In this thesis, we considered different approaches for quantifying information hiding in communication protocols.

<p>Syftet är att ta reda på vad som menas med anonymitet i dagens kameraövervakade stad. Dentraditionella uppfattningen är att stadens karaktär är anonymitet och syftet är att ta reda på huranonymiteten ser ut idag när stadsmedborgarna är kameraövervakade. Studien är en begreppsutredning av anonymitet, och dess relaterade begrepp trygghet.Huvudsakligen används Simmels teori om storstaden och Foucaults teori om övervakning,men också teoretikerna Jane Jacobs och Mike Davis och deras syn på trygghet i staden så välsom en del andra källor. Jag kopplar Simmel och Foucault till anonymitetet och trygghet,tillämpat på dagens stad. Slutsatserna är att dagens stadsmänniska är både anonym och inte, beroende på hur man serdet. De som syns i kamerans blick är de som begår brott, medan de andra fortfarande äranonyma. Gällande tryggheten kan den uppnås genom ett levande folkliv. Det handlar om attmänniskor ska våga sig ut i staden och inte stänga in sig på grund av sin rädsla. Blir stadenöde så försvinner dess traditionella karaktär, det vill säga möjligheten till möten mellan olikamänniskor. Uppsatsen är uppdelad i fyra kapitel, varav det första är inledande, sedan följer enpresentation av de centrala teorierna. Det tredje kapitlet är ägnat åt att utveckla trygghetensoch tillitens begreppsmässiga mening i relation till samtida kameraövervakade städer. Detslutliga kapitlet drar slutsatsen att det inte finns någon inneboende spänning mellankameraövervakning och trygghet, men samtidigt finns det ingen garanti att en ökning avkameraövervakning kommer att resultera i ökad offentlig trygghet.</p>

<p>Many security services today only provides one security configuration at run-time, and cannot then utilize the trade-off between performance and security. In order to make use of this trade-off, tunable security services providing several security configurations that can be selected at run-time are needed. To be able to make intelligent choices on which security configuration to use for different situations we need to know how good they are, i.e., we need to order the different security configurations with respect to each security attribute using measures for both security and performance.</p><p>However, a key issue with computer security is that it is due to its complex nature hard to measure.</p><p>As the title of this thesis indicates, it discusses both security measures and tunable security services. Thus, it can be seen to consist of two parts. In the first part, discussing security measures for tunable security services, an investigation on the security implications of selective encryption by using guesswork as a security measure is made. Built on this an investigation of the relationship between guesswork and entropy. The result shows that guesswork,</p><p>after a minor redefinition, is equal to the sum of the entropy and the relative entropy.</p><p>The second part contributes to the area of tunable security services, e.g., services that provides several security configurations at run-time. In particular, we present the mobile Crowds (mCrowds) system,</p><p>an anonymity technology for the mobile Internet developed at Karlstad University, and a tunable encryption service, that is based on a selective encryption paradigm and designed as a middleware. Finally, an investigation of the tunable features provided by Mix-Nets and Crowds are done, using a conceptual model for tunable security services.</p>

<p>A person who is communication about (the data subject) has to keep track of all of his revealed data in order to protect his right of informational self-determination. This is important when data is going to be processed in an automatic manner and, in particular, in case of automatic inquiries. A data subject should, therefore, be enabled to recognize useful decisions with respect to data disclosure, only by using data which is available to him.</p><p>For the scope of this thesis, we assume that a data subject is able to protect his communication contents and the corresponding communication context against a third party by using end-to-end encryption and Mix cascades. The objective is to develop a model for analyzing the linkability of communication contents by using Formal Concept Analysis. In contrast to previous work, only the knowledge of a data subject is used for this analysis instead of a global view on the entire communication contents and context.</p><p>As a first step, the relation between disclosed data is explored. It is shown how data can be grouped by types and data implications can be represented. As a second step, behavior, i. e. actions and reactions, of the data subject and his communication partners is included in this analysis in order to find critical data sets which can be used to identify the data subject.</p><p>Typical examples are used to verify this analysis, followed by a conclusion about pros and cons of this method for anonymity and linkability measurement. Results can be used, later on, in order to develop a similarity measure for human-computer interfaces.</p>

