Sécurisation des smart cards par masquage de signal informationnel sur canal secondaire

摘要

Smart Cards are embedded computers making cryptographie operations in order to store confidential data, as money, biometrie information, and access rights management. Thus, it is not surprising that hackers try to intercept them by catching and processing leakages observed on side channel. This thesis aims to design new signal processing techniques for signal hiding used on current consumptions to prevent hackers to perform power analysis attacks. The first introductive chapter makes fall down into Smart Cards world. It allows defining the main objective: to design signal hiding techniques matching with Smart Cards technical requirements. The second chapter présents the study and the statistical characterization of a chaotic dynarnical system, used to pseudo-random numbers génération. From one hand, it will be intensively used in the next chapter, and from the other hand it allows to validate a parallel work leaded by a microelectronic research team. The next chapter présents the signal expansion hiding technique, which consist to swap original signal samples by its Karhunen-loeve expansion coefficients, order 2 uncorrelated. Finally, a last chapter presents another signal hiding technique where thé model used for the observation is parametric. Parameîer is estimatcd following thé maximum likelihood criterion with the help of a new technique based on the couplingof the stochastic matched filtering theory used in détection with the Expcctation-Maximizatïon algorithm. Ail the presented techniques are validated with expérimentations on real signais.