Symmetries and security of a quantum-public-key encryption based on single-qubit rotations

TL;DR

This paper analyzes the symmetries of a quantum-public-key encryption scheme based on single-qubit rotations, providing an improved upper bound on eavesdropper information and comparing attack strategies for robustness.

Contribution

It introduces a refined upper bound on information leakage and evaluates the security of the scheme against different types of quantum attacks.

Findings

Derived an improved upper bound on eavesdropper information.

Compared effectiveness of single-qubit and multi-qubit attack strategies.

Assessed the scheme's robustness against various quantum measurement attacks.

Abstract

Exploring the symmetries underlying a previously proposed encryption scheme which relies on single-qubit rotations, we derive an improved upper bound on the maximum information that an eavesdropper might extract from all the available copies of the public key. Subsequently, the robustness of the scheme is investigated in the context of attacks that address each public-key qubit independently. The attacks under consideration make use of projective measurements on single qubits and their efficiency is compared to attacks that address many qubits collectively and require complicated quantum operations.