SPARX - A Side-Channel Protected Processor for ARX-based Cryptography

Florian Bache1,a, Tobias Schneider2, Amir Moradi2 and Tim Güneysu1,3,b
1University of Bremen, Germany.
2Horst Görtz Institute for IT Security, Ruhr-Universität Bochum, Germany.
3Cyber Physical Systems, DFKI GmbH, Bremen, Germany


ARX-based cryptographic algorithms are composed of only three elemental operations addition, rotation and exclusive or which are mixed to ensure adequate confusion and diffusion properties. While ARX-ciphers can easily be protected against timing attacks, special measures like masking have to be taken in order to prevent power and electromagnetic analysis. In this paper we present a processor architecture for ARXbased cryptography, that intrinsically guarantees first-order SCA resistance of any implemented algorithm. This is achieved by protecting the complete data path using a Boolean masking scheme with three shares.
We evaluate our security claims by mapping an ARX-algorithm to the proposed architecture and using the common leakage detection methodology based on Student's t-test to certify the side-channel resistance of our processor.

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