Union Internationale des Télécommunications) comme des réseaux de télécommunications mobiles de 4éme génération. La sécurité est l'une des questions essentielles qui doivent être traitées avec soin pour protéger les informations de l'opérateur et des utilisateurs. Aussi, le 3GPP a normalisé plusieurs algorithmes et protocoles afin de sécuriser les communications entre les différentes entités du réseau. Cependant, l'augmentation du niveau de sécurité dans ces systèmes ne devrait pas leur imposer des contraintes lourdes telles qu’une grande complexité de calcul ou encore une forte consommation d'énergie. En effet, l'efficacité énergétique est devenue récemment un besoin critique pour les opérateurs afin de réduire l’empreinte écologique et les coûts opérationnels de ces systèmes. Les services de sécurité dans les réseaux mobiles tels que l'authentification, la confidentialité et l'intégrité des données sont le plus souvent effectués en utilisant des techniques cryptographiques. Toutefois, la plupart des solutions standardisées déjà adoptées par le 3GPP dépendent des algorithmes de chiffrement qui possèdent une grande complexité, induisant une consommation énergétique plus élevée dans les différentes entités communicantes du réseau. La confidentialité des données, qui se réfère principalement au fait de s'assurer que l'information n'est accessible qu'à ceux dont l'accès est autorisé, est réalisée au niveau de la sous-couche PDCP (Packet Data Convergence Protocol) de la pile protocolaire de LTE/LTE-A par l'un des trois algorithmes normalisés (EEA1, EEA2 et EEA3). Or, chacun des trois algorithmes exige une forte complexité de calcul car ils reposent sur la théorie de chiffrement de Shannon qui utilise les fonctions de confusion et de diffusion sur plusieurs itérations. Dans cette thèse, nous proposons un nouvel algorithme de confidentialité en utilisant le concept de substitution et de diffusion dans lequel le niveau de sécurité requis est atteint en un seul tour. Par conséquent, la complexité de calcul est considérablement réduite ce qui entraîne une réduction de la consommation d'énergie par les fonctions de chiffrement et de déchiffrement. De plus, la même approche est utilisée pour réduire la complexité des algorithmes 3GPP d'intégrité des données (EIA1, EIA2 et EIA3) dont le concept de chiffrement repose sur les mêmes fonctions complexes. Enfin, nous étudions dans cette thèse le problème d'authentification dans le contexte du paradigme D2D (Device to Device communications) introduit dans les systèmes 4G. Le concept D2D se réfère à la communication directe entre deux terminaux mobiles sans passer par le cœur du réseau. Il constitue un moyen prometteur pour améliorer les performances et réduire la consommation d'énergie dans les réseaux LTE/LTE-A. Toutefois, l'authentification et la dérivation de clé entre deux terminaux mobiles dans le contexte D2D n’ont pas fait l’objet d’études. Aussi, nous proposons un nouveau protocole léger d’authentification et de dérivation de clé permettant d’authentifier les terminaux D2D et de dériver les clés nécessaires à la fois pour le cryptage et pour la protection de l'intégrité des données. / Recently, the 3rd Group Project Partnership (3GPP) has developed Long Term Evolution/ Long Term Evolution-Advanced (LTE/LTE-A) systems which have been approved by the International Telecommunication Union (ITU) as 4th Generation (4G) mobile telecommunication networks. Security is one of critical issues which should be handled carefully to protect user's and mobile operator's information. Thus, the 3GPP has standardized algorithms and protocols in order to secure the communications between different entities of the mobile network. However, increasing the security level in such networks should not compel heavy constrains on these networks such as complexity and energy. Indeed, energy efficiency has become recently a critical need for mobile network operators for reduced carbon emissions and operational costs. The security services in mobile networks such as authentication, data confidentiality and data integrity are mostly performed using cryptographic techniques.However, most of the standardized solutions already adopted by the3GPP depend on encryption algorithms which possess high computational complexity which in turn contributes in consuming further energy at the different network communication parties.Data confidentiality which mainly refers to the protection of the user’s information privacy is achieved at the Packet Data Convergence Protocol (PDCP) sub-layer in the LTE/LTE-A protocol