Nesta tese investigam-se três pontos ligados a fragilidades topológicas de grafos e suas aplicações a redes complexas reais e, em especial, a redes de relacionamentos criminais. Na primeira etapa, apresenta-se in abstracto um método inédito e eficiente de fragmentação de redes complexas por módulos. O procedimento identifica em primeiro lugar comunidades topológicas por meio da qual a rede pode ser representada usando algoritmos heurísticos de extração de comunidades. Então, somente os nós que participam de ligaçõees inter-comunitaárias são removidos em ordem decrescente de sua centralidade de intermediação. Ilustra-se o método pela aplicação a uma variedade de redes reais nas áreas social, de infraestrutura, e biológica. Mostra-se que a abordagem por módulos supera ataques direcionados a vértices baseados somente no ordenamento de índices de centralidade, com ganhos de eficiência fortemente relacionados à modularidade da rede.No segundo momento, introduzem-se os conceitos de robustez e fragilidade de redes generalizadas para avaliar o quanto um determinado sistema se comporta frente a ataques incompletos. Ainda, avalia-se o desempenho (relação entre robustez e custo computacional) de diversos ataques sequenciais e simultâneos a redes modulares por meio de uma medida empírica que chamamos de performance. Mostra-se por meio de redes artificiais de referência e de redes reais que para sistemas altamente modulares a estratégia de fragmentação por módulos apresenta um desempenho até 10 vezes superior aos demais ataques. Na última etapa, explora-se com maior profundidade a natureza subjacente de redes reais de relacionamentos criminais. Apresenta-se uma rede única e sem precedentes construída pela Polícia Federal Brasileira consistindo de mais de 35.000 relacionamentos entre 24.000 indivíduos. Os dados foram coletados entre abril e agosto de 2013 e consistem em informações fornecidas diretamente pelos investigadores responsáveis de cada caso. O sistema apresenta características típicas de redes sociais, porém é bem mais “escuro"que o comportamento típico, com baixos níveis tanto de densidade de arestas quanto de eficiência de rede. Além do mais, o sistema é extremamente modular o que implica ser possível desmantelar toda a rede de crimes federais brasileiros com a remoção de aproximadamente 2% dos indivíduos escolhidos conforme a prescrição do método modular. Também, a rede é controlável no sentido da teoria matemática de controle, significando que com acesso a aproximadamente 20% dos nós é possível, em tese, levar qualquer variável dinâmica de um estado inicial a um estado final arbitrário em um tempo finito. Exibi-se tambám uma análise topológica e de fragilidades de uma segunda rede criminal relacionada a investigações da Polícia Federal. Trata-se de um fórum online destinado à prática de crimes cibernéticos na chamada camada profunda da internet (deep web). (Continuação ) Após a coleta dos dados foi possível construir uma rede de relacionamentos com quase 10.000 indivíduos. Comparou-se, entãoo, a estratégia usada de fato pela Polícia Federal durante a Operação Darknet com a previsão teórica de ataques topológicos à rede criminal e mostrou-se que ataques dirigidos por grau teriam fragmentado o sistema de maneira quase 15 vezes mais eficiente. Por outro lado, esta rede não é modular apesar de novamente apresentar uma arquitetura mais “escura" que o usual. Por termo, demonstra-se que os ataques por arestas estão diretamente relacionados ao aprisionamento enquanto que a ressocialização e/ou morte dos indivíduos é melhor interpretada como a remoção por vértices. Destarte, comprovou-se que de um ponto de vista topológico a ressocialização é de fato mais eficiente em reduzir a criminalidade do que o aprisionamento. Contudo, na rede de crimes federais estudada essa diferenca é muito pequena, de tal modo que ambas as políticas poderiam, em tese, ser aplicadas a fim de se combater eficientemente o sistema criminoso. / In this thesis we investigate three points connected to topological fragilities of graphs and their applications to real complex networks and, in particular, to networks of criminal relationships. In the first step, we present an unprecedented and efficient method of fragmentation of complex networks by modules. Firstly, the procedure identifies topological communities through which the network can be represented using heuristic communities extraction algorithms. After that, only the nodes that bridge communities are removed in descending order of their betweenness centrality . We illustrate the method by the applying it to a variety of real networks in the social, infrastructure, and biological fields. We show that the modular approach outperforms attacks traditional attacks based only on the ordering of centrality indexes, with efficiency gains strongly related to the modularity of the network. In the second moment, we introduce the concepts of generalized robustness and fragility of networks to evaluate how much a certain system behaves in the face of incomplete attacks. Also, we evaluate the relation between robustness and computational cost of several sequential and simultaneous attacks to modular networks by means of an empirical measure that we call performance. In this sense, we show through