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Thesis. 1978. M.S.--Massachusetts Institute of Technology. Alfred P. Sloan School of Management. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Bibliography: leaf 79. / M.S.

Yu Haitao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 71). / Abstracts in English and Chinese. / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Thesis organization --- p.6 / Chapter Chapter 2. --- Conventional password authentication and backdoor password schemes --- p.7 / Chapter 2.1 --- Password and password authentication --- p.7 / Chapter 2.1.1 --- Introduction to password and its security problems --- p.7 / Chapter 2.1.2 --- Front-door passwords vs. backdoor passwords --- p.8 / Chapter 2.1.3 --- Dynamic passwords vs. static passwords --- p.9 / Chapter 2.2 --- Forgotten-password problem --- p.10 / Chapter Chapter 3. --- Introduction to Cryptography --- p.12 / Chapter 3.1 --- Introduction to information security --- p.12 / Chapter 3.2 --- Conventional cryptography --- p.16 / Chapter 3.3 --- Public-key cryptography --- p.21 / Chapter 3.4 --- RSA cryptosystem --- p.24 / Chapter 3.5 --- One-way function --- p.27 / Chapter 3.6 --- Digital signature --- p.30 / Chapter 3.7 --- Secret sharing --- p.34 / Chapter 3.8 --- Zero-knowledge proof --- p.34 / Chapter 3.9 --- Key management --- p.36 / Chapter 3.9.1 --- Key distribution in conventional cryptography --- p.36 / Chapter 3.9.2 --- Distribution of public keys --- p.39 / Chapter Chapter 4. --- A secure one-use dynamic backdoor password system based on Public Key Cryptography --- p.42 / Chapter 4.1 --- System objectives --- p.42 / Chapter 4.2 --- Simple system and analysis --- p.45 / Chapter 4.2.1 --- System diagram --- p.45 / Chapter 4.2.2 --- System protocol --- p.46 / Chapter 4.2.3 --- Applied technologies --- p.50 / Chapter 4.2.4 --- System security analysis --- p.52 / Chapter 4.3 --- Multi-user system and analysis --- p.55 / Chapter 4.3.1 --- Modification to the system diagram --- p.56 / Chapter 4.3.2 --- Modification to the system protocol --- p.57 / Chapter 4.3.3 --- System analysis for multi-user system --- p.64 / Chapter 4.4 --- Applicable modes and analysis --- p.66 / Chapter 4.5 --- Conclusion --- p.68 / Chapter Chapter 5. --- Conclusion --- p.69 / Bibliography --- p.71 / Appendix --- p.72 / Chapter A. --- Algorithm of MD5 --- p.72 / Chapter B. --- Algorithm of DSA --- p.76 / Chapter C. --- Algorithm of RSA --- p.79

