by Shum Kwan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 30-32). / Abstracts in English and Chinese. / Acknowledgement --- p.ii / Abstract --- p.iii / □ □ --- p.iv / Chapter 1 . --- Introduction --- p.1 / Chapter 1.1 --- Introduction to topic --- p.1 / Chapter 1.2 --- What is proxy signature? --- p.2 / Chapter 1.3 --- Terminologies in proxy signature --- p.2 / Chapter 1.4 --- Levels of delegation --- p.3 / Chapter 1.5 --- Previous work on Proxy Signature --- p.4 / Chapter 1.6 --- Our Contributions --- p.4 / Chapter 1.7 --- Thesis Organization --- p.4 / Chapter 2. --- Backgroun d --- p.6 / Chapter 2.1 --- Digital Signature --- p.6 / Chapter 2.2 --- Digital Certificate and CA --- p.6 / Chapter 2.3 --- Hash Functions --- p.7 / Chapter 2.4 --- Bit commitment --- p.7 / Chapter 3. --- Brief introduction to Our Result --- p.8 / Chapter 3.1 --- A Proxy Signature Scheme with Proxy Signer Privacy Protection --- p.8 / Chapter 3.2 --- Applications of Proxy Signature --- p.9 / Chapter 4. --- Detail Explanation of Certified Alias and its Application on Proxy Signature --- p.10 / Chapter 4.1 --- Introduction --- p.10 / Chapter 4.2 --- Protecting Signer Privacy Using Certified Alias Definition 4.2.3 --- p.10 / Chapter 4.3 --- Constructing Proxy signature Scheme by Consecutive Execution of Cryptographic Primitives (Scheme CE) --- p.11 / Chapter 4.4 --- Constructing Proxy signature Scheme by Direct Form Equations (Scheme DF) --- p.15 / Chapter 4.5 --- Comparison between scheme CE and scheme DF --- p.19 / Chapter 4.6 --- Chapter Summary --- p.20 / Chapter 5 . --- Applications of Proxy Signature with Proxy Signer Privacy Protection --- p.21 / Chapter 5.1 --- Secure Mobile agent Signature with Itinerary Privacy --- p.21 / Chapter 5.1.1 --- Introduction to Mobile Agent --- p.21 / Chapter 5.1.2 --- "Review on Lee, et al. strong non-designated proxy signature scheme for mobile agents" --- p.21 / Chapter 5.1.3 --- Constructing Signature scheme for Mobile Agent using Proxy signature with Proxy Signer Privacy Protection --- p.22 / Chapter 5.1.4 --- Remarks --- p.23 / Chapter 5.2 --- Group Signature with Unlimited Group Size --- p.24 / Chapter 5.2.1 --- Introduction to group signature --- p.24 / Chapter 5.2.2 --- Constructing group signature scheme using certified alias --- p.24 / Chapter 5.2.4 --- Remarks --- p.26 / Chapter 5.3 --- Chapter Summary --- p.27 / Chapter 6. --- Conclusions --- p.28 / Appendix: Paper derived from this thesis --- p.29 / Bibliography --- p.30

Signcryption is a new cryptographic primitive which simultaneously provides both confidentiality and authenticity. Previously, these two goals had been considered separately, with encryption schemes providing confidentiality and signature schemes providing authenticity. In cases where both were required, the encryption and signature operations were simply sequentially composed. In 1997, Zheng demonstrated that by combining both goals into a single primitive, it is possible to achieve significant savings both in computational and communication overhead. Since then, a wide variety of signcryption schemes have been proposed. In this thesis, we present a number of the proposed signcryption schemes in terms of a common framework. For the most part, the material has been previously presented in various research papers, but some previously omitted proofs have been filled in here. We begin by giving a formal definition of the signcryption primitive, complete with a security model. Then we look at some of the various proposed signcryption schemes, and consider their relative advantages and disadvantages. Finally, we look ahead at what future progress might be made in the field.