artificial and real networks that for highly modular systems the strategy of fragmentation by modules presents a performance up to 10 times superior to traditional attacks. In the last step, we explore in more depth the underlying nature of real networks of criminal relationships. We present a unique and unprecedented network built by the Brazilian Federal Police consisting of more than 35,000 relationships among 24,000 individuals. The data were collected between April and August 2013 and consist of information provided directly by the investigators responsible for each case. The system has typical characteristics of social networks, but is much "darker"than traditional social networks, with low levels of edge density and network efficiency. Moreover, the network is extremely modular which implies that it is possible to dismantle all the network of Brazilian federal crimes with the removal of approximately 2% of the individuals chosen according to the modular method. Also the network is controllable in the sense of the mathematical control theory, meaning that with access only to 20% of nodes it is possible, In theory, to take any dynamic variable from an initial state to an arbitrary final state in a finite time. We also show a topological analysis of a second criminal network related to Federal Police investigations. This is an online forum for cybercrime in the so-called deep web. After the data collection, it was possible to build a network of relationships with almost 10,000 individuals. We then compared the strategy actually used by the Federal Police during Operation Darknet with the theoretical prediction of topological attacks on the criminal network and showed that degree-based attacks would have fragmented the system almost 15 times more efficiently. On the other hand, this network is not modular despite presenting a "darker"architecture than usual. As a last result, this particular system is not controllable in practical terms. We finish the study by showing that edge attacks are directly related to the imprisonment whereas the resocialization and/or death of the individuals is better interpreted as the removal of vertices. Thus, we prove that from a topological point of view resocialization is in fact more efficient in reducing crime rates than imprisonment. However, in the network of federal crimes studied here this difference is very small, so that both policies could in theory be applied in order to combat effectively the criminal system.

Cloud computing is the computing model in which the computing resources such as software, hardware and data are delivered as a service through a web browser or light-weight desktop machine over the internet (Wink, 2012). This computing model abolishes the necessity of sustaining the computer resources locally hence cuts-off the cost of valuable resources (Moreno, Montero & Llorente, 2012). A distinctive cloud is affected by different security issues such as Temporary Denial of Service (TDOS) attacks, user identity theft, session hijacking issues and flashing attacks (Danish, 2011). The purpose of this study is to bridge the research gap between the cloud security measures and the existing security threats. An investigation into the existing cloud service models, security standards, currently adopted security measures and their degree of flawless protection has been done. The theoretical study helped in revealing the security issues and their solutions whereas the empirical study facilitated in acknowledging the concerns of users and security analysts in regards to those solution strategies. The empirical methods used in this research were interviews and questionnaires to validate the theoretical findings and to grasp the innovativeness of practitioners dealing with cloud security.With the help of theoretical and empirical research, the two-factor mechanism is proposed that can rule out the possibility of flashing attacks from remote location and can help in making the cloud components safer. The problem of junk traffic can be solved by configuring the routers to block junk data packets and extraneous queries at the cloud outer-border. This security measure is highly beneficial to cloud security because it offers a security mechanism at the outer boundary of a cloud. It was evaluated that a DOS attack can become a huge dilemma if it affects the routers and the effective isolation of router-to-router traffic will certainly diminish the threat of a DOS attack to routers. It is revealed that the data packets that require a session state on the cloud server should be treated separately and with extra security measures because the conventional security measures cannot perform an in-depth analysis of every data packet. This problem can be solved by setting an extra bit in the IP header of those packets that require a state and have a session. Although this change should be done at universal level and would take time; it can provide a protocol-independent way to identify packets which require extra care. It will also assist firewalls to drop bits which are requesting a session sate without a state-bit being set. The cloud security analysts should consider that the interface and authentication layer should not be merged into a single layer because it endangers