stack by one of the three standardized algorithms (EEA1, EEA2 and EEA3). However, each of the three algorithms requires high computational complexity since they rely on Shannon’s theory of encryption algorithms by applying confusion and diffusion for several rounds. In our thesis we propose a novel confidentiality algorithm using the concept of substitution and diffusion in which the required security level is attained in only one round. Consequently the computational complexity is considerably reduced which in return results in reducing the energy consumption during both encryption and decryption procedures. Similarly, the same approach is used to reduce the complexity of 3GPP data integrity algorithms (EIA1, EIA2 and EIA3) which the core cipher rely on the same complex functions. Finally, we investigate in this thesis the authentication issue in Device to Device paradigms proposal in 4G systems. Device to Device communications refer to direct communications between two mobile devices without passing through the core network. They constitute a promising mean to increase the performance and reduce energy consumptions in LTE/LTE-A networks. In such context, the authentication and key derivation between two mobile devices have not been well investigated. Thus, a novel lightweight authentication and key derivation protocol is proposed to authenticate two communicating devices during session establishments as well as deriving necessary keys for both data encryption and integrity protection.

Pagrindiniu įmonės tikslu laikomas įmonės vertės didinimas gali būti realizuojamas plečiant rinkos dalį, didinat parduodamų prekių ar paslaugų kiekį, taip pat didinant darbo organizavimo efektyvumą įmonėje. Vienas iš efektyvumo didinimo įmonėje sprendimų yra bevielio kompiuterių tinklo įmonėje diegimas. Naudojant bevielį kompiuterių tinklą pasiekiamas didesnis personalo mobilumas ir darbo efektyvumas, kai reikiamą informaciją darbuotojas gali gauti būdamas bet kurioje įmonės vietoje. Darbe atlikta bevielio tinklo diegimo metodų teorinė analizė, pasiūloma bevielio tinklo diegimo vertinimo metodika ir atliekamas metodikos taikymo tyrimas.Darbe pateikiama bevielio tinklo diegimo įmonėje metodika leidžia apskaičiuoti mobilumo naudą įmonei per papildomos vert���s sukūrimą ir kaštų sumažinimą, bei parinkti tinkamą bevielio tinklo architektūros ir saugumo sprendimus, atsižvelgiant į įmonės poreikius. Pristatomas modelis, leidžiantis įvertinti bevielio tinklo teikiamą naudą įmonėje. Bevielio kompiuterių tinklo architektūrinių sprendimų pritaikymo įmonei metodika formuluojama, remiantis atliktų eksperimentinių tyrimų rezultatais. / The main goal for a company is to increase its value which can be achieved by expanding the market share, increasing sales volume of its goods and services, improving labour productivity. One of the improvements aiming at achieving labour productivity is the implementation of wireless computer network. The use of wireless computer network gives a higher degree of mobility and efficiency for staff within the company, in particular when employee needs to access the information from any place in the territory of a company. This work contains from performed theoretic analysis of implementation methods of wireless network, the suggested methodology of Wireless Network evaluation and performed investigation of realised methodology of Wireless Network implementation in the company. The paper presents the methodology of wireless networks implementation in a company, evaluates the efficiency of wireless networks and suggests the possible architectural and security solutions for wireless networks implementation. Further more, the presented methodology enables to evaluate the benefits of mobility, in particular for added value creation and costs reduction, and allows choosing the appropriate architectural and security solutions of wireless computer network. The presented methodology is based on the results of experimental research.

In my diploma´s thesis I occupy with selected parts of the technological prepariation of building proceses of administrative and production hall in Holešov. There are detailed follow up the technological rules for ground work and foundation. Furthermore , the technological requirements for reinforced concrate assembled skeleton. My diploma´s thesis also includes the project of the construction site facilities, machinery, construction budget, the technology solution including CTP, the time and financial planning, noise studies, fire safety of the building, evaluation of roof cladding.