During the period between 1640 and 1700, over forty works were produced by authors identifying themselves as “T. S.” In the field of early modern literary studies, one T. S. has been particularly important to scholars because of this author’s imitative version of John Bunyan’s popular allegory titled The Second Part of the Pilgrim’s Progress (1682). This work by T. S., who has become known as Thomas Sherman, achieves minor success and prompts Bunyan to write his own authentic sequel. My research has uncovered an attribution history that identifies four additional texts—Divine Breathings (circa 1671); Youth’s Tragedy (1671); Youth’s Comedy (1680); Divine Breathings, the Second Part (1680)—and credits all of them to a Thomas Sherman. Of the five works attributed to this author, the most impressive printing history belongs to the earliest offering, Divine Breathings, or a Pious Soul Thirsting after Christ in a Hundred Pathetical Meditations, which appears in over 60 printings from 1671 to 1883 in England, Scotland, and North America. My research scrutinizes this attribution history and raises questions about identifying this T. S. as Thomas Sherman. Based on internal and external evidence, I argue that T. S. is not the author of Divine Breathings but establishes his authorial identity as an imitative writer who actively participates in the genre of Protestant meditational literature by providing sequels (i.e., Divine Breathings …the Second Part and Second Part of the Pilgrim’s Progress).

Syftet är att ta reda på vad som menas med anonymitet i dagens kameraövervakade stad. Dentraditionella uppfattningen är att stadens karaktär är anonymitet och syftet är att ta reda på huranonymiteten ser ut idag när stadsmedborgarna är kameraövervakade. Studien är en begreppsutredning av anonymitet, och dess relaterade begrepp trygghet.Huvudsakligen används Simmels teori om storstaden och Foucaults teori om övervakning,men också teoretikerna Jane Jacobs och Mike Davis och deras syn på trygghet i staden så välsom en del andra källor. Jag kopplar Simmel och Foucault till anonymitetet och trygghet,tillämpat på dagens stad. Slutsatserna är att dagens stadsmänniska är både anonym och inte, beroende på hur man serdet. De som syns i kamerans blick är de som begår brott, medan de andra fortfarande äranonyma. Gällande tryggheten kan den uppnås genom ett levande folkliv. Det handlar om attmänniskor ska våga sig ut i staden och inte stänga in sig på grund av sin rädsla. Blir stadenöde så försvinner dess traditionella karaktär, det vill säga möjligheten till möten mellan olikamänniskor. Uppsatsen är uppdelad i fyra kapitel, varav det första är inledande, sedan följer enpresentation av de centrala teorierna. Det tredje kapitlet är ägnat åt att utveckla trygghetensoch tillitens begreppsmässiga mening i relation till samtida kameraövervakade städer. Detslutliga kapitlet drar slutsatsen att det inte finns någon inneboende spänning mellankameraövervakning och trygghet, men samtidigt finns det ingen garanti att en ökning avkameraövervakning kommer att resultera i ökad offentlig trygghet.