the authentication system as the interface is already exposed to the world. The use of login-aiding devices along with secret keys can help in protecting the cloud users. Moreover, a new cloud service model “Dedicated cloud” is proposed in this research work to reinforce the cloud security. It was discovered that the optimal blend of HTTPS and SSL protocols can resolve the problem of session hijacks. The client interface area should be protected by HTTPS protocols and the secure cookies should be sent through a SSL link along with regular cookies. Disallowing the multiple sessions and the use of trusted IP address lists will help even further. A reasonable amount of care has been paid to ensure clarity, validity and trustworthiness in the research work to present a verifiable scientific knowledge in a more reader-friendly manner. These security guidelines will enhance the cloud security and make a cloud more responsive to security threats. / Program: Masterutbildning i Informatik

Wireless spectrum is a limited resource that must be used efficiently. It is also a broadcast medium, hence, additional procedures are required to maintain communication over the wireless spectrum private. In this thesis, we investigate three key issues related to efficient use and privacy of wireless spectrum use. First, we propose GAVEL, a truthful short-term auction mechanism that enables efficient use of the wireless spectrum through the licensed shared access model. Second, we propose CPRecycle, an improved Orthogonal Frequency Division Multiplexing (OFDM) receiver that retrieves useful information from the cyclic prefix for interference mitigation thus improving spectral efficiency. Third and finally, we propose WiFi Glass, an attack vector on home WiFi networks to infer private information about home occupants. First we consider, spectrum auctions. Existing short-term spectrum auctions do not satisfy all the features required for a heterogeneous spectrum market. We discover that this is due to the underlying auction format, the sealed bid auction. We propose GAVEL, a truthful auction mechanism, that is based on the ascending bid auction format, that avoids the pitfalls of existing auction mechanisms that are based on the sealed bid auction format. Using extensive simulations we observe that GAVEL can achieve better performance than existing mechanisms. Second, we study the use of cyclic prefix in Orthogonal Frequency Division Multiplexing. The cyclic prefix does contain useful information in the presence of interference. We discover that while the signal of interest is redundant in the cyclic prefix, the interference component varies significantly. We use this insight to design CPRecycle, an improved OFDM receiver that is capable of using the information in the cyclic prefix to mitigate various types of interference. It improves spectral efficiency by decoding packets in the presence of interference. CPRecycle require changes to the OFDM receiver and can be deployed in most networks today. Finally, home WiFi networks are considered private when encryption is enabled using WPA2. However, experiments conducted in real homes, show that the wireless activity on the home network can be used to infer occupancy and activity states such as sleeping and watching television. With this insight, we propose WiFi Glass, an attack vector that can be used to infer occupancy and activity states (limited to three activity classes), using only the passively sniffed WiFi signal from the home environment. Evaluation with real data shows that in most of the cases, only about 15 minutes of sniffed WiFi signal is required to infer private information, highlighting the need for countermeasures.

Le développement du transport partout dans le monde a fourni un grand nombre d'avantages pour de nombreux aspects de la vie humaine. Les systèmes de transport intelligents (ITS) sont des applications avancées qui visent à rendre les réseaux de transport plus sûrs, plus pratiques et plus intelligents. Selon leurs usages, ils peuvent être classés en deux types d'applications ITS, qui sont des applications de sûreté et des applications non-sûreté. Le réseau de véhicules ad hoc (VANET) est un élément clé des systèmes ITS, car il permet la communication entre les unités de transport. Ces communications prennent en charge différentes applications ITS avec différentes propriétés. Parmi les deux types d'applications, nous nous intéressons aux applications de sûreté qui ont des contraintes de qualité de service et des contraintes de sécurité plus strictes. Selon le scénario considéré et l'application de sûreté donnée, les informations échangées entre les véhicules doivent être diffusé localement dans une communication à un seul saut et / ou également notifiées aux véhicules à large dimension. L'objectif principal de cette thèse est d'améliorer les performances des applications de sûreté en termes de qualité de service et de sécurité, à la fois dans une communication à un saut et dans une communication multi-sauts. Nous nous intéressons à la fiabilité, la connectivité et le déni de service (DoS). Nous étudions et proposons des solutions techniques provenant de couches inférieures (Physique, Liaison et Réseaux) qui jouent un rôle fondamental dans l'atténuation