Shor's Up: Google's Quantum Paper Shows Bitcoin's Private Keys Could Be Cracked in 9 Minutes

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. For anyone holding crypto, that's less time than it takes to brew a decent cup of coffee—or for that matter, less time than most people spend doomscrolling before realizing they've lost their morning.

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. It's like the difference between a really buff bodybuilder and someone who can walk through walls.

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. We're talking cold enough that your ex's heart feels warm by comparison.

Understanding what that means, physically, is the difference between reading about the quantum threat and actually grasping it. Most people bounce off this stuff like a Wi-Fi signal hitting a Faraday cage, and honestly, that's fair.

How computers and quantum computers actually work

Regular computers store information as bits — each is either a 0 or a 1. A bit is a tiny switch. Physically, it's a transistor on a chip — a microscopic gate that either lets electricity through (1) or doesn't (0). Every photo, every bitcoin transaction, every word you've ever typed is stored as patterns of these switches being on or off. There is nothing mysterious about a bit; it is a physical object in one of the two definite states. Every calculation is just shuffling these 0s and 1s around really fast. A modern chip can do billions of these per second, but it still does them one at a time, in sequence. It's basically a very fast, very obedient accountant who can only count one penny at a time but does it billions of times per second.

Quantum computers use something known as qubits instead of bits. A qubit can be 0, 1, or — and this is the weird part — both at the same time! This is possible as a qubit is a completely different kind of physical object. The most common version, and the one Google uses, is a tiny loop of superconducting metal cooled to about 0.015 degrees above absolute zero, colder than outer space but here on Earth. That's not cold. That's "my hard drive is having an existential crisis" cold.

At that temperature, electricity flows through the loop without any resistance, and the current is said to exist in a quantum state. In the superconducting loop, current can flow clockwise (call that 0) or counterclockwise (call that 1). But at quantum scales, the current does not have to pick one direction and actually flows in both directions simultaneously. Don't mistake it for switching between the two really fast. The current is measurably, experimentally and verifiably in both states simultaneously. It's not indecisive. It's just very, very progressive.

Mind-bending physics

With us so far? Great, because here's where it gets genuinely strange. The physics behind how it works isn't immediately intuitive, and it is not supposed to be. Everything someone interacts with in daily life obeys classical physics, which assumes that things are in one place at one time. But particles do not behave this way at the subatomic scale. An electron does not have a definite position until you look at it. A photon does not have a definite polarization until you measure it. A current in a superconducting loop does not flow in a definite direction until you force it to pick. The universe, it turns out, is a massive troll who only decides what happens when you check.

The reason we don't experience this in everyday life is decoherence. When a quantum system interacts with its environment — air molecules, heat, vibrations and light — the superposition collapses almost instantly. A football cannot be in two places at once because it is interacting with trillions of air molecules, dust, sound, heat, gravity, etc., every nanosecond. But isolate a tiny current in a near-absolute-zero vacuum, shield it from every possible disturbance, and the quantum behavior survives long enough to compute with. That's why quantum computers are so hard to build. People are engineering physical environments where the laws of physics that normally prevent this stuff from happening are held at bay for just long enough to run a calculation. It's basically asking physics very nicely to look the other way for a few milliseconds.

Google's machines operate in dilution refrigerators the size of huge rooms, colder than anything in the natural universe, surrounded by layers of shielding against electromagnetic noise, vibration, and thermal radiation. And the qubits are fragile even then. They lose their quantum state constantly, which is why error correction dominates every conversation about scaling up. These things are more high-maintenance than a prize-winning orchid in a hurricane.

So quantum computing is not a faster version of classical computing. It is exploiting a different set of physical laws that only apply at extremely small scales, extremely low temperatures, and extremely short timeframes. Now stack that up. Two regular bits can be in one of four states (00, 01, 10, 11), but only one at a time. Two qubits can represent all four states at once. Three qubits represent eight states. Ten qubits represent 1,024. Fifty qubits represent over a quadrillion. The number doubles with every qubit that is added, which is why