## Cryptology ePrint Archive: Report 2012/728

Defensive Leakage Camouflage

E. Brier and Q. Fortier and R. Korkikian and K. W. Magld and D. Naccache and G. Ozari de Almeida and A. Pommellet and A. H. Ragab and J. Vuillemin

Abstract: This paper considers the transfer of digital data over {\sl leaky and noisy} communication channels. We develop defensive strategies exploiting the fact that noise prevents the attacker from accurately measuring leakage.

The defense strategy described in this paper pairs each useful data element $k$ with a camouflage value $v$ and simultaneously transmits both $k$ and $v$ over the channel. This releases an emission $e(k,v)$. We wish to select the camouflage values $v(k)$ as a function of $k$ in a way that makes the quantities $e(k,v(k))$ as {\sl indistinguishable} as possible from each other.

We model the problem and show that optimal camouflage values can be computed from side-channels under very weak physical assumptions. The proposed technique is hence applicable to a wide range of readily available technologies.

We propose algorithms for computing optimal camouflage values when the number of samples per trace is moderate (typically $\leq 6$) and justify our models by a statistical analysis.

We also provide experimental results obtained using FPGAs.

Category / Keywords: implementation / side channel attacks

Date: received 29 Dec 2012, last revised 1 Jan 2013

Contact author: david naccache at ens fr

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