A Formal Proof of Countermeasures against Fault Injection Attacks on CRT-RSA

Pablo Rauzy (1) , Sylvain Guilley (2)

1 LTCI - Laboratoire Traitement et Communication de l'Information
2 SSH - Secure and Safe Hardware

In this article, we describe a methodology that aims at either breaking or proving the security of CRT-RSA algorithms against fault injection attacks. In the specific case-study of BellCoRe attacks, our work bridges a gap between formal proofs and implementation-level attacks. We apply our results to three versions of CRT-RSA, namely the naive one, that of Shamir, and that of Aumüller et al. Our findings are that many attacks are possible on both the naive and the Shamir implementations, while the implementation of Aumüller et al. is resistant to all fault attacks with one fault. However, we show that the countermeasure is not minimal, since two tests out of seven are redundant and can simply be removed.

Mots clés: RSA; CRT; fault injection; BellCoRe attack; formal proof; OCaml

Domaines: Cryptographie et sécurité [cs.CR]

Pablo Rauzy, Sylvain Guilley. A Formal Proof of Countermeasures against Fault Injection Attacks on CRT-RSA. PROOFS, Aug 2013, Santa Barbara, CA, United States. ⟨hal-00863914v1⟩