Cryptology ePrint Archive: Report 2020/1508

A Combinatorial Approach to Quantum Random Functions

Nico Döttling and Giulio Malavolta and Sihang Pu

Abstract: Quantum pseudorandom functions (QPRFs) extend the classical security of a PRF by allowing the adversary to issue queries on input superposition. Zhandry [Zhandry, FOCS 2012] showed a separation between the two notions and proved that common construction paradigms are also quantum secure, albeit with a new ad-hoc analysis. In this work, we revisit the question of constructing QPRFs and propose a new method starting from small-domain (classical) PRFs: At the heart of our approach is a new domain-extension technique based on bipartite expanders. Interestingly, our analysis is almost entirely classical. As a corollary of our main theorem, we obtain the first (approximate) key homomorphic quantum PRF based on the quantum intractability of the learning with errors problem.

Category / Keywords: foundations / Quantum Random Function, Pseudorandom Function

Original Publication (with minor differences): IACR-ASIACRYPT-2020

Date: received 1 Dec 2020

Contact author: sihang pu at email com

Available format(s): PDF | BibTeX Citation

Version: 20201202:100715 (All versions of this report)

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