Cryptology ePrint Archive: Report 2019/1086

The SPHINCS+ Signature Framework

Daniel J. Bernstein and Andreas Hülsing and Stefan Kölbl and Ruben Niederhagen and Joost Rijneveld and Peter Schwabe

Abstract: We introduce SPHINCS+, a stateless hash-based signature framework. SPHINCS+ has significant advantages over the state of the art in terms of speed, signature size, and security, and is among the nine remaining signature schemes in the second round of the NIST PQC standardization project. One of our main contributions in this context is a new few-time signature scheme that we call FORS. Our second main contribution is the introduction of tweakable hash functions and a demonstration how they allow for a unified security analysis of hash-based signature schemes. We give a security reduction for SPHINCS+ using this abstraction and derive secure parameters in accordance with the resulting bound. Finally, we present speed results for our optimized implementation of SPHINCS+ and compare to SPHINCS-256, Gravity-SPHINCS, and Picnic.

Category / Keywords: public-key cryptography / Digital signature, post-quantum cryptography, SPHINCS, hash-based signatures, stateless, tweakable hash functions, NIST PQC, exact security

Original Publication (with major differences): CCS 2019

Date: received 23 Sep 2019

Contact author: contact at sphincs org

Available format(s): PDF | BibTeX Citation

Version: 20190925:133302 (All versions of this report)

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