We deal with the radix-r representation used for the scalar multiplication of pairing-based cryptosystems with characteristic r. Our goal of this paper is to present some invariant properties about the signed radix-r representation; (1) approximation formulae for the average significant length and the average hamming weight of gNAF and wrNAF representation, (2) some classification formulae of e...

Random delays are commonly used as a countermeasure to inhibit side channel analysis and fault attacks in embedded devices. This paper proposes a different manner of generating random delays. The alternative proposed increases the desynchronisation compared to uniformly distributed random delays. It is also shown that it is possible to reduce the amount of time lost due to random delays, while ...

On smart-cards, Elliptic Curve Cryptosystems (ECC) can be vulnerable to Side Channel Attacks such as the Re ned Power Analysis (RPA). This attack takes advantage of the apparition of special points of the form (0, y). In this paper, we propose a new countermeasure based on co-Z formulæ and an extension of the curve isomorphism countermeasure. It permits to transform the base point P = (x, y) in...

To guarantee the security of a cryptographic implementation against Side Channel Attacks, a common approach is to formally prove the security of the corresponding scheme in a model as pertinent as possible. Nowadays, security proofs for masking schemes in the literature are usually conducted for models where only the manipulated data are assumed to leak. However in practice, the leakage is bett...

This document discusses masking approaches with a special focus on the AES S-box. Firstly, we discuss previously presented masking schemes with respect to their security and implementation. We conclude that algorithmic countermeasures to secure the AES algorithm against side-channel attacks have not been resistant against all first-order side-channel attacks. In this article, we introduce a new...

In recent years, different instruction set extensions for cryptography have been proposed for integration into general-purpose RISC processors. Both public-key and secret-key algorithms can profit tremendously from a small set of custom instructions specifically designed to accelerate performance-critical code sections. While the impact of instruction set extensions on performance and silicon a...

Over a decade, cryptographers are more attentive on designing lightweight ciphers in focus to compact cryptographic devices. More often, the security of these algorithms are defined in terms of its resistance to mathematical cryptanalysis methods. Nevertheless, designers are well aware of implementation attacks and concentrating on new design strategies to improve the defence quality against im...

Attacks that use side channels, such as sound and electromagnetic emanation, to infer keystrokes on physical keyboards are ineffective on smartphones without physical keyboards. We describe a new side channel, motion, on touch screen smartphones with only soft keyboards. Since typing on different locations on the screen causes different vibrations, motion data can be used to infer the keys bein...

Recent works have looked at how to use human knowledge or computability in order to define or to achieve security. We take this approach one step further, and suggest to use cryptanalytic attacks in the human computational model. We have identified several instances where side channel attacks on human beings may be useful. We show for each of these cases the appropriate use of side channel atta...

Recently, the side channel keeps the attention of researchers in theory of pairing, since, several studies have been done in this subject and all they have the aim in order to attack the cryptosystems of Identification Based Encryption (IBE) which are integrated into Smart Cards (more than 80% of those cryptosystems are based on a pairing). The great success and the remarkable development of th...