Franchised Quantum Money

TL;DR

This paper introduces franchised quantum money, a new type of quantum currency that is easier to construct, secure against counterfeiting, and allows local verification without bank communication, based on standard cryptographic assumptions.

Contribution

It proposes franchised quantum money, providing a practical construction with security based on one-way functions, and introduces the concept of sabotage security.

Findings

Constructed franchised quantum money scheme

Proved security assuming one-way functions

Scheme allows local verification without bank communication

Abstract

The construction of public key quantum money based on standard cryptographic assumptions is a longstanding open question. Here we introduce franchised quantum money, an alternative form of quantum money that is easier to construct. Franchised quantum money retains the features of a useful quantum money scheme, namely unforgeability and local verification: anyone can verify banknotes without communicating with the bank. In franchised quantum money, every user gets a unique secret verification key, and the scheme is secure against counterfeiting and sabotage, a new security notion that appears in the franchised model. Finally, we construct franchised quantum money and prove security assuming one-way functions.