Denna studie jämför hur kommentarer till nätartiklar på Aftonbladet.se har förändrats från 2010 till 2011 vad gäller innehåll, språk och ton. Mellan dessa år har systemet för kommentering ändrats på Aftonbladet.se, från att det 2010 krävdes registrering och att kommentatorn fick välja ett valfritt alias, till att kommentering sker via ett redan registrerat Facebook-konto med kommentatorns riktiga namn. Studiens syfte är att ta reda på hur diskussionerna och språket i kommentarsfälten påverkas när kommentatorn inte längre får vara anonym. Med kvantitativ innehållsanalys undersöks två artiklars kommentarer per dag under en vecka, 14 till 20 oktober 2010 och 2011, 14 artiklar från varje år. Urvalet av artiklar utgår från vilka artiklar som topplacerats i Aftonbladets pappersupplaga samma dag. Totalt har 1452 kommentarer undersökts med 28 variabler. Variablerna berör bland annat huruvida kommentaren är kritisk, om den svarar på en annan kommentar och om den innehåller stavfel eller andra språkliga misstag. Efter att kodningen genomförts gjordes ett reliabilitetstest där 30 redan undersökta kommentarer analyserades en gång till för att stärka resultatets validitet. Huvudresultatet visar att det 2011 pågår en mer aktiv diskussion mellan de som kommenterar och att kvinnorna har tagit mer plats i kommentarsfälten än tidigare. Detta kan ha sin förklaring i att det är mer lättillgängligt att kommentera via ett Facebook-konto förutsatt att man redan har ett registrerat konto. Språkbruket är i princip det samma båda åren, men kommentarerna har blivit längre och mer sakliga. / This study compares reader comments on articles displayed on Aftonbladet.se, in terms of content and language. Between these years the system for commenting on Aftonbladet.se has changed from a registration, when the user could choose their own alias, to commenting using their already existing Facebook-account with the user’s real name. This study answers the question how and if the reader comments change when the option of being anonymous disappears. This study analyses readers’ comments of two articles every day during two weeks, October 14th to October 20th 2010 and 2011, with a total of 14 articles each year. The selection of articles was based on the articles placement in the printed newspaper Aftonbladet the same day. 1452 comments have been studied through 28 variables. Some of the most important variables were; whether the comment is critical, whether the comment answers another comment and if it contains spelling mistakes. In order to strengthen the validity of the study a test of the reliability was made and 30 comments were re-analysed one more time. The main results of the study indicates that the debate was more active between the users in 2011 than in 2010 and that women to a higher extent started to take place in the commenting area. These results are probably an effect of using the Facebook account for commenting, which is accessible and easy to use.

Despite recent interest in the role of trust in Information Systems, the potential of IS to foster trust in business relationships remains largely untapped. In order to better realize this potential, this dissertation examines three areas of IS trust research for which research is particularly limited: (1) the IT artifact as a target of trust, (2) IS-based source credibility as an antecedent of trust, and (3) the effect of anonymity on trust in online environments. The objective of this dissertation is to examine the effects of IS on trust in each of these areas. To do so, a multi-paper dissertation format is adopted in which each area examined constitutes a distinct, though complimentary, study. Together, these studies further research on how IS can enhance trust in business relationships.

A digital signature scheme is the process of signing an electronic message that can be transmitted over a computer network. Digital signatures provide message authentication that can be proved to a third party. With the rise of electronic communications over the Internet, digital signatures are becoming increasingly important, especially for the exchange of messages of legal significance. In 1988, Goldwasser, Micali and Rivest (GMR) [31] defined a signature scheme as a collection of algorithms: key generation, signature generation and signature verification. They defined a signature scheme as secure if it was existentially unforgeable against a chosen-message attack. These general definitions suited most signatures at the time, however, over the last decade digital signatures have emerged for which the GMR definitions are unsuitable. These signature schemes, together with their applications and security and efficiency considerations, will be explored in this thesis. These signature scheme variations have been classified by the additional services they provide to ordinary signature schemes, namely increased efficiency, increased security, anonymity, and enhanced signing and verifying capabilities.

A digital signature scheme is the process of signing an electronic message that can be transmitted over a computer network. Digital signatures provide message authentication that can be proved to a third party. With the rise of electronic communications over the Internet, digital signatures are becoming increasingly important, especially for the exchange of messages of legal significance. In 1988, Goldwasser, Micali and Rivest (GMR) [31] defined a signature scheme as a collection of algorithms: key generation, signature generation and signature verification. They defined a signature scheme as secure if it was existentially unforgeable against a chosen-message attack. These general definitions suited most signatures at the time, however, over the last decade digital signatures have emerged for which the GMR definitions are unsuitable. These signature schemes, together with their applications and security and efficiency considerations, will be explored in this thesis. These signature scheme variations have been classified by the additional services they provide to ordinary signature schemes, namely increased efficiency, increased security, anonymity, and enhanced signing and verifying capabilities.