• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 6544
  • 1926
  • 919
  • 814
  • 686
  • 370
  • 179
  • 161
  • 154
  • 105
  • 93
  • 81
  • 79
  • 76
  • 76
  • Tagged with
  • 14804
  • 2967
  • 2026
  • 1873
  • 1450
  • 1376
  • 1343
  • 1298
  • 1259
  • 1165
  • 1154
  • 1146
  • 1073
  • 1030
  • 949
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Secure Integrated Routing and Localization in Wireless Optical Sensor Networks

Okorafor, Unoma Ndili 15 May 2009 (has links)
Wireless ad hoc and sensor networks are envisioned to be self-organizing and autonomous networks, that may be randomly deployed where no fixed infrastructure is either feasible or cost-effective. The successful commercialization of such networks depends on the feasible implementation of network services to support security-aware applications. Recently, free space optical (FSO) communication has emerged as a viable technology for broadband distributed wireless optical sensor network (WOSN) applications. The challenge of employing FSO include its susceptibility to adverse weather conditions and the line of sight requirement between two communicating nodes. In addition, it is necessary to consider security at the initial design phase of any network and routing protocol. This dissertation addresses the feasibility of randomly deployed WOSNs employing broad beam FSO with regard to the network layer, in which two important problems are specifically investigated. First, we address the parameter assignment problem which considers the relationship amongst the physical layer parameters of node density, transmission radius and beam divergence of the FSO signal in order to yield probabilistic guarantees on network connectivity. We analyze the node isolation property of WOSNs, and its relation to the connectivity of the network. Theoretical analysis and experimental investigation were conducted to assess the effects of hierarchical clustering as well as fading due to atmospheric turbulence on connectivity, thereby demonstrating the design choices necessary to make the random deployment of the WOSN feasible. Second, we propose a novel light-weight circuit-based, secure and integrated routing and localization paradigm within the WOSN, that leverages the resources of the base station. Our scheme exploits the hierarchical cluster-based organization of the network, and the directionality of links to deliver enhanced security performance including per hop and broadcast authentication, confidentiality, integrity and freshness of routing signals. We perform security and attack analysis and synthesis to characterize the protocol’s performance, compared to existing schemes, and demonstrate its superior performance for WOSNs. Through the investigation of this dissertation, we demonstrate the fundamental tradeoff between security and connectivity in WOSNs, and illustrate how the transmission radius may be used as a high sensitivity tuning parameter to balance there two metrics of network performance. We also present WOSNs as a field of study that opens up several directions for novel research, and encompasses problems such as connectivity analysis, secure routing and localization, intrusion detection, topology control, secure data aggregation and novel attack scenarios.
32

Zhongguo she hui bao xian zhi du zhi yan jiu

Xu, Huashun. January 1900 (has links)
Thesis (M.A.)--Si li Zhongguo wen hua xue yuan. / eContent provider-neutral record in process. Description based on print version record.
33

End-User Computing development strategy for the Republic of Indonesia in the 90's

Prananto, Paulus. January 1990 (has links) (PDF)
Thesis (M.S. in Management and M.S. in Information Systems)--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Bui, Tung ; Dresser, Cynthia H. "September 1990." Description based on title screen as viewed on December 17, 2009. DTIC Descriptor(s): Data Processing, Information Systems, Theses, Costs, Indonesia, Information Centers, Resources, Power, Architecture, Deterrence, Propagation, Viability. DTIC Identifier(s): Management Information Systems, User Needs, Military Forces(Foreign), Indonesia, Scenarios, Theses, National Security. Author(s) subject terms: End-user Computing, Information Centers, Development strategy for ABRI in the 90's. Includes bibliographical references (p. 117-120). Also available in print.
34

Using the bootstrap concept to build an adaptable and compact subversion artifice /

Lack, Lindsey A. January 2003 (has links) (PDF)
Thesis (M.S. in Computer Science)--Naval Postgraduate School, June 2003. / Thesis advisor(s): Cynthia E. Irvine, Roger R. Schell. Includes bibliographical references (p. 69-71). Also available online.
35

Query and access control over encrypted databases

Zhang, Ye, 张叶 January 2010 (has links)
published_or_final_version / Computer Science / Master / Master of Philosophy
36

Security and computability in database applications

Wong, Wai-kit, 王偉傑 January 2011 (has links)
published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy
37

Data flow and heap analysis with application to privilege escalation vulnerability scanning and software theft detection

