Elliptic curve based cryptosystems are nowadays increasingly used in protocols involving public-key cryptography. This is particularly true in the context of embedded devices whicharesubjecttostrongcost, resources, and efficiencyconstraints, sinceellipticcurve cryptography requires significantly smaller key sizes compared to other cryptosystems such as RSA.
The following study focuses in the first part on secure and efficient implementation of elliptic curve cryptography in embedded devices, especially smart cards. Designing secure implementations requires to take into account physical attacks which can target embedded devices. These attacks include in particular side-channel analysis which may infer information on a secret key manipulated from a component by monitoring how it interacts with its environment, and fault analysis in which an adversary can disturb the normal functioning of a device with the same goal.
In the second part of this thesis, we study these attacks and their impact on the implementation of the most used public-key cryptosystems. In particular, we propose new analysis techniques and new countermeasures for these cryptosystems, together with specific attacks on the AES block cipher.