by Lau Chung-Hing. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1988. / Includes bibliographical references.

<p>This is a study on the development of a re-authentication prototype. Re- authentication serves as a receipt for e.g. system administrators that authorise them to carry out a critical operation in a system that already is protected by a security architecture. A critical operation is a kind of operation that can cause serious damage to a network node or a set of network nodes, if it is done without one giving it a second thought. The purpose is to prevent mistakes and secure the users’ audit trail. </p><p>The main task is to propose and implement a re-authentication prototype, that is to enable the incorporation of the re-authentication prototype to an already complete security architecture and yet preserve the security and performance level of the architecture. </p><p>This thesis deals with this problem by using digitally signed certificates to provide the necessary security issues. The certificates used are called re- authentication certificates and follows the X.509 attribute certificate standard. The re-authentication certificate is optimised so that it only holds authorisation information regarding one critical operation. An access control decision function is used to decide if the re-authentication certificate and its owner are authentic. On basis of that decision the user can get the authority to execute critical operations. </p><p>The finished prototype confirms that a re-authentication can be incorporated with the security architecture. The report also shows that the security status of the architecture is preserved. The performance of the prototype is rather difficult to prove since the prototype implementation only initialises the objects that are required to prove the security issues. A performance test can therefore never prove how the prototype will perform in an authentic environment. The performance is assumed to be adequate since it uses the same authentication function that is used by the security architecture.</p>

E-commerce has developed through the use of digital signatures, employing various forms of Public Key Infrastructure (PKI) to ensure the secure usage of digital signatures. Digital signatures are designed to facilitate the functions of traditional seals and handwritten signatures for the purposes of authentication, data integrity, and non-repudiation within the e-commerce environment. Historically, the authenticity of documentation has always been verified by the application of a recognisable visual stimulus to the document; however, the current digital signature regime overlooks the importance of this analogous sense of visualisation. One of the primary problems with existing digital signatures is that a digital signature does not "feel" like, or resemble, a traditional seal to the human observer, as it does not have a personal, recognisable, or aesthetic sense of visualisation. Currently, digital signatures, such as the OpenPGP (Pretty Good Privacy) digital signature, are attached to the end of an electronic document as a stream of printable ASCII characters. (RFC2440) This appears to the average user as a long, incomprehensible string of random characters offering no sense of identity or ownership by simple visual inspection. Additionally, digital signatures change each time they are applied, in contrast to traditional seals that remain consistent personal identifiers associated with individual signatories. The goal of this research is to promote enhancements to existing digital signature schemes in order to bridge the cultural gap between traditional seals and digital signatures. Culturally friendly features integrated into the digital signature have the potential to increase user acceptability of global e-commerce. This research investigates traditional seal cultures within the context of modern digital signatures, identifying the need to develop a new, culturally friendly, visualised digital signature scheme. The principles behind digital signatures are reviewed and the essential roles and responsibilities of a PKI are addressed. A practical analysis of PKI implementation is also essential. Taiwan is selected as the focus of this research since its heritage is deeply rooted in, and strongly adheres to the Chinese seal culture. The Taiwanese government is in the process of adapting the traditional seal certificate system to the electronic digital signature system. Therefore it is pertinent to review the PKI implementation and digital signatures applications in Taiwan in this study. The purpose of this research is to make the intangible digital signature virtually tangible; i.e., to incorporate visualisation into the current digital signature practice. This research defines new private extensions to the X.509 v3 certificate, recommending that conforming visualised digital signature applications should then be developed to generate and/or recognise visual digital certificates in support of the proposed visualised digital signature scheme. The processes of visualised digital signature creation and of verification through the application of the visualised digital certificate are then explained. This is accompanied by a model of system analysis for developers of conforming implementations of this specification. This allows developers the freedom to select appropriate developing tools. An analysis of this research evaluates the quality of integrity, security, interoperability, performance, and flexibility offered by this proposal.Future directions for furthering research development conclude this dissertation.

