Cloud-based Semi-Quantum Money

TL;DR

This paper proposes a cloud-based semi-quantum money scheme that minimizes quantum resource reliance by using classical systems and semi-honest quantum clouds, enhancing practicality and security in quantum currency systems.

Contribution

It introduces a novel semi-quantum money scheme leveraging cloud-based quantum resources, reducing quantum requirements and improving feasibility over previous quantum money models.

Findings

Scheme relies on semi-honest quantum clouds for security.

Reduces quantum resource dependence to only the cloud.

Includes security analysis and resource estimation.

Abstract

In the 1970s, Wiesner introduced the concept of quantum money, where quantum states generated according to specific rules function as currency. These states circulate among users with quantum resources through quantum channels or face-to-face interactions. Quantum mechanics grants quantum money physical-level unforgeability but also makes minting, storing, and circulating it significantly challenging. Currently, quantum computers capable of minting and preserving quantum money have not yet emerged, and existing quantum channels are not stable enough to support the efficient transmission of quantum states for quantum money, limiting its practicality. Semi-quantum money schemes support fully classical transactions and complete classical banks, reducing dependence on quantum resources and enhancing feasibility. To further minimize the system's reliance on quantum resources, we propose a cloud-based semi-quantum money (CSQM) scheme. This scheme relies only on semi-honest third-party quantum clouds, while the rest of the system remains entirely classical. We also discuss estimating the computational power required by the quantum cloud for the scheme and conduct a security analysis.