We Need Quantum Money
Quantum computers require quantum money. This is urgent.
One stylized way to think about “money” is that it is, at its core, nothing more than an entry in a record-keeping system maintained by a bank. Historically, this system was represented in a physical ledger—a book where financial transactions were meticulously written down. Over time, this evolved into a digital format, a sort of virtual ledger book that banks use to keep track of money in the modern economy. When you deposit money, for example, the bank updates its ledger to show that you have a bit more in your account, and the person or entity that gave you the money has a bit less. This simple updating process is the backbone of financial transactions.
There are various methods of managing this record-keeping process. Blockchain, for instance, is a decentralized system designed to be a new and more secure way of keeping track of transactions. Yet, at its essence, whether banks use a giant leather-bound ledger book, an Excel spreadsheet, or advanced blockchain technology, the process is always about maintaining a list—an accurate and secure list that reflects the balances and transfers of assets.
This list is incredibly valuable and must be protected at all costs. One of the most important functions of a bank is to safeguard this list. If a malicious actor were to get their hands on these records and manipulate them, they could change the entries to make it look like they have much more money than they do. They could wipe out all their debts (see: Fight Club). The integrity of that list is critical not only for the reputation of the bank but also for the stability of the entire financial system. The trust that people place in banks, and by extension in the broader economy, hinges on the security of this list.