The purpose of this study was to analyze the characteristics of innovative designs within community college short-term certificate programs. Innovations in workforce training occur as stakeholders identify highly successful vocational programs and replicate those programs. Educational leaders in several states have developed short-term certificate programs to provide training that rewards students for completing modules of competencies en route to further certificates or degrees. Collective case studies were performed on the content of policy documents and of interviews with administrators at three California community colleges pertaining to the design of short-term vocational courses. The cross-case analysis showed agreement of the need for high levels of collaboration, development of fast-track programs to meet employability needs, and design of pathways to allow credits toward other certificates or degrees. Charts are displayed of data trends for short-term certificates earned by unit category over the years 1998-2007. Examples of short-term curricular schema are included in the appendices.

Context. An SSL encrypted client-server communication is necessary to maintain the security and privacy of the communication. For an SSL encryption to work, there should be a security certificate which has a certain expiry period. Periodic renewal of the certificate after its expiry is a waste of time and an effort on part of the company. Objectives. In this study, a new system has been developed and implemented, which sends a certificate during prior communication and does not wait for the certificate to expire. Automating the process to a certain extent was done to not compromise the security of the system and to speed up the process and reduce the downtime. Methods. Experiments have been conducted to test the new system and compare it to the old system. The experiments were conducted to analyze the packets and the downtime occurring from certificate renewal. Results. The results of the experiments show that there is a significant reduction in downtime. This was achieved due to the implementation of the new system and semi-automation Conclusions. The system has been implemented, and it greatly reduces the downtime occurring due to the expiry of the security certificates. Semi-Automation has been done to not hamper the security and make the system robust.

<p>Cultural bias in health assessment has been asserted in various scientific reports. The aim of this study was to determine whether ethnicity effects how patients are represented in such medical certificates that are needed to obtain a certain Swedish social insurance. The setting was an analysis of 18 medical certificates for patients whose parents were born in Sweden, respectively of 18 medical certificates of patients whose parents immigrated to Sweden from non European countries. The main objective was comparison of the two groups to test for ethnical heteronormative representations of the patients and their parents. The method used is mainly based on critical discourse analysis in combination with Fowlers (1996) semantic tools used to decipher disparity in the discourse. The text analysis is combined with theories of Said (1978), Johansson (1993) and de los Reyes (2006) regarding social representations of the ethnically non European “The Others”. Results of the study show that presentations of the two ethnical groups generally do differ both when it comes to representations of the patient as well as of the parent. Substantial differences are found in descriptions of patient aggression and asocial behaviour. The results render the conclusion that ethnical heteronormative representations can be found even in such documents that have the purpose of objectively certifying individual circumstances, conditions and difficulties.</p>

<p>Correct certificate revocation practices are essential to each public-key infrastructure. While there exist a number of protocols to achieve revocation in PKI systems, there has been very little work on the theory behind it: Which different types of revocation can be identified? What is the intended effect of a specific revocation type to the knowledge base of each entity?</p><p>As a first step towards a methodology for the development of reliable models, we present a graph-based formalism for specification and reasoning about the distribution and revocation of public keys and certificates. The model is an abstract generalization of existing PKIs and distributed in nature; each entity can issue certificates for public keys that they have confidence in, and distribute or revoke these to and from other entities.</p><p>Each entity has its own public-key base and can derive new knowledge by combining this knowledge with certificates signed with known keys. Each statement that is deduced or quoted within the system derives its support from original knowledge formed outside the system. When such original knowledge is removed, all statements that depended upon it are removed as well. Cyclic support is avoided through the use of support sets.</p><p>We define different revocation reasons and show how they can be modelled as specific actions. Revocation by removal, by inactivation, and by negation are all included. By policy, negative statements are the strongest, and positive are the weakest. Collisions are avoided by removing the weaker statement and, when necessary, its support.</p><p>Graph transformation rules are the chosen formalism. Rules are either interactive changes that can be applied by entities, or automatically applied deductions that keep the system sound and complete after the application of an interactive rule.</p><p>We show that the proposed model is sound and complete with respect to our definition of a valid state.</p> / Report code: LIU-TEK-LIC-2006:1

