At first we thought this might be a bit of hype. Turns out the concept goes back more than 50 years. Worth the read from the source. Link is below. Because Quantum is Coming. Qubit

Will Quantum Money Breed Quantum Crime?

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+  The challenge is to create a quantum state that can work as a form of money. Just like ordinary cash, quantum cash would be exchanged in lieu of goods. It would be sent and received over the internet without the need to involve third party parties such as banks and credit card companies. That would make transactions anonymous and difficult to trace, unlike today’s online transactions which always leave an electronic paper trail. That’s one big advantage over today’s money.

+  Last year, we looked at one scheme put forward by a group at the Massachusetts Institute of Technology in Cambridge. This group has been making and breaking quantum money schemes for some time now.

+  Their idea is to create quantum money that consists of two parts: a quantum state, like the quantum properties of a group of photons, and a classical serial number that is matched to the quantum state.

+  Any user of quantum money can verify that this money is kosher using a quantum algorithm running on a quantum computer. If the serial number matches the quantum state, the computer returns the money for future use. If it doesn’t match, the money must be a forgery. In this case the money is destroyed.

+  Today this group (or at least most of them) led by Edward Farhi put forward a new approach which they hope will be secure. Their quantum cash is based on a new kind of asymmetry: that two identical knots can look entirely different. So while it may be easy to make either knot, it is hard to find a way to transform one into the other.

Farhi and co say: “The purported security of our quantum money scheme is based on the assumption that given two different looking but equivalent knots, it is difficult to explicitly find a transformation that takes one to the other.”


+  What Farhi and co are hoping is that in 20 years, when a quantum internet capable of carrying quantum cash has finally been built, that the quantum knot conundrum will still look as asymmetric as it does now.

Source:  MIT Technology Review.  Emerging Technology from the arXiv,  Will Quantum Money Breed Quantum Crime?

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