Thesis( M. A. (Computer Science)) -- University of Limpopo , 2021 / In Software Defined Cognitive Radio Network (SDCRN), network security is a significant issue. This issue arises when Software Defined Network (SDN) architecture integrates with the Cognitive Radio Network (CRN) technology. SDN is designed to improve network resource management, while CRN technology is meant at improving spectrum management. These technologies are vulnerable to several malicious attacks. These attacks include Distributed Denial of Service (DDoS) and Primary User Emulation (PUE). Both the DDoS and PUE can be disrupt services in the SDCRN. To curb these attacks, schemes which hardens the security of SDCRN need to be designed. Thus, in this study we propose a security mechanism called Extreme_Controller_Mechanism (XCM) that reduce the effects of DDoS and PUE. The proposed XCM scheme was designed and evaluated in three simulation environment, the OMNeT++, Octave, and MATLAB simulators. The SDCRN data set was generated using the Neural Network back propagation algorithms. The data set was then used in Matlab to evaluate the effectiveness of the prosed XCM scheme. XCM proved to be effective and efficient at detection and prevention of DDoS and PUE attacks in SDCRN. In terms of memory and processor utilisation, XCM proved to the best when compared to other schemes such as the Advanced Support Vector Machine (ASVM) and deep learning convolution network (CDLN). But in terms of detection time, the ASVM was found to be the best performing scheme. Regarding our test for detection rate, false positive and false negative, the XCM, ASVM and CDLM performed the same. The results of the XCM were therefore the best and superior to the ASVM and CDLM. This can be attributed to the fact that the XCM scheme is optimised for DDoS and PUE attacks. We can therefore conclude that our XCM scheme is the best performing scheme compared to the ASVM and CDLN schemes.

Ubiquitous computing is already weaving itself around us and it is connecting everything to the network of networks. This interconnection of objects to the internet is new computing paradigm called the Internet of Things (IoT) networks. Many capacity and non-capacity constrained devices, such as sensors are connecting to the Internet. These devices interact with each other through the network and provide a new experience to its users. In order to make full use of this ubiquitous paradigm, security on IoT is important. There are problems with privacy concerns regarding certain algorithms that are on IoT, particularly in the area that relates to their avalanche effect means that a small change in the plaintext or key should create a significant change in the ciphertext. The higher the significant change, the higher the security if that algorithm. If the avalanche effect of an algorithm is less than 50% then that algorithm is weak and can create security undesirability in any network. In this, case IoT. In this study, we propose to do the following: (1) Search and select existing block cryptographic algorithms (maximum of ten) used for authentication and encryption from different devices used on IoT. (2) Analyse the avalanche effect of select cryptographic algorithms and determine if they give efficient authentication on IoT. (3) Improve their avalanche effect by designing a mathematical model that improves their robustness against attacks. This is done through the usage of the initial vector XORed with plaintext and final vector XORed with cipher tect. (4) Test the new mathematical model for any enhancement on the avalanche effect of each algorithm as stated in the preceding sentences. (5) Propose future work on how to enhance security on IoT. Results show that when using the proposed method with variation of key, the avalanche effect significantly improved for seven out of ten algorithms. This means that we have managed to improve 70% of algorithms tested. Therefore indicating a substantial success rate for the proposed method as far as the avalanche effect is concerned. We propose that the seven algorithms be replaced by our improved versions in each of their implementation on IoT whenever the plaintext is varied. / Electrical and Mining Engineering / M. Tech. (Electrical Engineering)

Particle Swam Optimization (PSO) is especially useful for rapid optimization of problems involving multiple objectives and constraints in dynamic environments. It regularly and substantially outperforms other algorithms in benchmark tests. This paper describes research leading to the application of PSO to the autonomous asset management problem in electronic warfare. The PSO speed provides fast optimization of frequency allocations for receivers and jammers in highly complex and dynamic environments. The key contribution is the simultaneous optimization of the frequency allocations, signal priority, signal strength, and the spatial locations of the assets. The fitness function takes into account the assets' locations in 2 dimensions, maximizing their spatial distribution while maintaining allocations based on signal priority and power. The fast speed of the optimization enables rapid responses to changing conditions in these complex signal environments, which can have real-time battlefield impact. Results optimizing receiver frequencies and locations in 2 dimensions have been successful. Current run-times are between 450ms (3 receivers, 30 transmitters) and 1100ms (7 receivers, 50 transmitters) on a single-threaded x86 based PC. Run-times can be substantially decreased by an order of magnitude when smaller swarm populations and smart swarm termination methods are used, however a trade off exists between run-time and repeatability of solutions. The results of the research on the PSO parameters and fitness function for this problem are demonstrated.

