Cryptology ePrint Archive: Report 2020/427

Improving the Performance of the Picnic Signature Scheme

Daniel Kales and Greg Zaverucha

Abstract: Picnic is a digital signature algorithm designed to provide security against attacks by quantum computers. The design uses only symmetric-key primitives, and is an efficient instantiation of the MPC-in-the-head paradigm. In this work, we explore the Picnic design in great detail. We investigate and benchmark different parameter choices and show that there exist better parameter choices than those in the current specification. We also present improvements to the MPC protocol that shorten signatures and reduce signing time. The proposed MPC changes tailor the protocol to the circuit of interest in Picnic, but may also be of independent interest. Taken together, these changes give a new instantiation of Picnic that signs messages 7.9 to 13.9 times faster, and verifies signatures 4.5 to 5.5 times faster than the existing ``Picnic2'' design, while having nearly the same signature sizes.

Category / Keywords: public-key cryptography / post-quantum cryptography, digital signatures, efficient implementation, zero-knowledge, MPC-in-the-head,

Date: received 14 Apr 2020, last revised 5 May 2020

Contact author: gregz at microsoft com,daniel kales@iaik tugraz at

Available format(s): PDF | BibTeX Citation

Version: 20200505:093843 (All versions of this report)

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