<p>In the age of a networking revolution, when the Internet has changed not only the way we see computing, but also the whole society, we constantly face new challenges in the area of user verification. It is often the case that the login-id password pair does not provide a sufficient level of security. Other, more sophisticated techniques are used: one-time passwords, smart cards or biometric identity verification. The biometric approach is considered to be one of the most secure ways of authentication. </p><p>On the other hand, many biometric methods require additional hardware in order to sample the corresponding biometric feature, which increases the costs and the complexity of implementation. There is however one biometric technique which does not demand any additional hardware – user identification based on keyboard statistics. This thesis is focused on this way of authentication. </p><p>The keyboard statistics approach is based on the user’s unique typing rhythm. Not only what the user types, but also how she/he types is important. This report describes the statistical analysis of typing samples which were collected from 20 volunteers, as well as the implementation and testing of the identity verification system, which uses the characteristics examined in the experimental stage.</p>

<p>This thesis is about the design and evaluation of a graphical display that aims at showing the behavior of a complex automated system in action. A problem with complex automation is that it sometimes surprises the user by performing actions that were not expected. The reason of this is poor communication of system activities. In order to study how to design for anticipative automation communication a prototype around automatic vehicle driving on highways was designed and evaluated. The design work focused on designing a display that contained anticipation as a use quality. This resulted in a display design that aimed at representing the working scene in such a way that the user would be able to recognize and compare the system view with the real situation. In order to accomplish this, three layers of information were merged together in the display, these layers were; the automaton’s image of how the world is seen, the way that image is perceived and interpreted in terms of system action necessity and out of that the actions that the system plans to perform in the near future. The evaluation of the design prototype showed that it was possible to anticipate system actions but that the information detail level was insufficient for the evaluators to completely trust system decisions. The evaluation also showed that trust can be created by letting the automaton represent the perception of the situation in such a way that the user is able to compare it to personal experience from performing the task manually. Anticipation can be created through showing what future the automaton is expecting and what actions that needs to be performed in order to reach or maintain the general system task or goal.</p>

<p>Zero knowledge protocols is a lesser known type of protocol that can be used for identification. These protocols are especially designed not to reveal any information during an identification process that can be misused later on, neither by the one who should be convinced of the identity of the user, nor by anyone else that is eavesdropping. Many of these protocols are also especially designed for implementation in smart cards. The more common type of card with a magnetic stripe has during the last few years become more susceptible to attacks since they are easily copied. Smart cards combined with a secure identification protocol has been predicted to be the solution to this problem. Zero knowledge protocols are one of several types of protocols that can be used for this purpose. </p><p>In this thesis a number of zero knowledge protocols are examined that have been presented since the introduction of the concept in the 1980's. In addition to the protocol descriptions information is also given about how to choose parameter values, and what progress and discoveries have been made concerning the security of the protocols. Some assumptions that are easy to overlook in an implementation are also highlighted, and an evaluation of the protocol performances is made. </p><p>The conclusion is that zero knowledge protocols are both efficient and adaptable, while they at the same time provide high security. Because of this it may not be necessary to compromise between these properties even for simpler types of smart cards.</p>

<p>Finnegan Lab System is a graphical computer program for learning how secret sharing works. With its focus on the algorithms and the data streams, the user does not have to consider machine-specific low-level details. It is highly modularised and is not restricted to secret sharing, but can easily be extended with new functions, such as building blocks for Feistel networks or signal processing. </p><p>This thesis describes what secret sharing is, the development of a new lab system designed for secret sharing and how it can be used.</p>

<p>This work contains a brief study about Forensic Computing problems done from a Computer Security perspective. </p><p>Based on the description and investigation methods of Forensic Computing, a list of common difficulties that forensic examiners have to deal with has been created. After making an analysis about each difficulty in the Forensic Computing field, it can be said that the main reasons are related to the legal restrictions and an incorrect security management. </p><p>Using a Computer Security perspective for analysing why the incorrect security management generates problems in the forensic computing field, we have made a risk analysis of a possible distribution for a correct security management. Later, based on own results, a list on priorities in prevention methods in t he Forensic Computing field has been created. </p><p>Finally it can be said that the difficulties in the Forensic Computing field could be avoided by creating awareness among users about the importance of taking prevention methods for protecting data and consequently for decreasing the number of e-crimes.</p>

<p>Background: The network-centric defense requires a method for securing vast dynamic distributed information systems. Currently, there are no efficient methods for establishing the level of IT security in vast dynamic distributed information systems. </p><p>Purpose: The target of this thesis was to design a method, capable of determining the level of IT security of vast dynamic component-based distributed information systems. </p><p>Method: The work was carried out by first defining concepts of IT security and distributed information systems and by reviewing basic measurement and modeling theory. Thereafter, previous evaluation methods aimed at determining the level of IT security of distributed information systems were reviewed. Last, by using the theoretic foundation and the ideas from reviewed efforts, a new evaluation method, aimed at determining the level of IT security of vast dynamic component-based distributed information systems, was developed. </p><p>Results: This thesis outlines a new method, CAESAR, capable of predicting the security level in parts of, or an entire, component-based distributed information system. The CAESAR method consists of a modeling technique and an evaluation algorithm. In addition, a Microsoft Windows compliant software, ROME, which allows the user to easily model and evaluate distributed systems using the CAESAR method, is made available.</p>

