Information technology (IT) security, which is concerned with protecting the confidentiality, integrity and availability of information technology assets, inherently possesses a significant amount of known and unknown risks. The need to manage IT security risk is regarded as an important aspect in the daily operations within organisations. IT security risk management has gained considerable attention over the past decade due to the collapse of some large organisations in the world. Previous investigative research in the field of IT security has indicated that despite the efforts that organisations use to reduce IT security risks, the trend of IT security attacks is still increasing. One of the contributing factors to poor management of IT security risk is attributed to the fact that IT security risk management is often left to the technical security technologists who do not necessarily employ formal risk management tools and reasoning. For this reason, organisations find themselves in a position where they do not have the correct approach to identify, assess and treat IT security risks. The IT security discipline is complex in nature and requires specialised skills. Organisations generally struggle to find a combination of IT security and risk management skills in corporate markets. The scarcity of skills leaves organisations with either IT security technologists who do not apply risk management principles to manage IT security risk or risk management specialists who do not understand IT security in order to manage IT security risk. Furthermore, IT is dynamic in nature and introduces new threats and vulnerabilities as it evolves. Taking a look at the development of personal computers over the past 20 years is indicative of how change has been constant in this field, from big desktop computers to small mobile computing devices found today. The requirement to protect IT against threats associated with desktops was far less than the requirement associated with protecting mobile devices. There is pressure for organisations to ensure that they stay abreast with the current technology and associated risks. Failure to understand and manage IT security risk is often cited as a major cause of concern within most organisations’ IT environments because comprehensive approaches to identify, assess and treat IT security risk are not consistently applied. This is due to the fact that the trend of IT security attacks across the globe is on the increase, resulting in gaps when managing IT security risk. Employing a formal risk based approach in managing IT security risk ensures that risks of importance to an organisation are accounted for and receive the correct level of attention. Defining an approach of how IT security risk is managed should be seen as a fundamental task and is the basis of this research. This study aims to contribute to the field of IT security by developing an approach that assists organisations in treating IT security risk more effectively. This is achieved through the use of a combination of existing best practice IT security frameworks and standards principles, basic risk management principles, as well as existing threat modelling processes. The approach developed in this study serves to encourage formal IT security risk management practices within organisations to ensure that IT security risk is accounted for by senior leadership. Furthermore, the approach is anticipated to be more proactive and iterative in nature to ensure that external factors that influence the increasing trend of IT security threats within the IT environment are acknowledged by organisations as technology evolves. / Computing / M. Sc. (Computing)

Les attaques par canaux auxiliaires sont apparues dans la deuxième moitié des années 1990. Ces attaques exploitent différentes informations qu’il est possible de collecter lors de l’exécution d’un algorithme sur un appareil cryptographique. Il est ainsi possible, entre autres, de mesurer la consommation d’énergie d’un appareil cryptographique, ou encore d’observer le temps d’exécution d’un certain algorithme sur un appareil. C’est à ces deux sources d’in- formation que nous nous intéressons dans ce travail. Après une présentation des concepts utiles à la lecture du travail et de l’état de l’art des attaques et des contre-mesures du domaine, nous abordons les résultats de nos recherches effectuées lors de ce travail de thèse. Nous présentons d’abord nos contributions aux attaques par mesure de consommation d’énergie :(1) une approche com- binant apprentissage semi-supervisé et attaques par templates pour retrouver le poids de Hamming des différents bytes d’une clé de chiffrement et (2) une approche utilisant des techniques d’apprentissage automatique pour attaquer une implantation protégée d’AES. Ensuite, nous abordons les contre-mesures investiguées durant nos recherches qui se résument (1) en la possibilité de rendre l’ordre des instructions d’AES le plus aléatoire possible en jouant sur la relation de dépendance entre celles-ci ainsi qu’en (2) l’étude de l’application partielle (sur un sous-ensemble de données) de certaines contre-mesures, afin de protéger les données sensibles d’un algorithme. Enfin, nous terminons ce travail par l’emploi de la programmation orientée aspects comme manière d’implanter des contre-mesures pour les attaques temporelles (sur RSA) et pour les attaques par mesures de consommation d’énergie (sur AES). / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

This study researches the varying threats that emanate from terrorists who carry their activity into the online arena. It examines several elements of this threat, including virtual to virtual attacks and threats to critical infrastructure that can be traced to online sources. It then reports on the methods that terrorists employ in using information technology such as the internet for propaganda and other communication purposes. It discusses how the United States government has responded to these problems, and concludes with recommendations for best practices.