## Cryptology ePrint Archive: Report 2016/572

Faster Evaluation of SBoxes via Common Shares

Jean-Sebastien Coron and Aurelien Greuet and Emmanuel Prouff and Rina Zeitoun

Abstract: We describe a new technique for improving the efficiency of the masking countermeasure against side-channel attacks. Our technique is based on using common shares between secret variables, in order to reduce the number of finite field multiplications. Our algorithms are proven secure in the ISW probing model with $n \geq t+1$ shares against $t$ probes. For AES, we get an equivalent of $2.8$ non-linear multiplications for every SBox evaluation, instead of $4$ in the Rivain-Prouff countermeasure. We obtain similar improvements for other block-ciphers. Our technique is easy to implement and performs relatively well in practice, with roughly a 20% speed-up compared to existing algorithms.

Category / Keywords: secret-key cryptography / Side-channel attacks, ISW countermeasure, masking.

Original Publication (with minor differences): IACR-CHES-2016

Date: received 3 Jun 2016, last revised 7 Jun 2016

Contact author: jean-sebastien coron at uni lu, a greuet at oberthur com, r zeitoun at oberthur com, e prouff at gmail com

Available format(s): PDF | BibTeX Citation

Short URL: ia.cr/2016/572

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