This week, Google published a paper describing how a quantum computer could theoretically derive a bitcoin private key in 9 minutes, with ramifications that stretch to Ethereum, other tokens, private banking, and potentially everything in the world.

Quantum computing is easy to mistake for a faster version of a regular computer. But it is not a more powerful chip or a bigger server farm. It is a fundamentally different kind of machine, different at the level of the atom itself.

A quantum computer starts with a very cold, very small loop of metal where particles begin to behave in ways they do not behave under normal conditions on Earth, ways that alter what we think of as the basic rules of physics.

Understanding what that means,…