<p>Broadcast encryption is a fairly new area in cryptology. It was first addressed in 1992, and the research in this area has been large ever since. In short, broadcast encryption is used for efficient and secure broadcasting to an authorized group of users. This group can change dynamically, and in some cases only one-way communication between the sender and receivers is available. An example of this is digital TV transmissions via satellite, in which only the paying customers can decrypt and view the broadcast. </p><p>The purpose of this thesis is to develop a general Java framework for implementation and performance analysis of broadcast encryption algorithms. In addition to the actual framework a few of the most common broadcast encryption algorithms (Complete Subtree, Subset Difference, and the Logical Key Hierarchy scheme) have been implemented in the system. </p><p>This master’s thesis project was defined by and carried out at the Information Theory division at the Department of Electrical Engineering (ISY), Linköping Institute of Technology, during the first half of 2004.</p>

<p>Syftet med min undersökning är att utvärdera tillämpbarheten av metoden FA/SIMM. En utrednings- och analysansats som ska underlätta breda och välförankrade beslutsunderlag för förändringar inom olika verksamheter. Som underlag för min utvärdering har jag använt en fallstudie av grundutbildningen för informatikämnet inom ISM vid Institutionen för datavetenskap, Linköpings universitet. En fallstudie i vilken jag undersöker hur administrationen av kurser fungerar, administration i betydelsen planering, samordning och organisering av olika handlingar. I rapporten redovisar jag endast ett kort utdrag av resultatet från fallstudien. Däremot beskriver jag relativt utförligt hur det varit att arbeta praktiskt med FA/SIMM. Min upplevelse av arbetet har analyserats utifrån särskilda utvärderingskriterier som tagits fram under arbetets gång. </p><p>Resultatet av utvärderingen visar att tillämpbarheten totalt sett har stora brister för att FA/SIMM år 2003 ska kunna betraktas som praktisk att använda. Det gäller främst överskådligheten av metoden totalt. Det är inte genomskinligt vad FA/SIMM består av för delar och framför allt finns det inte någon lättillgänglig sammanställd beskrivning av alla ingående moment. Det saknas beskrivning av arbetssätt och analysstöd för vissa moment. Det finns inte heller några direkta praktiska hjälpmedel. Jag saknar också ett djupare beskrivande analysstöd som överensstämmer med metodförfattarnas perspektiv. Däremot finns det en flexibilitet att vid en verksamhetsdiagnos kunna välja vilka moment man vill använda beroende på syftet med diagnosen. </p><p>Trots ovanstående negativa kritik gick det att få fram en, i mitt tycke, relativt utförlig bild av verksamheten med en omfattande och bra översikt av bl a dess komplexitet.</p>

<p>Inom en yrkesgrupp finns det en samlad kunskap och ett yrkeskunnande. En stor del av denna kunskap är outtalad och svårdefinierad. När man överför arbetet till en datormiljö kan det vara av intresse att utforma programvaran på ett sådant sätt att användarna får möjlighet att utnyttja detta kunnande även här. </p><p>Genom att undersöka hur användare arbetar med ett verktyg, som uppenbarligen är designat för att hjälpa användare genom att låta dem utnyttja sin tidigare kunskap inom området, vill vi söka svar på hur detta kan fungera och vilka för- och nackdelar det medför. </p><p>Det verktyg vi använde för vår undersökning var Reason 2.5, ett musikprogram som erbjuder en simulering av en verklig studiomiljö. </p><p>Vi har under testerna sett tydliga tecken på att användarna utnyttjar sitt tysta kunnande i stor utsträckning då de arbetar med gränssnittet. Det stora användandet av metaforer och simuleringar gör att användarna känner igen sig, men det innebär också begränsningar i möjlig arbetsgång. Vi har även sett att man med denna typ av gränssnitt kan erhålla en låg inlärningströskel utan att inskränka på experters möjlighet att arbeta effektivt. Den låga inlärningströskeln är dock beroende av användarens tidigare erfarenhet. Ett simulerat gränssnitt bidrar till konserverandet av den traditionella bild av musikproduktion som är djupt rotad inom yrkesgruppen..</p>

<p>Hundreds of millions of people use their home computers every day for different purposes. Many of them are connected to the Internet. Most of them are unaware of the threats or do not know how to protect themselves. This unawareness is a major threat to global computer security. </p><p>This master thesis starts by explaining some security related terms that might be unknown to the reader. It then goes on by addressing security vulnerabilities and flaws in the most popular home computer operating systems. The most important threats to home computer security are reviewed in the following chapter. These threats include worms, email worms, spyware and trojan horses. After this chapter some possible solutions for improving home computer security are presented. Finally this master thesis contains a short user survey to find out what the problems are in the real world and what can be doneto improve the current situation.</p>