(PR33) (INCYBER) Side-channel security : from theory to practice

The security of cryptographic implementations relies on the confidentiality of secret and private keys, as well as on the integrity of public keys. Based on those, trustworthy protocols can be devised, in order to fulfill security applications, such as mutual authentication (in terms of identity) or remote attestation (in terms of firmware). Now, side-channel attacks unfortunately allow to recover keys without cryptanalyses, simply by spying on surreptitious emanations leaking out of the device under consideration. Many scholar works have been conducted to characterize such attacks. For instance, the novel book entitled "Mathematical Foundations for Side-Channel Analysis of Cryptographic Systems", published in 224 by the authors, exhibits several attack paths. The scientific community at large has proposed security bounds against such threats. They consist in a lower bound on the spied traces to recover enough information to recover the key. Now, those bounds relate to information theory notions and metrics. Nonetheless, the estimation of those quantities is not trivial. In this talk, we demonstrate how to connect attack complexity to number of traces to guess correctly the key, i.e., to the effort as described in the Common Criteria (CC). This application is useful for certification laboratories. Our presentation aims at presenting in a didactic manner the results presented at cryptographic conferences of highest rating. A translation into the normalisation language (incl. ISO/IEC 17825) will be presented.