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Security is a primary concern in this era of pervasive computing. Hardware based security mechanisms facilitate the construction of trustworthy secure systems; however, existing hardware security approaches require modifications to the micro-architecture of the processor and such changes are extremely time consuming and expensive to test and implement. Additionally, they incorporate cryptographic security mechanisms that are computationally intensive and account for excessive energy consumption, which significantly degrades the performance of the system. In this dissertation, I explore the domain of hardware based security approaches with an objective to overcome the issues that impede their usability. I have proposed viable solutions to successfully test and implement hardware security mechanisms in real world computing systems. Moreover, with an emphasis on cryptographic memory integrity verification technique and embedded systems as the target application, I have presented energy efficient architectures that considerably reduce the energy consumption of the security mechanisms, thereby improving the performance of the system. The detailed simulation results show that the average energy savings are in the range of 36% to 99% during the memory integrity verification phase, whereas the total power savings of the entire embedded processor are approximately 57%.

The present thesis addresses the MPEG-4 AVC stream watermarking and considers two theoretical and applicative challenges, namely ownership protection and content integrity verification.From the theoretical point of view, the thesis main challenge is to develop a unitary watermarking framework (insertion/detection) able to serve the two above mentioned applications in the compressed domain. From the methodological point of view, the challenge is to instantiate this theoretical framework for serving the targeted applications. The thesis first main contribution consists in building the theoretical framework for the multi symbol watermarking based on quantization index modulation (m-QIM). The insertion rule is analytically designed by extending the binary QIM rule. The detection rule is optimized so as to ensure minimal probability of error under additive white Gaussian noise distributed attacks. It is thus demonstrated that the data payload can be increased by a factor of log2m, for prescribed transparency and additive Gaussian noise power. A data payload of 150 bits per minute, i.e. about 20 times larger than the limit imposed by the DCI standard, is obtained. The thesis second main theoretical contribution consists in specifying a preprocessing MPEG-4 AVC shaping operation which can eliminate the intra-frame drift effect. The drift represents the distortion spread in the compressed stream related to the MPEG encoding paradigm. In this respect, the drift distortion propagation problem in MPEG-4 AVC is algebraically expressed and the corresponding equations system is solved under drift-free constraints. The drift-free shaping results in gain in transparency of 2 dB in PSNR

La présente thèse aborde le sujet de tatouage du flux MPEG-4 AVC sur ses deux volets théoriques et applicatifs en considérant deux domaines applicatifs à savoir la protection du droit d’auteur et la vérification de l'intégrité du contenu. Du point de vue théorique, le principal enjeu est de développer un cadre de tatouage unitaire en mesure de servir les deux applications mentionnées ci-dessus. Du point de vue méthodologique, le défi consiste à instancier ce cadre théorique pour servir les applications visées. La première contribution principale consiste à définir un cadre théorique pour le tatouage multi symboles à base de modulation d’index de quantification (m-QIM). La règle d’insertion QIM a été généralisée du cas binaire au cas multi-symboles et la règle de détection optimale (minimisant la probabilité d’erreur à la détection en condition du bruit blanc, additif et gaussien) a été établie. Il est ainsi démontré que la quantité d’information insérée peut être augmentée par un facteur de log2m tout en gardant les mêmes contraintes de robustesse et de transparence. Une quantité d’information de 150 bits par minutes, soit environ 20 fois plus grande que la limite imposée par la norme DCI est obtenue. La deuxième contribution consiste à spécifier une opération de prétraitement qui permet d’éliminer les impactes du phénomène du drift (propagation de la distorsion) dans le flux compressé MPEG-4 AVC. D’abord, le problème a été formalisé algébriquement en se basant sur les expressions analytiques des opérations d’encodage. Ensuite, le problème a été résolu sous la contrainte de prévention du drift. Une amélioration de la transparence avec des gains de 2 dB en PSNR est obtenue / The present thesis addresses the MPEG-4 AVC stream watermarking and considers two theoretical and applicative challenges, namely ownership protection and content integrity verification.From the theoretical point of view, the thesis main challenge is to develop a unitary watermarking framework (insertion/detection) able to serve the two above mentioned applications in the compressed domain. From the methodological point of view, the challenge is to instantiate this theoretical framework for serving the targeted applications. The thesis first main contribution consists in building the theoretical framework for the multi symbol watermarking based on quantization index modulation (m-QIM). The insertion rule is analytically designed by extending the binary QIM rule. The detection rule is optimized so as to ensure minimal probability of error under additive white Gaussian noise distributed attacks. It is thus demonstrated that the data payload can be increased by a factor of log2m, for prescribed transparency and additive Gaussian noise power. A data payload of 150 bits per minute, i.e. about 20 times larger than the limit imposed by the DCI standard, is obtained. The thesis second main theoretical contribution consists in specifying a preprocessing MPEG-4 AVC shaping operation which can eliminate the intra-frame drift effect. The drift represents the distortion spread in the compressed stream related to the MPEG encoding paradigm. In this respect, the drift distortion propagation problem in MPEG-4 AVC is algebraically expressed and the corresponding equations system is solved under drift-free constraints. The drift-free shaping results in gain in transparency of 2 dB in PSNR

Web systems have become an integral part in daily life of billions of people. Social is a key characteristic today’s web projects need to feature in order to be successful in the social age. To benefit from an improved user experience, individual persons are continually invited to reveal more and more personal data to web systems. With a rising severity of attacks on web systems, it is evident that their security is inadequate for the amount of accumulated personal data. Numerous threat reports indicate that social media has become a top-ranking attack target, with climbing impacts, with ramifications beyond single individuals and with a booming black market to trade leaked personal data. To enhance information security in managing personal data by web systems for the mutual benefit of individual persons, companies and governments, this dissertation proposes a solution architecture and three research contributions. While the solution architecture establishes the foundation for a more secure management of personal data by web systems, the research contributions represent complementary components for protecting personal data against unwanted data disclosure, tampering and use without the actual data owner’s intent or knowledge. Not only do these components enable seamless integration and combination, but they also contribute to assure quality and maintainability. The dissertation concludes with discussing evaluation results and providing an outlook towards future work.

Web systems have become an integral part in daily life of billions of people. Social is a key characteristic today’s web projects need to feature in order to be successful in the social age. To benefit from an improved user experience, individual persons are continually invited to reveal more and more personal data to web systems. With a rising severity of attacks on web systems, it is evident that their security is inadequate for the amount of accumulated personal data. Numerous threat reports indicate that social media has become a top-ranking attack target, with climbing impacts, with ramifications beyond single individuals and with a booming black market to trade leaked personal data. To enhance information security in managing personal data by web systems for the mutual benefit of individual persons, companies and governments, this dissertation proposes a solution architecture and three research contributions. While the solution architecture establishes the foundation for a more secure management of personal data by web systems, the research contributions represent complementary components for protecting personal data against unwanted data disclosure, tampering and use without the actual data owner’s intent or knowledge. Not only do these components enable seamless integration and combination, but they also contribute to assure quality and maintainability. The dissertation concludes with discussing evaluation results and providing an outlook towards future work.