Signcryption is a new cryptographic primitive which simultaneously provides both confidentiality and authenticity. Previously, these two goals had been considered separately, with encryption schemes providing confidentiality and signature schemes providing authenticity. In cases where both were required, the encryption and signature operations were simply sequentially composed. In 1997, Zheng demonstrated that by combining both goals into a single primitive, it is possible to achieve significant savings both in computational and communication overhead. Since then, a wide variety of signcryption schemes have been proposed. In this thesis, we present a number of the proposed signcryption schemes in terms of a common framework. For the most part, the material has been previously presented in various research papers, but some previously omitted proofs have been filled in here. We begin by giving a formal definition of the signcryption primitive, complete with a security model. Then we look at some of the various proposed signcryption schemes, and consider their relative advantages and disadvantages. Finally, we look ahead at what future progress might be made in the field.

Synchronous generators play a vital role in power systems. One of the major mechanical faults in synchronous generators is related to bearings. The popular vibration analysis method has been utilized to detect bearing faults for years. However, bearing health monitoring based on vibration analysis is expensive. One of the reasons is because vibration analysis requires costly vibration sensors and the extra costs associated with its proper installation and maintenance. This limitation prevents continuous bearing condition monitoring, which gives better performance for rolling element bearing fault detection, compared to the periodic monitoring method that is a typical practice for bearing maintenance in industry. Therefore, a cost effective alternative is necessary. In this study, a sensorless bearing fault detection method for synchronous generators is proposed based on the analysis of electrical signatures, and its bearing fault detection capability is demonstrated. Experiments with staged bearing faults are conducted to validate the effectiveness of the proposed fault detection method. First, a generator test bed with an in- situ bearing damage device is designed and built. Next, multiple bearing damage experiments are carried out in two vastly different operating conditions in order to obtain statistically significant results. During each experiment, artificially induced bearing current causes accelerated damage to the front bearing of the generator. This in-situ bearing damage process entirely eliminates the necessity of disassembly and reassembly of the experimental setup that causes armature spectral distortions. The electrical fault indicator is computed based on stator voltage signatures without the knowledge of machine and bearing specific parameters. Experimental results are compared using the electrical indicator and a vibration indicator that is calculated based on measured vibration data. The results indicate that the electrical indicator can be used to analyze health degradation of rolling element bearings in synchronous generators in most instances. Though the vibration indicator enables early bearing fault detection, it is found that the electrical fault indicator is also capable of detecting bearing faults well before catastrophic bearing failure.

Digital watermarking is one of the most popular technologies for protecting the ownerships of digital contents or products. By embedding digital watermarks into digital contents, the owners of the contents can convince the judge or the trusted third party of their ownership of the contents. However, some attacks, such as the binding attacks and the men-in-the-middle attacks, are threatening the security of the watermarking mechanisms. Moreover, that the privacy of content buyers is not fully protected or the dispute between the buyers and the sellers cannot be fairly resolved also reduce the quality of the services. Although several buyer-seller watermarking protocols have been introduced in the literature, none can cope with all of the above problems. In this thesis, we will propose a novel buyer-seller watermarking protocol that can resolve the dispute between the buyers and the sellers fairly. Furthermore, not only is the proposed protocol immune to all of the known attacks, but it is truly buyer anonymous as well.

Thèse de doctorat--Signal et images--Paris--ENST, 2005. / Bibliogr. p. 213-222. Résumé en français et en anglais.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains ix, 57 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 49-51).

With the increasing use of Intrusion Detection Systems (IDS) as a core component of network security, a vast array of competing products have appeared to fulfil the role of reliably detecting potential breaches of security in a network. The domain of detecting intrusions is large. This leads to products which are better at detecting some intrusions than others, and so to the use of multiple different types of IDS within a network. This typical usage, combined with the common practice of using IDS at multiple points in the network, requires sophisticated management of heterogenous alerts from multiple sources. This management should enable correlation of alerts with the goal of better detecting attacks, and reducing the monitoring workload on administrators. This thesis presents an architecture utilising commodity components and the Intrusion Detection Message Exchange Format (IDMEF) to enable this type of alert management. A signature scheme for the specification of patterns of alerts that indicate multi-step attacks is given, and a methodology for analysing alerts using the architecture that was developed. The final outcomes are a signature system and collection of tools integrated in a GUI management interface to aid in the detection of attacks, and the results of utilising these tools on a series of experiments in attack detection.

Thesis (Ph. D.)--University of North Texas, Dec., 2008. / Title from title page display. Includes bibliographical references.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.