## Cryptology ePrint Archive: Report 2017/632

Generalized Polynomial Decomposition for S-boxes with Application to Side-Channel Countermeasures

Dahmun Goudarzi and Matthieu Rivain and Damien Vergnaud and Srinivas Vivek

Abstract: Masking is a widespread countermeasure to protect implementations of block-ciphers against side-channel attacks. Several masking schemes have been proposed in the literature that rely on the efficient decomposition of the underlying s-box(es). We propose a generalized decomposition method for s-boxes that encompasses several previously proposed methods while providing new trade-offs. It allows to evaluate $n\lambda$-bit to $m\lambda$-bit s-boxes for any integers $n,m,\lambda \geq 1$ by seeing it a sequence of $m$ $n$-variate polynomials over $\mathbb{F_{2^\lambda}}$ and by trying to minimize the number of multiplications over $\mathbb{F_{2^\lambda}}$.

Category / Keywords: s-box decomposition, side-channel countermeasure, masking, software implementation, block cipher

Original Publication (in the same form): IACR-CHES-2017

Date: received 27 Jun 2017, last revised 27 Jun 2017

Contact author: dahmun goudarzi at cryptoexperts com,matthieu rivain@gmail com,damien vergnaud@ens fr, sv venkatesh@bristol ac uk

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2017/632

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