A malicious actor often relies on security vulnerabilities of IT systems to launch a cyber attack. Most cloud services are supported by an orchestration of large and complex systems which are prone to vulnerabilities, making threat assessment very challenging. In this research, I developed formal and practical ontology-based techniques that enable automated evaluation of a cloud system's security threats. I use an architecture for threat assessment of cloud systems that leverages a dynamically generated ontology knowledge base. I created an ontology model and represented the components of a cloud system. These ontologies are designed for a set of domains that covers some cloud's aspects and information technology products' cyber threat data. The inputs to our architecture are the configurations of cloud assets and components specification (which encompass the desired assessment procedures) and the outputs are actionable threat assessment results. The focus of this work is on ways of enumerating, assessing, and mitigating emerging cyber security threats. A research toolkit system has been developed to evaluate our architecture. We expect our techniques to be leveraged by any cloud provider or consumer in closing the gap of identifying and remediating known or impending security threats facing their cloud's assets.

Resilient networks have the ability to provide the desired level of service, despite challenges such as malicious attacks and misconfigurations. The primary goal of this dissertation is to be able to provide uninterrupted network services in the face of an attack or any failures. This dissertation attempts to apply control system theory techniques with a focus on system identification and closed-loop feedback control. It explores the benefits of system identification technique in designing and validating the model for the complex and dynamic networks. Further, this dissertation focuses on designing robust feedback control mechanisms that are both scalable and effective in real-time. It focuses on employing dynamic and predictive control approaches to reduce the impact of an attack on network services. The closed-loop feedback control mechanisms tackle this issue by degrading the network services gracefully to an acceptable level and then stabilizing the network in real-time (less than 50 seconds). Employing these feedback mechanisms also provide the ability to automatically configure the settings such that the QoS metrics of the network is consistent with those specified in the service level agreements.

Research accentuates that end-users‘ noncompliance with information security policy (ISP) is a key concern for government just as it is for the private sector. Although awareness and training programmes are important factors impacting employees‘ intentions to comply with an organisation‘s ISP, it can be argued that there is insufficient empirical evidence to support this assertion. To address this gap, this study seeks to expand research on ISP compliance by focusing on attitudes as targets of change. A research model based on the Theory of Planned Behaviour was proposed to illustrate the influence of ISP awareness training on end-users‘ attitudes towards complying with their organisation‘s ISP. Relevant hypotheses were developed to test the research conceptualisation. A survey and an experiment was undertaken to collect the data from a sample of 173 end-users of a single government organisation in one province. The data was captured and analysed using a Statistical Package for Social Sciences (SPSS). Furthermore, Structural Equation Modelling (SEM) was used to test whether the overall model appears to be a good fit to support the hypotheses. The reliability, validity, and model fit were found to be statistically significant, and three out of five research hypotheses were supported. Overall this study contributes to the existing body of knowledge by providing an understanding of the methods that can be used to encourage end-users‘ ISP compliance behaviour through an attitudinal shift, thereby targeting end-users‘ attitude as a means to improve information security policy compliance. Implications of the findings are further discussed in the paper. / Information Technology / M. Tech. (Information Technology)

The mobility attribute of a mobile agent implies deployment thereof in untrustworthy environments, which introduces malicious host threats. The research question deals with how a security framework could be constructed to address the mentioned threats without introducing high costs or restraining the mobile agent's autonomy or performance. Available literature have been studied, analysed and discussed. The salient characteristics as well as the drawbacks of current solutions were isolated. Through this knowledge a dynamic mobile agent security framework was defined. The framework is based on the definition of multiple security levels, depending on type of deployment environment and type of application. A prototype was constructed and tested and it was found to be lightweight and efficient, giving developers insight into possible security threats as well as tools for maximum protection against malicious hosts. The framework outperformed other frameworks / models as it provides dynamic solutions without burdening a system with unnecessary security gadgets and hence paying for it in system cost and performance / Computing / D.Phil.