Yuen Tsz Hon. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 109-122). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / List of Notations --- p.viii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Identity Based Cryptography --- p.3 / Chapter 1.2 --- Hierarchical Identity Based Cryptosystem --- p.4 / Chapter 1.3 --- Our contributions --- p.5 / Chapter 1.4 --- Publications --- p.5 / Chapter 1.4.1 --- Publications Produced from This Thesis --- p.5 / Chapter 1.4.2 --- Publications During Author's Study in the Degree --- p.6 / Chapter 1.5 --- Thesis Organization --- p.6 / Chapter 2 --- Background --- p.8 / Chapter 2.1 --- Complexity Theory --- p.8 / Chapter 2.1.1 --- Order Notation --- p.8 / Chapter 2.1.2 --- Algorithms and Protocols --- p.9 / Chapter 2.1.3 --- Relations and Languages --- p.11 / Chapter 2.2 --- Algebra and Number Theory --- p.12 / Chapter 2.2.1 --- Groups --- p.12 / Chapter 2.2.2 --- Elliptic Curve --- p.13 / Chapter 2.2.3 --- Pairings --- p.14 / Chapter 2.3 --- Intractability Assumptions --- p.15 / Chapter 2.4 --- Cryptographic Primitives --- p.18 / Chapter 2.4.1 --- Public Key Encryption --- p.18 / Chapter 2.4.2 --- Digital Signature --- p.19 / Chapter 2.4.3 --- Zero Knowledge --- p.21 / Chapter 2.5 --- Hash Functions --- p.23 / Chapter 2.6 --- Random Oracle Model --- p.24 / Chapter 3 --- Literature Review --- p.26 / Chapter 3.1 --- Identity Based Signatures --- p.26 / Chapter 3.2 --- Identity Based Encryption --- p.27 / Chapter 3.3 --- Identity Based Signcryption --- p.27 / Chapter 3.4 --- Identity Based Blind Signatures --- p.28 / Chapter 3.5 --- Identity Based Group Signatures --- p.28 / Chapter 3.6 --- Hierarchical Identity Based Cryptography --- p.29 / Chapter 4 --- Blind Identity Based Signcryption --- p.30 / Chapter 4.1 --- Schnorr's ROS problem --- p.31 / Chapter 4.2 --- BIBSC and Enhanced IBSC Security Model --- p.32 / Chapter 4.2.1 --- Enhanced IBSC Security Model --- p.33 / Chapter 4.2.2 --- BIBSC Security Model --- p.36 / Chapter 4.3 --- Efficient and Secure BIBSC and IBSC Schemes --- p.38 / Chapter 4.3.1 --- Efficient and Secure IBSC Scheme --- p.38 / Chapter 4.3.2 --- The First BIBSC Scheme --- p.43 / Chapter 4.4 --- Generic Group and Pairing Model --- p.47 / Chapter 4.5 --- Comparisons --- p.52 / Chapter 4.5.1 --- Comment for IND-B --- p.52 / Chapter 4.5.2 --- Comment for IND-C --- p.54 / Chapter 4.5.3 --- Comment for EU --- p.55 / Chapter 4.6 --- Additional Functionality of Our Scheme --- p.56 / Chapter 4.6.1 --- TA Compatibility --- p.56 / Chapter 4.6.2 --- Forward Secrecy --- p.57 / Chapter 4.7 --- Chapter Conclusion --- p.57 / Chapter 5 --- Identity Based Group Signatures --- p.59 / Chapter 5.1 --- New Intractability Assumption --- p.61 / Chapter 5.2 --- Security Model --- p.62 / Chapter 5.2.1 --- Syntax --- p.63 / Chapter 5.2.2 --- Security Notions --- p.64 / Chapter 5.3 --- Constructions --- p.68 / Chapter 5.3.1 --- Generic Construction --- p.68 / Chapter 5.3.2 --- An Instantiation: IBGS-SDH --- p.69 / Chapter 5.4 --- Security Theorems --- p.73 / Chapter 5.5 --- Discussions --- p.81 / Chapter 5.5.1 --- Other Instantiations --- p.81 / Chapter 5.5.2 --- Short Ring Signatures --- p.82 / Chapter 5.6 --- Chapter Conclusion --- p.82 / Chapter 6 --- Hierarchical IBS without Random Oracles --- p.83 / Chapter 6.1 --- New Intractability Assumption --- p.87 / Chapter 6.2 --- Security Model: HIBS and HIBSC --- p.89 / Chapter 6.2.1 --- HIBS Security Model --- p.89 / Chapter 6.2.2 --- Hierarchical Identity Based Signcryption (HIBSC) --- p.92 / Chapter 6.3 --- Efficient Instantiation of HIBS --- p.95 / Chapter 6.3.1 --- Security Analysis --- p.96 / Chapter 6.3.2 --- Ordinary Signature from HIBS --- p.101 / Chapter 6.4 --- Plausibility Arguments for the Intractability of the OrcYW Assumption --- p.102 / Chapter 6.5 --- Efficient HIBSC without Random Oracles --- p.103 / Chapter 6.5.1 --- Generic Composition from HIBE and HIBS --- p.104 / Chapter 6.5.2 --- Concrete Instantiation --- p.105 / Chapter 6.6 --- Chapter Conclusion --- p.107 / Chapter 7 --- Conclusion --- p.108 / Bibliography --- p.109

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Ke, Bingwen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 52-54). / Abstracts in Chinese and English. / Abstract --- p.3 / Acknowledgement --- p.5 / Content --- p.6 / Table of Figures --- p.8 / Chapter Chapter 1 --- Introduction --- p.9 / Chapter 1.1 --- Motivations and Contributions --- p.9 / Chapter 1.2 --- Organization of the Thesis --- p.11 / Chapter Chapter 2 --- Background --- p.12 / Chapter 2.1 --- Multiple-Input-Multiple-Output (MIMO) System --- p.12 / Chapter 2.1.1 --- Basic MIMO Structure --- p.12 / Chapter 2.1.2 --- Multiple User Detection (MUD) in MIMO Networks --- p.14 / Chapter 2.2 --- IEEE 802.11 --- p.16 / Chapter 2.2.1 --- CSMA/CA in 802.11 --- p.16 / Chapter 2.2.2 --- CSMA/CA(k) in 802.1 In --- p.18 / Chapter 2.2.3 --- Co-channel Transmission in MIMO WLAN --- p.19 / Chapter Chapter 3 --- Channel Correlation in MIMO Ad Hoc Networks --- p.20 / Chapter 3.1 --- Introduction of Channel Correlation --- p.20 / Chapter 3.2 --- Channel Correlation Threshold --- p.25 / Chapter Chapter 4 --- MAC with SINR Threshold --- p.28 / Chapter Chapter 5 --- Performance Evaluation of MWST in Fully-Connected Networks --- p.33 / Chapter Chapter 6 --- MAC with SINR Threshold (MWST) in Partially-Connected Networks --- p.38 / Chapter 6.1 --- Hidden Link Problem in Partially-Connected Networks --- p.38 / Chapter Chapter 7 --- Performance Evaluation in Partially-Connected Networks --- p.42 / Chapter 7.1 --- Fairness Issues in CSMA/CA(k) --- p.42 / Chapter 7.2 --- Fairness Performance of MWST --- p.45 / Conclusion --- p.50 / References --- p.52

