Practical quantum tokens: challenges and perspectives

TL;DR

This paper reviews the development, physical implementations, and future prospects of quantum tokens, highlighting their potential in secure quantum payments and their integration into the broader information security landscape.

Contribution

It provides a comprehensive overview of current quantum token realizations, discusses their challenges, and explores their future applications and relationship with post-quantum cryptography.

Findings

Multiple physical realizations of quantum tokens with quantum memories

Quantum tokens can be used for secure quantum digital payments

Discussion of quantum tokens' role in future security ecosystems

Abstract

The concept of quantum tokens dates back alongside quantum cryptography to Stephen Wiesner's seminal work in 1983[1]. Already this initial work proposes society-relevant applications such as secure quantum banknotes, which can be exchanged between a bank and a customer. This quantum currency is based on various physical states that can be easily verified but is protected from being copied by the fundamental quantum laws. Four decades later, these ideas have flourished in the field of quantum information, and the concept of quantum banknotes has not only adopted many varying names, such as quantum money, quantum coins, quantum-digital payments, and quantum tokens, but also reached its first experimental demonstrations. In this perspective article, we discuss the current state-of-the-art of quantum tokens in the field of quantum information, as well as their future perspectives. We present a number of physical realizations of quantum tokens with integrated quantum memories and their applicability scenarios in detail. Finally, we discuss how quantum tokens fit into the information security ecosystem and consider their relationship to post-quantum cryptography.