This thesis examines distributed authentication in the process of controlling computing resources. We investigate user sign-on and two of the main authentication technologies that can be used to control a resource through authentication and providing additional security services. The problems with the existing sign-on scenario are that users have too much credential information to manage and are prompted for this information too often. Single Sign-On (SSO) is a viable solution to this problem if physical procedures are introduced to minimise the risks associated with its use. The Generic Security Services API (GSS-API) provides security services in a manner in- dependent of the environment in which these security services are used, encapsulating security functionality and insulating users from changes in security technology. The un- derlying security functionality is provided by GSS-API mechanisms. We developed the Secure Remote Password GSS-API Mechanism (SRPGM) to provide a mechanism that has low infrastructure requirements, is password-based and does not require the use of long-term asymmetric keys. We provide implementations of the Java GSS-API bindings and the LIPKEY and SRPGM GSS-API mechanisms. The Secure Authentication and Security Layer (SASL) provides security to connection- based Internet protocols. After finding deficiencies in existing SASL mechanisms we de- veloped the Secure Remote Password SASL mechanism (SRP-SASL) that provides strong password-based authentication and countermeasures against known attacks, while still be- ing simple and easy to implement. We provide implementations of the Java SASL binding and several SASL mechanisms, including SRP-SASL.

M.Sc. (Computer Science) / Information is a valuable resource in any organisation and more and more organisations are realising this and want efficient means to protect it against disclosure, modification or destruction. Although relatively efficient security methods have been available almost as long as information databases, they all provide additional cost. This cost does not only involve money but also cost in terms of system performance and management of information security. Any new information security model must also provide better management of information security. In this dissertation we present a model that provides information security and aims to lower the technical skills required to manage information security using this approach. In any business organisation we can describe each employee's duties. Put in other words, we can say that each employee has a specific business role in the organisation. In organisations with many employees there are typically many employees that have more or less the same duties in the organisation. This means that employees can be grouped according to their business roles. We use an employee's role as a description of his/her duties in a business organisation. ' Each role needs resources to perform its duties in the organisation. In terms of computer systems, each role needs computer resources such as printers. Most roles need access to data files in the organisation's database but it is not desirable to give all roles access to all data files. It is obvious that roles have specific privileges and restrictions in terms of information resources. Information security can be achieved by identifying the business roles in an organisation and giving these roles only the privileges needed to fulfill their business function and then assigning these roles to people (users of the organisation's computer system). This is called role-based security. People's business functions are related, for example clerks and clerk-managers are related in the sense that a clerk-manager is a manager of clerks. Business roles are related in the same way. For an information security manager to assign roles to users it is important to see this relationship between roles. In this dissertation we present this relationship using a lattice graph which we call a role lattice. The main advantage of this is that it is eases information security management...

M.Sc.(Computer Science) / The aim of this dissertation (referred to as thesis in the rest of the document) is to present authentication techniques that can be used to provide secure Internet commerce. The thesis presents techniques that can be used to authenticate human users at logon, as well as techniques that are used to authenticate user's PC and the host system during communication. In so doing, the thesis presents cryptography as the most popular approach to provide information security. Chapter 1 introduces the authentication problem, the purpose and the structure of the thesis. The inadequate security of the Internet prevents companies and users to conduct commerce over the Internet. Authentication is one of the means of providing secure Internet commerce. - Chapter 2 provides an overview of the Internet by presenting the Internet history, Internet infrastructure and the current services that are available on the Internet. The chapter defines Internet commerce and presents some of the barriers to the Internet commerce. Chapter 3 provides an overview of network and internetwork security model. The purpose of this chapter is to put authentication into perspective, in relation to the overall security model. Security attacks, security services and security mechanisms are defined in this chapter. The IBM Security Architecture is also presented. Chapter 4 presents cryptography as the popular approach to information security. The conventional encryption and public-key encryption techniques are used to provide some of the security services described in chapter 3. Chapter 5 presents various schemes that can be used to provide computer-to-computer authentication. These schemes are grouped into the following authentication functions: message encryption, cryptographic checksums, hash functions and digital signatures. Chapter 6 differentiates between one-way authentication schemes and mutual authentication schemes. The applicability of each approach depends on the communicating parties. Chapter 7 presents some of the popular and widely used open-systems technologies Internet protocols, which employ some of the schemes discussed in chapter 5 and chapter 6. These include the SSL, PCT, SHTTP, Kerberos, SESAME and SET. Chapter 8 discusses some of the enabling technologies that are used to provide human user authentication in a computer system. The password technology, the biometric technologies and the smart card technology are discussed. The considerations of selecting a specific technology are also discussed. Chapter 9 presents some of the techniques that can be used to authentication Internet users (human users) over the Internet. The techniques discussed are passwords, knowledge-based technique, voice recognition, smart cards, cellular based technique, and the technique that integrates Internet banking. Chapter 10 defines criteria on which the Internet user authentication techniques presented in chapter 9 can be measured against. The evaluation of each of the techniques is made against the specified criteria. In fact, this chapter concludes the thesis. Chapter 11 provides case studies on two of the techniques evaluated in chapter 10. Specifically, the insurance case study and the medical aid case studies are presented.