des défis créés par la nature de l'environnement des véhicules. Tout d'abord, nous introduisons une nouvelle méthode efficace pour fiabiliser la radiodiffusion. Dans notre système, les messages de sécurité sont rediffusés lorsque l'expéditeur est sollicité. Cela augmente le pourcentage de véhicules qui reçoivent les messages alors que le nombre de messages dupliqués reste limité. En second lieu, en tenant compte de la fragmentation du réseau, nous étudions des solutions qui permettent de pallier la déconnexion temporaire du réseau pour apporter l'information de sécurité aux destinataires. Basé sur les propriétés sociales des réseaux de véhicules, nous proposons un protocole de transfert basé sur des relations sociales pour relayer la communication entre les véhicules et des points d'intérêt qui fournissent des services de sécurité avec des contraintes de temps plus souples, telles que la recherche et le sauvetage. Troisièmement, nous étudions l'attaque de brouillage, une sorte d'attaques DoS, qui est cruciale pour les applications de sûreté et qui et facilement réalisable au niveau des couches inférieures. Nous modélisons l'attaque de brouillage afin d'étudier la dégradation causée par l'attaque sur les performances du réseau. La dégradation à un certain niveau dans les performances du réseau est une indication de présence d'attaques de brouillage dans le réseau; donc les résultats de cette analyse nous permettent de déterminer les seuils de performance du réseau pour distinguer entre les scénarios normaux et les scénarios attaqués. Toutefois, selon cette analyse, le procédé utilisant la dégradation comme une indication pour détecter une attaque de brouillage est impossible pour des applications temps réel. Par conséquent, nous proposons des nouvelles méthodes afin de détecter les attaques de brouillage temps réel. Nos méthodes permettent la détection en temps réel avec une grande précision, non seulement chez le moniteur central mais aussi au niveau de chaque véhicule. Par conséquent, les véhicules sont avertis sur l'attaque assez tôt pour récupérer la communication et réagir à ces attaques. / The development of transportation all over the world has been providing a lot of benefits for many aspects of human life. Intelligent Transportation Systems (ITS) are advanced applications that aim to make the transport networks safer, more convenient and smarter. According to their usages, they can be classified into two types of ITS applications, which are safety applications and non-safety applications. Vehicular ad hoc network (VANET) is a key component of ITS since it enables communications among transportation units. These communications support different ITS applications with various properties. Between two types of applications, we are interested in safety applications which have tighter quality and security constraints. Depending on an applied scenario of a given safety application, the exchanged information among vehicles must be broadcast locally within one-hop communication and/or also be notified to vehicles in large range. The main objective of this thesis is to improve the performance of safety applications in term of the quality of service and security, in both one-hop communication and multi-hop communication. We focus on reliability, connectivity and Denial of Services (DoS) attack. We study and propose technical solutions coming from lower layers (Physical, MAC and network layers) which play a fundamental role in mitigation to challenges created by the nature of the vehicular environment. Firstly, we introduce a reliable scheme to achieve the reliability for broadcasting. In our scheme, the safety messages are rebroadcast when the sender is solicited. This increases the percentage of vehicles receiving the messages while duplicated messages are limited. Secondly, with consideration of the fragmentation of the network, we study solutions that overcome the temporary disconnection in the network to bring the safety information to the recipients. Based on the social properties of vehicular networks, we propose a social-based forwarding protocol to support the communication between vehicles to points of interest that provide safety services with looser time constraints, such as search and rescue. Thirdly, we investigate jamming attack, a kind of DoS attacks, which is crucial for safety applications because of the adequate condition of the attack at the lower layers. We model jamming attack on broadcasting in order to study the degradation caused by the attack on network performance. The degradation at a certain level in network performance is an indication of a jamming attack presence in the network; therefore results from this analysis will allow us to determine network performance thresholds to distinguish between normal and attacked scenarios. However, according to our analysis, the method using the degradation as an indication to detect a jamming attack is not feasible for real-time applications. Hence, we propose methods to detect jamming attacks in real-time. Our methods allow real-time detection with high accuracy, not only at the central monitor but also at each vehicle. Therefore, vehicles are noticed about the attack soon enough to recover the communication and react to these attacks.

