A Quantum Money Solution to the Blockchain Scalability Problem
arXiv:2002.11998 · doi:10.22331/q-2020-07-16-297
Abstract
We put forward the idea that classical blockchains and smart contracts are potentially useful primitives not only for classical cryptography, but for quantum cryptography as well. Abstractly, a smart contract is a functionality that allows parties to deposit funds, and release them upon fulfillment of algorithmically checkable conditions, and can thus be employed as a formal tool to enforce monetary incentives. In this work, we give the first example of the use of smart contracts in a quantum setting. We describe a simple hybrid classical-quantum payment system whose main ingredients are a classical blockchain capable of handling stateful smart contracts, and quantum lightning, a strengthening of public-key quantum money introduced by Zhandry (Eurocrypt'19). Our hybrid payment system employs quantum states as banknotes and a classical blockchain to settle disputes and to keep track of the valid serial numbers. It has several desirable properties: it is decentralized, requiring no trust in any single entity; payments are as quick as quantum communication, regardless of the total number of users; when a quantum banknote is damaged or lost, the rightful owner can recover the lost value.
arXiv commentThis work supersedes arXiv:1902.05214
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Cited by in corpus (5)
- A Survey and Comparison of Post-quantum and Quantum Blockchains
- Secure Software Leasing from Standard Assumptions
- Quantum cryptography beyond key distribution: theory and experiment
- Quantum Multi-Solution Bernoulli Search with Applications to Bitcoin's Post-Quantum Security
- Revisiting the Properties of Money