## Cryptology ePrint Archive: Report 2014/357

Simulatable Leakage: Analysis, Pitfalls, and new Constructions

J. Longo Galea and D. Martin and E. Oswald and D. Page and M. Stam and and M. Tunstall

Abstract: In 2013, Standaert \emph{et al.} proposed the notion of simulatable leakage to connect theoretical leakage resilience with the practice of side channel attacks. Their use of simulators, based on physical devices, to support proofs of leakage resilience allows verification of underlying assumptions: the indistinguishability game, involving real vs. simulated leakage, can be played' by an evaluator. Using a concrete, block cipher based leakage resilient PRG and high-level simulator definition (based on concatenating two partial leakage traces), they included detailed reasoning why said simulator (for AES-128) resists state-of-the-art side channel attacks. \\\\ In this paper, we demonstrate a distinguisher against their simulator and thereby falsify their hypothesis. Our distinguishing technique, which is evaluated using concrete implementations of the Standaert \emph{et al.} simulator on several platforms, is based on tracking' consistency (resp. identifying simulator {\em in}consistencies) in leakage traces by means of cross-correlation. In attempt to rescue the approach, we propose several alternative simulator definitions based on splitting traces at points of low intrinsic cross-correlation. Unfortunately, these come with significant caveats, and we conclude that the most natural way of producing simulated leakage is by using the underlying construction `as is' (but with a random key).

Category / Keywords: leakage resilience, side channel attack, simulatable leakage, cross-correlation

Original Publication (with minor differences): IACR-ASIACRYPT-2014

Date: received 21 May 2014, last revised 17 Sep 2014

Contact author: Elisabeth Oswald at bristol ac uk

Available format(s): PDF | BibTeX Citation

Note: Revision for updated title, author list and to reflect the ASIACRYPT submission.

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