Canais seguros, como os gerados pelos protocolos SSL e TLS, são cada vez mais utilizados nos serviços de rede para propiciar autenticação de parceiro, integridade e sigilo dos dados. Porém, sua utilização impede que um sistema de detecção de intrusão de rede possa observar o conteúdo dos pacotes, impossibilitando a análise das mensagens. Como alternativa de contorno deste problema é proposta a arquitetura de um agente de detecção, prevenção e contenção de ataques baseado em aplicação, que possibilite interceptar fluxos de mensagens diretamente na aplicação, inserido no contexto de uma arquitetura de detecção distribuída e padronizada. O ADACA (Agente de Detecção, Análise e Contenção de Ataques) é um agente IDS (Intrusion Detection System) híbrido capaz de operar tanto no modo ativo quanto passivo. Dessa forma, permite realizar a análise do conteúdo de mensagens que estejam protegidos por protocolos seguros, como o SSL e TLS, e adotar uma medida predefinida antes que a aplicação alvo processe um conteúdo malicioso. Além disso, o padrão de formato de mensagens de alertas IDMEF (Intrusion Detection Message Exchange Format), proposto pelo IDWG, é adotado para notificação de eventos do agente ADACA a um IDS central. Os resultados obtidos mostraram a viabilidade da utilização de agentes de aplicação, acoplados diretamente à aplicação, como complemento aos sistemas IDS de rede. / Secure channel, as the one generated by protocols like SSL and TLS, has been used on network services to provide partner authentication, integrity and confidentiality. However, its utilization prevents a network intrusion detection system to observe and analyze packets content. As an alternative to circumvent this problem, the present work proposes an agent-based intrusion detection, prevention and containment architecture capable to capture messages flows directly at the host application and introduce it on a distributed intrusion detection framework. The ADACA (Attack Detection, Analysis and Containment Agent) is a hybrid agent that can operate on active and passive mode. In this context, it is able to detect attacks where the application payload is encrypted by secure protocols, like SSL and TLS, and take some predefined measure before the host application process a malicious content. Further that, Intrusion Detection Message Exchange Format (IDMEF) standard proposed by IDWG is considered to send alerts between agent ADACA and an IDS central. The results shown that is practicable to use an application agent attached to an application as a complement of network intrusion detection systems.

Thesis ( M.Sc. ( Computer Science)) -- University of Limpopo, 2018 / Dynamic spectrum access enabled by cognitive radio networks is envisioned to address the problems of the ever-increasing wireless technology. This innovative technology increases spectrum utility by allowing unlicensed devices to utilise the unused spectrum band of licenced devices opportunistically. The unlicensed devices referred to as secondary users (SUs) constantly sense the spectrum band to avoid interfering with the transmission of the licenced devices known as primary users (PUs).Due to some environmental challenges that can interfere with effective spectrum sensing, the SUs have to cooperate in sensing the spectrum band. However, cooperative spectrum sensing is susceptible to the spectrum sensing data falsification (SSDF) attack where selfish radios falsify the spectrum reports. Hence, there is a need to design a defence scheme that will defend the SSDF attack and guaranty correct final transmission decision. In this study, we proposed the integration of the reputation based system and the qout-of-m rule scheme to defend against the SSDF attack. The reputation-based system was used to determine the trustworthiness of the SUs. The q-out-of-m rule scheme where m sensing reports were selected from the ones with good reputation and q was the final decision, which was used to isolate the entire malicious nodes and make the correct final transmission decision. The proposed scheme was implemented in a Cognitive Radio Ad Hoc Network (CRAHN) where the services of a data fusion centre (FC) were not required. The SUs conducted their own data fusion and made their own final transmission decision based on their sensing reports and the sensing reports of their neighbouring nodes. Matlab was used to implement and simulate the proposed scheme. We compared our proposed scheme with the multifusion based distributed spectrum sensing and density based system schemes. Metrics used were the success probability, missed detection probability and false alarm probability. The proposed scheme performed better compared to the other schemes in all the metrics. / CSIR, NRF and, University of Limpopo research office