Nearly all present-day commercial intrusion detection systems are based on a hierarchical architecture. In such an architecture, the root node is responsible for detecting intrusions and for issuing responses. However, an intrusion detection system (IDS) based on a hierarchical architecture has many single points of failure. For example, by disabling the root node, the intrusion-detection function of the IDS will also be disabled. To solve this problem, an IDS inspired by the human immune system is proposed. The proposed IDS has no single component that is responsible for detecting intrusions. Instead, the intrusion-detection function is divided and placed within mobile agents. Mobile agents act similarly to white blood cells of the human immune system and travel from host to host in the network to detect intrusions. The IDS is fault-tolerant because it can continue to detect intrusions even when most of its components have been disabled. / Computer Science (School of Computing) / M. Sc. (Computer Science)

The availability of numerous mobile agent systems with its own strengths and weaknesses poses a problem when deciding on a particular mobile agent system. In this dissertation, factors based on mobility, communication and security of the mobile agent systems are presented and used as a means to address this problem. To facilitate in the process of selection, a grouping scheme of the agent system was proposed. Based on this grouping scheme, mobile agent systems with common properties are grouped together and analyzed against the above-mentioned factors. In addition, an application was developed using the Aglet Software Development Toolkit to demonstrate certain features of agent mobility, communication and security. / Theoretical Computing / M. Sc. (Computer Science)

Threats to computerised information systems are always on the rise and compel organisations to invest a lot of money and time amongst other technical controls in an attempt to protect their critical information from inherent security risks. The computerisation of information systems in secondary schools has effectively exposed these organisations to a host of complex information security challenges that they have to deal with in addition to their core business of teaching and learning. Secondary schools handle large volumes of sensitive information pertaining to educators, learners, creditors and financial records that they are obliged to secure. Computerised information systems are vulnerable to both internal and external threats but ease of access sometimes manifest in security breaches, thereby undermining information security. Unfortunately, school managers and users of computerised information systems are ignorant of the risks to their information systems assets and the consequences of the compromises that might occur thereof. One way of educating school managers and users about the risks to their computerised information systems is through a risk management programme in which they actively participate. However, secondary schools do not have the full capacity to perform information security risk management exercises due to the unavailability of risk management experts and scarce financial resources to fund such programmes. This qualitative case study was conducted in two secondary schools that use computerised information systems to support everyday administrative operations. The main objective of this research study was to assist secondary schools that used computerised information systems to develop a set of guidelines they would use to effectively manage information security risks in their computerised information systems. This study educated school managers and computerised information systems users on how to conduct simple risk management exercises. The Operationally Critical Threats, Assets and Vulnerability Evaluation for small-scale organisations risk management method was used to evaluate the computerised information systems in the two schools and attain the goals of the research study. Data for this study were generated through participatory observation, physical inspections and interview techniques. Data were presented, analysed and interpreted qualitatively. This study found that learners‟ continuous assessment marks, financial information, educators‟ personal information, custom application software, server-computers and telecommunication equipment used for networking were the critical assets. The main threats to these critical assets were authorised and unauthorised systems users, malware, system crashes, access paths and incompatibilities in software. The risks posed by these threats were normally led to the unavailability of critical information systems assets, compromise of data integrity and confidentiality. This also led to the loss of productivity and finance, and damage to school reputation. The only form of protection mechanism enforced by secondary schools was physical security. To mitigate the pending risks, the study educated school managers and users in selecting, devising and implementing simple protection and mitigation strategies commensurate with their information systems, financial capabilities and their level of skills. This study also recommended that secondary schools remove all critical computers from open-flow school networks, encrypt all critical information, password-protect all computers holding critical information and train all users of information systems of personal security. The study will be instrumental in educating school managers and computerised information systems users in information security awareness and risk management in general. / Science Engineering and Technology / M.Sc. (Information Systems)