A Simple Construction of Quantum Public-Key Encryption from Quantum-Secure One-Way Functions

TL;DR

This paper presents a straightforward method to construct quantum public-key encryption schemes using only quantum-secure one-way functions, achieving strong security with classical ciphertexts, thus simplifying assumptions compared to classical schemes.

Contribution

It introduces a simple construction of quantum PKE from quantum-secure one-way functions, requiring only classical ciphertexts and achieving CCA security.

Findings

Quantum PKE can be built from quantum-secure one-way functions.

The scheme uses only classical ciphertexts.

It satisfies strong CCA security.

Abstract

Quantum public-key encryption [Gottesman; Kawachi et al., Eurocrypt'05] generalizes public-key encryption (PKE) by allowing the public keys to be quantum states. Prior work indicated that quantum PKE can be constructed from assumptions that are potentially weaker than those needed to realize its classical counterpart. In this work, we show that quantum PKE can be constructed from any quantum-secure one-way function. In contrast, classical PKE is believed to require more structured assumptions. Our construction is simple, uses only classical ciphertexts, and satisfies the strong notion of CCA security.