The motivation for this study argued that current information security ed- ucation systems are inadequate for educating all users of computer systems world wide in acting securely during their operations with information sys- tems. There is, therefore, a pervasive need for information security knowledge in all aspects of modern life. E-Learning 2.0 could possi- bly contribute to solving this problem, however, little or no knowledge currently exists regarding the suitability and practicality of using such systems to infer information security knowledge to learners.

Ph.D / This thesis looks at current security problems within open system environments, that is security problems within heterogeneous computer system environments that are interconnected via computer networks. Thereafter two security models, Kerberos and the Path Context Model, are considered together with their respective ability to address these security problems. Using concepts of the Path Context Model, a new security model, called MOSS (Model for Open System Security), is developed and it is shown how MOSS can address all the security problems identified. Two possible implementations of MOSS are then considered: the one is based on the concept of Static Security Agents (SSAs) for contemporary open system environments, and the other is based on the concept of Roaming Security Agents (RSAs) for object orientated open system environments. The research is concluded with a summary of possible future research considerations

The concept of privacy has proven difficult to analyze because of its subjective nature and susceptibility to psychological and contextual influences. This study challenges the concept of privacy as a valid construct for addressing individuals' concerns regarding online disclosure of personal information, based on the premise that underlying behavioral traits offer a more reliable and temporally stable measure of privacy-oriented behavior than do snapshots of environmentally induced emotional states typically measured by opinion polls. This study investigated the relationship of personality characteristics associated with individuals' general privacy-related behavior to their online privacy behaviors and concerns. Two latent constructs, Functional Privacy Orientation and Online Privacy Orientation, were formulated. Functional Privacy Orientation is defined as a general measure of individuals' perception of control over their privacy. It was measured using the factors General Disclosiveness, Locus of Control, Generalized Trust, Risk Orientation, and Risk Propensity as indicator variables. Online Privacy Orientation is defined as a measure of individuals' perception of control over their privacy in an online environment. It was measured using the factors Willingness to Disclose Online, Level of Privacy Concern, Information Management Privacy Concerns, and Reported Online Disclosure as indicator variables. A survey questionnaire that included two new instruments to measure online disclosure and a willingness to disclose online was used to collect data from a sample of 274 adults. Indicator variables for each of the latent constructs, Functional Privacy Orientation and Online Privacy Orientation, were evaluated using corrected item-total correlations, factor analysis, and coefficient alpha. The measurement models and relationship between Functional Privacy Orientation and Online Privacy Orientation were assessed using exploratory factor analysis and structural equation modeling respectively. The structural model supported the hypothesis that Functional Privacy Orientation significantly influences Online Privacy Orientation. Theoretical, methodological, and practical implications and suggestions for analysis of privacy concerns and behavior are presented.

