By: Edward Eaton, Security Researcher, ISARA Corporation
Date: originally posted to the IACR Cryptology ePrint Archive on 22 Jun 2017
Abstract: Digital signatures constructed solely from hash functions offer competitive signature sizes and fast signing and verifying times. Moreover, the security of hash functions against a quantum adversary is believed to be well understood. This means that hash-based signatures are strong candidates for standard use in a post-quantum world. The Leighton-Micali signature scheme (LMS) is one such scheme being considered for standardization. However, all systematic analyses of LMS have only considered a classical adversary. In this work, we close this gap by showing a proof of the security of LMS in the quantum random-oracle model. Our results match the bounds imposed by Grover’s search algorithm within a constant factor and remain tight in the multi-user setting.
Category / Keywords: public-key cryptography / Post-Quantum Cryptography, Digital Signatures, Hash Functions, Random Oracles, Multi-User Setting
Original Publication (with minor differences): 24th Annual Conference on Selected Areas in Cryptography (SAC2017)
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