Leaders bring unconscious information into their personal and working relationships. Some of this unconscious material is communicated through language use, and it is argued that one of the bridges between the unconscious and the conscious is language use. It is postulated that insight is possible into leaders’ understanding, meaning-making and leadership experience by exploring their language use, as the vehicle through which they make sense of the world. Hence, the aim of this study was to explore by developing and describing a systems psychodynamic model of language use as manifestation of leadership anxiety dynamics, to refine this theoretical model, and to explore the utility value of the theoretical model. A qualitative and descriptive research method was selected towards reaching this aim. Hermeneutic phenomenology, using the systems psychodynamic perspective allowed for the description, analysis and interpretation of the experiences of participants. Data was collected through a purposive, convenient sample, in the form of three listening posts, which comprised systems psychodynamic practitioners, business leaders and post-modern discourse analysts. Data was analysed by means of critical discourse analysis and systems psychodynamically informed discourse analysis. Manifesting themes were the language of titles, as potential space, and the language of silence versus non-silence; anxiety and its triggers, anxiety and leadership response, and anxiety and language use; the sources of anxiety, language as unconscious defence and offence and towards a language of vulnerability. The findings indicated that leaders use both conscious and unconscious expressions of language simultaneously. Language use manifested as the carrier of conscious messages (between sender and receiver) as well as the unconscious role of language, to attack (accessing the dark side of language use) or defend against anxieties, and to cover leadership vulnerabilities. Language use as container, as well as transitional phenomenon (a potential space) is a carrier of anxieties. Language use thus has the potential to be used for its defensive, regressive and relational value. In a world of uncertainty and increasing attack on and by leadership, the findings further indicated that the defended leaders should be aware of the conscious and unconscious impact and outcome of language. Language use is useful as a lens to explore, diagnose and raise awareness, because the unconscious reveals itself through language as speech and image, and through the language of relations and relatedness and the language of action and omission. Since leaders operate in a colliquated space, both at individual and systemic level (i.e. as collisions), leadership anxiety could be elevated, resulting in the access of the dark side of language use. However, when these collisions occur, leadership anxiety could be reduced when the leader enters the reflective or potential space by accessing the relational value of language use. The utility value of the systems psychodynamic model was subsequently also confirmed. / Industrial and Organisational Psychology / D. Com. (Industrial and Organisational Psychology)

'Snap Shot' is a Young Adult novel centred around two main characters – 16 year-old Bel and her older step-sister, Diane, who was living in New York on September 11, 2001. The novel begins with a bus crash on a city freeway, and the narrator, who we later learn is Bel, unfolds the story that leads up to the crash. There are many plotlines that run through the novel, narrated in a variety of voices by Bel. She tells the story of her step-sister, who witnessed the September 11 attack from a distance (in Queens). She reveals her sister's story in the weeks following the attack. Diane is inspired by the image of one of the victims of the attack, a woman named Sena. She sees her photo in one of the desperate fliers that popped up around the city after the attack, and recognises a bracelet the woman is wearing as similar to one owned by her mother. Diane acts on an impulsive idea to somehow bring redemption to the family of this woman by creating a false photograph of the bracelet at Ground Zero, but she is detained by the National Guard. This is an incident that leads to her mother's decision to return to Australia to live. Back in Australia, Diane makes contact with her father, who is distant and dishonest with her. Diane asks to see her younger step-sister, Bel, but she is met with strong resistance. It is obvious that she is being kept from her sister. Bel also learns that her step-sister is back, but her attempts to make contact are blocked by her parents. Eventually the two sisters get together, and the younger forms a fascination and powerful admiration for her older sister, who is now a photographer. She takes images of men she has never met and posts them on her website with emotive labels such as 'victim' or 'terrorist'. Bel's fascination with her older sister leads her to want to emulate her. She sets out to take a photograph of a stranger, and stalks a young man for two days, working up the courage to approach him and interact with him. The fact that she wants to interact with her subject creates tension with her sister, who never speaks with her subjects. They argue about Bel's safety and Diane's courage. Bel eventually approaches the young man, Robert, and forms a connection with him. The coming together of these three characters sets in motion an idea, impulsive and provocative, driven by Bel, to create an artificial moment of terror on a bus as a means to shock the passengers and shake them from a 'dream'. This story is told through counter-voices that offer harmony and dissonance, and at times perspective, to the unfolding plotline. There is Shahrazade, an evocation of Bel's imagination, who is the ultimate in the courageous storyteller. Shahrazade uses narrative to divert her audience away from murderous revenge and into empathic connection. There are the short passages depicting the moments in the bus from the points of view of several passengers. There are the chapters where Bel is interrogated by two police officers, who