In this study, the effect of computer use and Logo instruction on students' perceived control of computers and generalized perceived control was examined. Third and fourth grade students (<u>N</u>=90) in four intact groups, consisting of one treatment and one control group for each grade level, were pre- and posttested, using the computer control survey (CCS) and the Chi1dren's Nowicki-Strickland Locus of Control Scale (CNS-IE). A posttest measure of Logo achievement was obtained from the treatment students. Three way analyses of covariance, using the pretest scores as the covariate, were used to test for differences between the means of the independent variables group, grade, and gender for the dependent measures CCS and CNS-IE. Comparisons of adjusted posttest scores on these variables indicated that no significant differences existed between the groups. A linear association was found between Logo achievement and the children's perceived control of computers. Selected reliable items from the CNS-IE correlated with Logo achievement, although the full 40-item instrument did not. It is suggested that Logo instruction leading to Logo programming experiences may not produce in the children a sense of perceived power concerning the computer, nor lead to generalized LOC differences. Future researchers in this domain are advised to control for the internality of the sample and for the children's prior computer experience. Attention to the age/cognitive level of the sample, and length of treatment are suggested. / Ed. D. / incomplete_metadata

High processing time and implementation complexity of the fully homomorphic encryption schemes intrigued cryptographers to extend partially homomorphic encryption schemes to allow homomorphic computation for larger classes of polynomials. In this thesis, we study several public key and partially homomorphic schemes and discuss a recent technique for boosting linearly homomorphic encryption schemes. Further, we implement this boosting technique on CGS linearly homomorphic encryption scheme to allow one single multiplication as well as arbitrary number of additions on encrypted plaintexts. We provide MAGMA source codes for the implementation of the CGS scheme along with the boosted CGS scheme. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection

