Multi-Channel Currency: A Secure Method Using Semi-Quantum Tokens

Abstract

Digital currencies primarily operate online, but there is growing interest in enabling offline transactions to improve digital inclusion. Existing offline methods struggle with double-spending risks, often limiting transaction amounts. In this work, we propose a quantum-state-based currency system that uses the non-cloning theorem to enable secure, multi-channel transactions without the risk of double spending. We demonstrate this system's implementation with experimental results, including use cases for currency transfers and swaps. To mitigate credit risks in swaps, we also integrate blockchain to show its wide applicability. Our approach paves the way for quantum-secure digital currencies and opens new possibilities for optimizing multi-channel tokens.