Paper 2019/781

BBQ: Using AES in Picnic Signatures

Cyprien Delpech de Saint Guilhem and Lauren De Meyer and Emmanuela Orsini and Nigel P. Smart

Abstract

This works studies the use of the AES block-cipher for Picnic-style signatures, which work in the multiparty-computation-in-the-head model. It applies advancements to arithmetic circuits for the computation of the AES S-box over multiparty computation in the preprocessing model to obtain an improvement of signature sizes of 40\% on average compared to using binary circuits for AES-128, AES-192 and AES-256 in combination with previous techniques. This work also discusses other methods for the computation of the S-box and provides insights into the reaches and limits of the multiparty-computation-in-the-head paradigm.