by Keith, Hang-kwong Mak. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 122-127). / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.4 / Chapter 2.1 --- Read/Write Model --- p.4 / Chapter 2.2 --- Abstract Data Type Model --- p.5 / Chapter 2.3 --- Overview of Semantics-Based Concurrency Control Protocols --- p.7 / Chapter 2.4 --- Concurrency Hierarchy --- p.9 / Chapter 2.5 --- Control Flow of the Strict Two Phase Locking Protocol --- p.11 / Chapter 2.5.1 --- Flow of an Operation --- p.12 / Chapter 2.5.2 --- Response Time of a Transaction --- p.13 / Chapter 2.5.3 --- Factors Affecting the Response Time of a Transaction --- p.14 / Chapter 3 --- Semantics-Based Concurrency Control Protocols --- p.16 / Chapter 3.1 --- Strict Two Phase Locking --- p.16 / Chapter 3.2 --- Conflict Relations --- p.17 / Chapter 3.2.1 --- Commutativity (COMM) --- p.17 / Chapter 3.2.2 --- Forward and Right Backward Commutativity --- p.19 / Chapter 3.2.3 --- Exploiting Context-Specific Information --- p.21 / Chapter 3.2.4 --- Relaxing Correctness Criterion by Allowing Bounded Inconsistency --- p.26 / Chapter 4 --- Related Work --- p.32 / Chapter 4.1 --- Exploiting Transaction Semantics --- p.32 / Chapter 4.2 --- Exploting Object Semantics --- p.34 / Chapter 4.3 --- Sacrificing Consistency --- p.35 / Chapter 4.4 --- Other Approaches --- p.37 / Chapter 5 --- Performance Study (Testbed Approach) --- p.39 / Chapter 5.1 --- System Model --- p.39 / Chapter 5.1.1 --- Main Memory Database --- p.39 / Chapter 5.1.2 --- System Configuration --- p.40 / Chapter 5.1.3 --- Execution of Operations --- p.41 / Chapter 5.1.4 --- Recovery --- p.42 / Chapter 5.2 --- Parameter Settings and Performance Metrics --- p.43 / Chapter 6 --- Performance Results and Analysis (Testbed Approach) --- p.46 / Chapter 6.1 --- Read/Write Model vs. Abstract Data Type Model --- p.46 / Chapter 6.2 --- Using Context-Specific Information --- p.52 / Chapter 6.3 --- Role of Conflict Ratio --- p.55 / Chapter 6.4 --- Relaxing the Correctness Criterion --- p.58 / Chapter 6.4.1 --- Overhead and Performance Gain --- p.58 / Chapter 6.4.2 --- Range Queries using Bounded Inconsistency --- p.63 / Chapter 7 --- Performance Study (Simulation Approach) --- p.69 / Chapter 7.1 --- Simulation Model --- p.70 / Chapter 7.1.1 --- Logical Queueing Model --- p.70 / Chapter 7.1.2 --- Physical Queueing Model --- p.71 / Chapter 7.2 --- Experiment Information --- p.74 / Chapter 7.2.1 --- Parameter Settings --- p.74 / Chapter 7.2.2 --- Performance Metrics --- p.75 / Chapter 8 --- Performance Results and Analysis (Simulation Approach) --- p.76 / Chapter 8.1 --- Relaxing Correctness Criterion of Serial Executions --- p.77 / Chapter 8.1.1 --- Impact of Resource Contention --- p.77 / Chapter 8.1.2 --- Impact of Infinite Resources --- p.80 / Chapter 8.1.3 --- Impact of Limited Resources --- p.87 / Chapter 8.1.4 --- Impact of Multiple Resources --- p.89 / Chapter 8.1.5 --- Impact of Transaction Type --- p.95 / Chapter 8.1.6 --- Impact of Concurrency Control Overhead --- p.96 / Chapter 8.2 --- Exploiting Context-Specific Information --- p.98 / Chapter 8.2.1 --- Impact of Limited Resource --- p.98 / Chapter 8.2.2 --- Impact of Infinite and Multiple Resources --- p.101 / Chapter 8.2.3 --- Impact of Transaction Length --- p.106 / Chapter 8.2.4 --- Impact of Buffer Size --- p.108 / Chapter 8.2.5 --- Impact of Concurrency Control Overhead --- p.110 / Chapter 8.3 --- Summary and Discussion --- p.113 / Chapter 8.3.1 --- Summary of Results --- p.113 / Chapter 8.3.2 --- Relaxing Correctness Criterion vs. Exploiting Context-Specific In- formation --- p.114 / Chapter 9 --- Conclusions --- p.116 / Bibliography --- p.122 / Chapter A --- Commutativity Tables for Queue Objects --- p.128 / Chapter B --- Specification of a Queue Object --- p.129 / Chapter C --- Commutativity Tables with Bounded Inconsistency for Queue Objects --- p.132 / Chapter D --- Some Implementation Issues --- p.134 / Chapter D.1 --- Important Data Structures --- p.134 / Chapter D.2 --- Conflict Checking --- p.136 / Chapter D.3 --- Deadlock Detection --- p.137 / Chapter E --- Simulation Results --- p.139 / Chapter E.l --- Impact of Infinite Resources (Bounded Inconsistency) --- p.140 / Chapter E.2 --- Impact of Multiple Resource (Bounded Inconsistency) --- p.141 / Chapter E.3 --- Impact of Transaction Type (Bounded Inconsistency) --- p.142 / Chapter E.4 --- Impact of Concurrency Control Overhead (Bounded Inconsistency) --- p.144 / Chapter E.4.1 --- Infinite Resources --- p.144 / Chapter E.4.2 --- Limited Resource --- p.146 / Chapter E.5 --- Impact of Resource Levels (Exploiting Context-Specific Information) --- p.149 / Chapter E.6 --- Impact of Buffer Size (Exploiting Context-Specific Information) --- p.150 / Chapter E.7 --- Impact of Concurrency Control Overhead (Exploiting Context-Specific In- formation) --- p.155 / Chapter E.7.1 --- Impact of Infinite Resources --- p.155 / Chapter E.7.2 --- Impact of Limited Resources --- p.157 / Chapter E.7.3 --- Impact of Transaction Length --- p.160 / Chapter E.7.4 --- Role of Conflict Ratio --- p.162

Typescript (photocopy). / Digitized by Kansas Correctional Industries / Department: Computer Science.