SPHINCS: practical stateless hash-based signatures Daniel J. Bernstein1;3, Daira Hopwood2, Andreas Hülsing3, Tanja Lange3, Ruben Niederhagen3, Louiza Papachristodoulou4, Peter Schwabe4, and Zooko Wilcox O'Hearn2 1 Department of Computer Science University of Illinois at Chicago Chicago, IL 606077045, USA
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[email protected] Abstract. This paper introduces a high-security post-quantum stateless hash-based sig- nature scheme that signs hundreds of messages per second on a modern 4-core 3.5GHz Intel CPU. Signatures are 41 KB, public keys are 1 KB, and private keys are 1 KB. The signature scheme is designed to provide long-term 2128 security even against attackers equipped with quantum computers. Unlike most hash-based designs, this signature scheme is stateless, allowing it to be a drop-in replacement for current signature schemes. Keywords: post-quantum cryptography, one-time signatures, few-time signatures, hyper- trees, vectorized implementation 1 Introduction It is not at all clear how to securely sign operating-system updates, web-site certicates, etc. once an attacker has constructed a large quantum computer: RSA and ECC are perceived today as being small and fast, but they are broken in polynomial time by Shor's algorithm.