Google changed the quantum computer game this week, with the release of Willow – an ultrapowerful, state-of-the-art chip. While tech enthusiasts cheered the breakthrough, the bitcoin crowd was much more subdued, with some raising concerns about the security of the blockchain.

So here’s the lowdown on Willow, quantum computing, and what it actually means for the OG crypto.

What are quantum computers, exactly?

Quantum computers are next-level machines that use the rules of quantum mechanics to solve problems that regular computers can’t handle. Instead of normal “bits” that are either 0 or 1, quantum computers use “qubits”.

Qubits can be 0 and 1 at the same time, and that makes them ridiculously good at crunching numbers. So with things like cryptography, simulations, or optimization problems – quantum computers can blow traditional ones out of the water.

And where does Google’s Willow fit in?

Qubits are the building blocks of quantum computers, but they do have one big problem: they become unstable and error-prone when too many of them work together. Since quantum computers need lots of qubits to run, building them has always been a massive challenge.

That’s what’s so exciting about Willow. Put simply, it’s a chip that helps these qubits play nice together – making them more “scalable”. In other words, Willow makes it easier to build big, powerful quantum computers that are far less mistake-prone.

Willow is fast, too: Google says it performed a “random circuit sampling (RCS)” calculation in under five minutes. To put that into perspective, the same calculation would take a regular supercomputer ten septillion years to solve (a really long time).

Now, Willow itself is made up of 105 qubits – which isn’t exactly a record number. IBM’s Condor processor, for example, has 1,121 qubits. But Willow’s qubits are built in a much more stable and efficient way (quality over quantity), which puts it way ahead of the competition.

Essentially: Willow is powerful – and it’s a total game-changer for quantum computing.

What does any of this have to do with bitcoin?

Right, to understand what Willow could mean for bitcoin, we first need to talk about mining – the process that secures the blockchain. Miners update the blockchain by trying to guess a random number called a “hash.” No single computer can guess the hash alone, but millions of mining machines working together can.

These mining machines run trillions of computations per second, and about every ten minutes, one miner successfully guesses the hash. That particular miner adds a new transaction block to the blockchain and earns some bitcoin as a reward. (That’s also how new coins are created, by the way).

You can read all about mining in our bitcoin guide, but here’s where the quantum computer fears come in. Some experts say that quantum computers could eventually overpower regular mining machines. And that could (in theory), give them some form of control over the blockchain – not a good thing.

So, is it all over for bitcoin?

Not exactly. Here are five reasons why I’m not too worried:

1. The bitcoin network could upgrade to “quantum-resistant cryptography” before quantum computers become a serious threat. Right now, bitcoin’s cryptography (the lock that secures it) uses something called SHA-256 – which might not stand up as well to quantum computers. But bitcoin developers are one step ahead here, and they’re already building post-quantum algorithms that could replace SHA-256. Willow’s just made that a more urgent priority.

2. Miners are like bitcoin's defense squad, and they could use quantum computers too. That would help them fend off any stronger attacks (from quantum computers) and keep the network secure.

3. Bitcoin’s “mining difficulty” automatically adjusts every two weeks (give or take) to make sure blocks are mined roughly every ten minutes, not faster. And the proof is in the chart below: bitcoin’s hash rate (the total computational power used by miners) has kept climbing as mining machines have upped the ante. So even if quantum computers tried to mine faster, the network would raise the mining difficulty. The hash rate would go up with it, and the blocks would still take ten minutes to mine.

That also means quantum computers can’t create new bitcoin any faster – and the 21 million total coin supply cap still stands.

4. Bitcoin transactions get exponentially harder to reverse with each passing block. Cryptographer Nick Szabo explained blockchain security with a simple analogy: a transaction in the blockchain is like a fly trapped in amber. The more amber that sets around the fly, the harder it is for the fly to escape. So the further back you go in blockchain time, the lower the threat posed by quantum computers.

5. Bitcoin is protected by the principle of game theory. In other words, the system incentivizes everyone to play by the rules – and penalizes them if they don’t. Even with quantum computers, it would likely cost trillions to try to “break” bitcoin. You’d need to build and run a quantum computer powerful enough to outpace the entire mining network.

If it were me, I’d use those resources to mine bitcoin instead.