Chan, Hing Pan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 107-109). / Abstracts in English and Chinese. / Chapter Chapter 1 - --- Introduction --- p.1 / Chapter Chapter 2 - --- Background --- p.3 / Chapter 2.1 --- IEEE 802.11 MAC Protocol --- p.3 / Chapter 2.2 --- Related Work --- p.5 / Chapter Chapter 3 - --- Design Principles --- p.8 / Chapter Chapter 4 - --- Load-Adaptive Transmission Scheduling --- p.11 / Chapter 4.1 --- Contention Period (CP) --- p.14 / Chapter 4.2 --- Service Period (SP) --- p.22 / Chapter Chapter 5 - --- Synchronization --- p.27 / Chapter 5.1 --- Slot Boundary Detection --- p.27 / Chapter 5.2 --- Period Boundary Detection --- p.29 / Chapter 5.3 --- Period Identification --- p.30 / Chapter 5.4 --- Exception Handling --- p.62 / Chapter Chapter 6 - --- Performance Analysis --- p.70 / Chapter Chapter 7 - --- Performance Evaluations --- p.73 / Chapter 7.1 --- Parameter Tuning --- p.75 / Chapter 7.2 --- CBR UDP Traffic --- p.82 / Chapter 7.3 --- TCP Traffic --- p.94 / Chapter 7.4 --- Performance in Multi-hop Networks --- p.101 / Chapter Chapter 8 - --- Conclusions --- p.105 / Bibliography --- p.107

Thesis (M.Com. (Information Systems))--University of the Witwatersrand, Faculty of Commerce, Law and Management, School of Economic and Business Sciences, 2017 / Although studies have been conducted on the effectiveness of different types of filtering software, limited knowledge is available on parents’ use of strategies to monitor their children’s activities online. Thus, identifying understanding parents’ use of strategies to monitor children’s activities online and the extent in which parents use content filtering software will contribute to the body of knowledge. The purpose of this study is to understand parent’s use of strategies to monitor children’s activities online and the extent in which they use content filtering software in Gauteng Province, South Africa. The study adopted a Social Cognitive Theory to develop a conceptual framework and identify existing theoretical concepts. The conceptual framework adapted Bandura’s (2001) framework to inform data analysis. Data were collected through semi-structured interviews and qualitative, thematic content analysis was used for data analyses. The results of the study indicated that parents do use various strategies to monitor children’s activities online and further apply knowledge, experience, and social support as a rationale for using those strategies. The study further revealed that there is a gap between parents, technology industry and government regarding the use of content filtering software. Thus, the study recommends parents, industry and government work together to protecting children online through various strategies and address the concerns regarding the use of content filtering software. Parents’ need to understand the importance of content filtering software and discuss this with their children to be able to protect them online without restricting access to relevant information. Keywords: Harmful content, blocking, strategies, filtering, online content, software, use, non-use, strategies / GR2018

Collaborative environments allow users to share and access data across networks spanning multiple administrative domains and beyond organisational boundaries. This poses several security concerns such as data confidentiality, data privacy and threats to improper data usage. Traditional access control mechanisms focus on centralised systems and implicitly assume that all resources reside in the one domain. This serves as a critical limitation for inter-organisational collaborative environments, which are characteristically decentralised, distributed and heterogeneous. A consequence of the lack of suitable access control mechanisms for inter-organisational collaborative environments is that data owners relinquish all control over data they release. In these environments, we can reasonably consider more complex cases where documents may have multiple contributors, all with differing access control requirements. Facilitating such cases, as well as maintaining control over the document’s content, its structure and its flow path as it circulates through multiple administrative domains, is a non-trival issue. This thesis proposes an architecture model for specifying and enforcing access control restrictions on sensitive data that follows a pre-defined inter-organisational workflow. Our approach is to embed access control enforcement within the workflow object (e.g. the circulating document containing sensitive data) as opposed to relying on each administrative domain to enforce the access control policies. The architecture model achieves this using cryptographic access control – a concept that relies on cryptography to enforce access control policies.

In this thesis, novel solutions are proposed for key management issues in mobile ad hoc networks. Presented Hierarchical Binary Tree (HBT) based model is distributed, self-organizing, scalable and does not employ online key distribution authority or group manager. Two different group authentication and group key establishment protocols are proposed for the users who form an ad hoc group with distributed trust model. Initially proposed protocols are based on public key cryptography and do not use specific algorithm. However, members can establish the keys faster with proposed customized hybrid scheme which combines elliptic curve cryptography, modular squaring operations and secret key encryption algorithm. Proposed HBT based model provides complete backward and forward security in case of modification in membership and it has comparable efficiency to the other HBT based schemes which employ real time key distribution authority. Mutual authentication and link encryption can be achieved in wireless sensor network only with public key cryptography if there are no pre-distributed keys. However, constraints in resources make fully public key operations not affordable on sensor. Three different authenticated key establishment protocols are proposed with an objective of being respectful to constraints. Sensor needs to make only modular or cyclic convolution multiplications, and expensive public key decryption operation is executed at the data processing station side. Schemes require small size of code and achieve the least sensor processing time in comparison with fully public key cryptography based protocols. / Graduation date: 2005