Classical Fault Attacks often require the ability to encrypt twice the same plaintext, in order to get one or several pairs of correct and faulty cipher texts corresponding to the same message. This observation led some designers to think that a randomized mode of operation may be sufficient to protect block cipher encryption against this kind of threat. In this paper, we consider the case where the adversary neither chooses nor knows the input messages, and has only access to the faulty cipher texts. In this context, we are able to describe several attacks against AES-128 by using non uniform fault models. Our attacks target the last 4 rounds and allow to recover the correct key with practical time complexity, using a limited number of faulty cipher texts. This work highlights the need for dedicated fault attack countermeasures in secure embedded systems.

Recent works show that a combination of perturbation and observation attacks on symmetric ciphers thwarts state-of-the-art countermeasures. In this paper, we first propose a new way - to our knowledge - to classify fault attacks against block ciphers, allowing us to exhibit their capacity to be combined with observation attacks. We then present a set of common protections against side-channel and fault attacks, namely higher-order masking schemes, detection and infection countermeasures, and how they can be combined. We show that the combination of a higher-order masking scheme and a detection countermeasure can actually be defeated by a slight variant of the combined attack of Roche et al., even if one applies their patch. Furthermore, we also demonstrate that none of the published infection countermeasures is robust against fault attacks. Finally, using randomness, we propose a set of enhanced countermeasures that thwart considered threats.

This paper demonstrates that magnitude squared incoherence (MSI) analysis is efficient to localize hot spots, i.e., points at which focused electromagnetic (EM) analyses can be applied with success. It is also demonstrated that MSI may be applied to enhance differential EM analyses (DEMA) based on difference of means (DoM).

Differential Power Analysis (DPA) is a powerful Side-Channel Attack (SCA) targeting as well symmetric as asymmetric ciphers. Its principle is based on a statistical treatment of power consumption measurements monitored on an Integrated Circuit (IC) computing cryptographic operations. A lot of works have proposed improvements of the attack, but no one focuses on ordering measurements. Our proposal consists in a statistical preprocessing which ranks measurements in a statistically optimized order to accelerate DPA and reduce the number of required measurements to disclose the key.

Side channel attacks are known to be efficient techniques to retrieve secret data. In this context, this paper concerns the evaluation of the robustness of triple rail logic against power and electromagnetic analyses on FPGA devices. More precisely, it aims at demonstrating that the basic concepts behind triple rail logic are valid and may provide interesting design guidelines to get DPA resistant circuits which are also more robust against DEMA.