Cultural bias in health assessment has been asserted in various scientific reports. The aim of this study was to determine whether ethnicity effects how patients are represented in such medical certificates that are needed to obtain a certain Swedish social insurance. The setting was an analysis of 18 medical certificates for patients whose parents were born in Sweden, respectively of 18 medical certificates of patients whose parents immigrated to Sweden from non European countries. The main objective was comparison of the two groups to test for ethnical heteronormative representations of the patients and their parents. The method used is mainly based on critical discourse analysis in combination with Fowlers (1996) semantic tools used to decipher disparity in the discourse. The text analysis is combined with theories of Said (1978), Johansson (1993) and de los Reyes (2006) regarding social representations of the ethnically non European “The Others”. Results of the study show that presentations of the two ethnical groups generally do differ both when it comes to representations of the patient as well as of the parent. Substantial differences are found in descriptions of patient aggression and asocial behaviour. The results render the conclusion that ethnical heteronormative representations can be found even in such documents that have the purpose of objectively certifying individual circumstances, conditions and difficulties.

The increasing environmental threat because of unsustainable pollution levelshave forced E.U. to take further actions by enforcing directives in the electricity sector. The E.U. directives, enforced in 2002, aim to increase the level of electricity produced from renewable sources. In order to fulfill their received national target of green electricity, the E.U. members have, in most cases, either adopted a feed-in tariff or tradable green certificates. Since it is in a government’sinterest to minimize expenditure while still maximizing incentives when adopting a policy, this study has evaluated the cost-efficiency differences of a FIT and aTGC from a governmental perspective. This has been done by using two different models, one which measures total governmental expenditures in the energy sector and one which only measures the subsidies in the energy sector. The findings suggest that a TGC can be up to 159% more cost-efficient than a FIT, depending on how it is measured. The total expenditure model could establish the costefficiency differences with a significance of 5%, while the subsidy model could not establish the differences on a satisfying significance level

Baigiamajame magistro darbe nagrinėjamos naudotojo elektroninės tapatybės valdymo problemos, sprendimo būdai ir siūlomas praktinis sprendimo pritaikymas. Darbe analizuojami įvairūs tapatybės valdymo būdai bei lyginama programinė įranga, kuri gali padėti išspręsti elektroninės tapatybės valdymo problemas. Išanalizavus esamas Vilniaus Gedimino technikos tapatybės valdymo problemas, parinkta tinkamiausia programinė įranga, kuri labiausiai tinka galutinio sprendimo Vilniaus Gedimino technikos universitete įgyvendinimui. Sukurtas teorinis modelis galėtų būti įgyvendintas VGTU ir būtų susietas su LR el. parašu. Darbą sudaro 7 dalys : įvadas, naudotojų tapatybės valdymo analizė, esama elektroninės tapatybės būklė VGTU, asmens tapatybės valdymo sprendimų analizė, „IBM Tivoli identity management“ sprendimo pritaikymas VGTU, išvados, literatūros sąrašas. Darbo apimtis 63 p. teksto be priedų, 31 iliustr., 4 lent., 40 bibliografinių šaltinių. / In the final master theses the problems and solutions of user identity management are discussed, the practical application of proposed solution presented. Work analyses various identity management approaches as well as compares software dedicated to user identity management problems. After an analysis of Vilnius Gediminas Technical University user identity management problems, the most efficient software was selected, which is the most suitable solution for Vilnius Gediminas Technical University. The developed theoretical model could be applied in VGTU and connected with LR e. signature. Structure: introduction, analysis of user identity management, condition of VGTU user identity, identity management decision analysis, "IBM Tivoli Identity Management“ solutions for VGTU, conclusions, references. Thesis consists of: 63 p. text without appendixes, 31 pictures, 4 tables, 40 bibliographical entries.