### Mutual Information Analysis -- A Universal Differential Side-Channel Attack

Benedikt Gierlichs, Lejla Batina, and Pim Tuyls

##### Abstract

In this paper, we develop an information theoretic differential side-channel attack. An embedded device containing a secret key is modeled as a black box with a leakage function whose output is captured by an adversary through the noisy measurement of a physical observable e.g. the power consumed by the device. We assume only that the measured values depend somehow on the leakage and thus on the word being processed by the device. Without any knowledge on the particular dependency, this fact is exploited to mount a side-channel attack. We build a distinguisher which uses the Mutual Information between the observed and the leaked values as a statistical test. The Mutual Information is maximal when the hypothetical key guessed by the attacker equals the key in the device. Our approach is confirmed by experimental results. We perform power analysis on an embedded device using our Mutual Information based distinguisher and show that the correct key is clearly distinguishable. Finally, our approach allows to compute a good estimate of the minimal number of traces required to perform a successful attack and gives an upper bound on the information leakage in a single observation.

Available format(s)
Category
Applications
Publication info
Published elsewhere. Unknown where it was published
Keywords
Differential Side Channel AnalysisInformation TheoryMutual Information
Contact author(s)
benedikt gierlichs @ esat kuleuven be
History
2007-06-20: revised
See all versions
Short URL
https://ia.cr/2007/198

CC BY

BibTeX

@misc{cryptoeprint:2007/198,
author = {Benedikt Gierlichs and Lejla Batina and Pim Tuyls},
title = {Mutual Information Analysis -- A Universal Differential Side-Channel Attack},
howpublished = {Cryptology ePrint Archive, Paper 2007/198},
year = {2007},
note = {\url{https://eprint.iacr.org/2007/198}},
url = {https://eprint.iacr.org/2007/198}
}

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