slowly slide from being realistic characters to figments of Bel's overactive imagination. At the beginning of the novel, Bel tells the reader, 'You are witness to a tragedy, but you don’t call it that.' (Bone 2008) By the end, the verdict is left open. Are the three guilty of creating terror on the bus? Was it a tragedy? Is there redemption in the act of telling a story? The exegetical component of this thesis explores the social, literary and political context of the writing of 'Snap Shot'. It is in three parts, predicated on my research enquiry about the nature of the world we now live in post-September 11, a day that was supposed to have changed history. I explore whether there is a consistent and unified narrative that, as members of the public, we are engaging with. I look at the use of fear by the terrorists, and explore how this fear has manifested itself post-September 11. I ask whether there is an ongoing narrative of fear, and if so, what is its nature? How is it perpetuated? How does the public engage with this narrative? And what implications does this have for the writing of 'Snap Shot'? I explore literary and artistic responses to September 11, and explore the role of the artist as provocateur. What are the taboos and sore points that provocative art can touch on when looking at the subject of the world that has emerged post-September 11? The exegesis also explores how fear and terror are communicated, with a particular reference to symbolism and frames. What imaginings emerged from the subterranean consciousness prior to September 11, and what imaginings are at play today? Significantly, I explore what implications this imagination has for communicating an anti-terrorism message within the context of writing 'Snap Shot'. / Thesis (Ph.D.) - University of Adelaide, School of Humanities, 2008

In this thesis, we present a novel, elegant and simple method for secure transaction authentication and non-repudiation for trading multimedia content. Multimedia content can be video, images, text documents, music, or any form of digital signal, however here we will focus particular on still images with application to video. We will provide proof that not only can receiving parties within a transaction be untrustworthy, but the owner, or members within an owning party, also cannot be trusted. Known as the insider attack, this attack is particularly prevalent in multimedia transactions. Thus the focus of the thesis is on the prevention of piracy, with particular emphasis on the case where the owner of a document is assumed to be capable of deceit, placing the system under the assumption of mutual distrust. We will introduce a concept called staining, which will be used to achieve authentication and non-repudiation. Staining is composed of two key components: (1) public-key cryptography; and (2) steganographic watermarking. The idea is to watermark a multimedia document after encryption, thereby introducing a stain on the watermark. This stain is due to the non-commutative nature of the scheme, so that decryption will be imperfect, leaving a residue of the cryptographic process upon the watermark. Essentially, secrets from the owner (the watermark) and the receiver (the cryptographic key) are entangled rather than shared, as in most schemes. We then demonstrate our method using image content and will test several different common cryptographic systems with a spread-spectrum type watermark. Watermarking and cryptography are not usually combined in such a manner, due to several issues such as the rigid nature of cryptography. Contrary to the expectation that there will be severe distortions caused to the original document, we show that such an entanglement is possible without destroying the document under protection. We will then attack the most promising combination of systems by introducing geometric distortions such as rotation and cropping, as well as compressing the marked document, to demonstrate that such a method is robust to typical attacks. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1297339 / Thesis (Ph.D.) - University of Adelaide, School of Electrical and Electronic Engineering, 2007

<p>Recently the society has been turning from the use of paper-based technologies to plastic cards in certain spheres of our life. With the emergence and proliferation of high technologies we cannot content with the security provided bypaper only. Therefore the society has chosen plastic to protect its information because it offers far more security based not only on human perception but also on machine-readable elements. </p><p>The number of plastic cards in circulation in different spheres of our everyday life increases constantly. They replace money, documents and allow easy and safe access to some services. In spite of its security the plastic card however is subjected to fraud. </p><p>Plastic card fraud results in significant losses for the various industries. Since the first appearance of plastic cards methods of committing fraud have changed dramatically. Now there is a wide range of high technologies at the disposal of criminals as well as card manufacturers. </p><p>Therefore we have put the great emphasize of this work on the analysis of the most common card technologies in the Plastic Card World, the magnetic stripe and the chip, existing crimes and main means of their committing. And we also have revealed the weak and strong sides of the prevention techniques, which are currently in use.</p>