Chan, Ping-fai., 陳秉暉. January 2013 (has links)
Static and dynamic program analysis techniques are important research areas in software security. Static analysis helps us locate vulnerabilities in a software by looking at the source code. Dynamic analysis helps us reason about the behavior of the software from information gathered at run-time. In this thesis, we are focusing on data flow analysis and heap analysis which are key static and dynamic program analysis techniques respectively. In the first part of this thesis, we aim at detecting vulnerabilities in Android applications which have capability leaks. The security of the Android platform relies mainly on sandboxing applications and restricting their capabilities such that no application, by default, can perform any operations that would adversely impact other applications, the operating system, or the user. However, a recent research reported that a genuine but vulnerable application may leak its capabilities. When being leveraged, other applications can gain extra capabilities which they are not granted originally. We present DroidChecker, an Android application analyzing tool which searches for the aforementioned vulnerability in Android applications. DroidChecker uses interprocedural control flow graph searching and static taint checking to detect exploitable data paths in an Android application. We analyzed more than 1100 Android applications using DroidChecker and found 6 previously unknown vulnerable applications including the renowned Adobe Photoshop Express application. We also developed a malicious application that exploits the previously unknown vulnerability found in the Adobe Photoshop Express application. We showed that the malicious application, which is not granted any permissions, can access contacts on the phone with just a few lines of code. In the second part of this thesis, we explore the use of heap analysis to extract software birthmarks. There are techniques like code obfuscation and watermarking which can make the source code of a program difficult to understand by humans and prove the ownership of the program. However, code obfuscation cannot avoid the source code being copied and a watermark can be defaced. A birthmark is a group of unique characteristics a program possesses that can be used to identify the program. We propose two novel dynamic birthmark systems based on the run-time heap. A dynamic birthmark is one that is extracted when the program is executing. Since it is based on the run-time behavior of the program, semantics-preserving transformations of the code like obfuscation cannot defeat dynamic birthmarks. In this regard, dynamic birthmarks are more robust compared with static birthmarks. To the best of our knowledge, these are the first birthmark systems using heap analysis as the underlying technique. The basic idea is to take snapshots of the heap while the program is running. From the snapshots, heap graphs are constructed to model the referencing structure between objects. After going through some filtering and referencing processes, they become the birthmarks. The two birthmark systems have been devised to extract birthmarks for Java programs and JavaScript programs respectively. While the underlying ideas of the two birthmark systems are similar, the differences in nature of the two programming languages led to different implementation designs. / published_or_final_version / Computer Science / Doctoral / Doctor of Philosophy
38

Algebraic coded cryptosystems

Gibson, John Keith January 1996 (has links)
No description available.
39

Nodal governance and security provision: the University of Manitoba Security Service

Hanly, Mark 30 March 2012 (has links)
Security has consistently been identified as a State prerogative whereby the State holds a monopoly on the governance of all such activities within itself. This understanding has been challenged over the past two decades by the proliferation of security providers in both state and non-state forms. The frameworks of anchored pluralism and private governance have expanded criminologists’ understanding of security governance, moving it beyond a state-centric model. The nodal governance paradigm encompasses these concepts and develops them by emphasizing an increasing ‘pluralisation’ of security governance. This study focuses on the University of Manitoba Security Service as an institution, mapping the ways in which it forms relationships with other security nodes to form a complex system of governance. This thesis illuminates that the University of Manitoba Security Service is a node of security governance, and thus it uses both formal and informal mechanisms to network with other security bodies.
40

Connect street light control devices in a secure network

Lykouropoulos, Efstathios, Kostoulas, Andreas, Jumaa, Zainab January 2015 (has links)
Wireless communications is a constantly progressing technology in network engineering society, creating an environment full of opportunities that are targeting in financial growth, quality of life and humans prosperity. Wireless security is the science that has as a goal to provide safe data communication between authorized users and prevent unauthorized users from gaining access, deny access, damage or counterfeit data in a wireless environment. In order to success it uses layers of protection that consist of software and hardware mechanisms that are able to monitor network’s behavior and in coordination provide a safe and secure environment for the user. In this thesis, a scientific research will be conducted in a given wireless network topology designed for an original application. This is about an intelligent street lightning system and it has already been implemented by Greinon Engineering which is the company that we are cooperating with. It is a matter of great importance that this thesis was conducted under real life criteria and in cooperation with an engineering company. This means that our programming, our ideas, our study research were all rotated and concentrated in certain type of hardware – software and network topology. In this thesis there is a detailed overview of basic wireless security mechanisms – vulnerabilities – types of attacks and countermeasures focused on 802.11b protocol. Moreover there will be security weak point’s analysis on the given industrial network; our proposals to protect and secure this network based on our threat analysis of the current system. There is an analysis on the most up to date VPN security implementations and reasoning that guided our team to conclude in a specific procedure - protocol and implementation, including limitation factors – obstacles faces during this procedure. During this research iterative approach in procedures – ideas and implementation attempts is followed. Basic goal is to provide security solutions that are easy applicable, low cost, easy to maintain and monitor.

Page generated in 0.0781 seconds