In partnership with
Google Quantum AI just published a research paper with the Ethereum Foundation, Stanford, and UC Berkeley.
It’s about what quantum computers will do to cryptocurrency.
And after reading all 57 pages, I can tell you this: the crypto community is not ready for what’s coming.
This paper gives exact numbers. Exact qubit counts. Exact attack times. No vague “sometime in the future” talk. Real math.
If you hold crypto, don’t skip this one.
Why Your Keys Aren’t Safe Forever
Every crypto transaction you make is protected by a math problem called ECDLP. You don’t need to remember the name. Just know this: it’s the lock on your wallet.
You have a private key (the secret) and a public key (the address). The whole system works because nobody can figure out your private key from your public key.
Classical computers can’t do it. It would take billions of years.
Quantum computers can.
There’s an algorithm called Shor’s algorithm that can solve this problem fast. The question was always: how big does the quantum computer need to be?
Google just answered that.
And the answer is smaller than most people thought.
The Actual Numbers
The team built two versions of their quantum circuit for breaking Bitcoin’s specific encryption curve (secp256k1).
Version one: 1200 logical qubits, 90 million Toffoli gates.
Version two: 1450 logical qubits, 70 million Toffoli gates.
A qubit (short for quantum bit) is the basic unit of information in quantum computing, serving as the quantum equivalent of the classical bit.
While a classical bit can only be a 0 or a 1 (like a light switch that is either off or on), a qubit is a two-state quantum-mechanical system that leverages the unique laws of physics to process information in a more complex way.
Now, logical qubits need error correction, so you need more physical qubits to make them work. Even after all that overhead, the researchers estimate this runs on fewer than half a million physical qubits.
Previous best estimate? About 9 million physical qubits. Google just cut that by roughly 20x.
But here’s what really matters.
The quantum computer can precompute the first half of the attack ahead of time. So when your public key shows up in a transaction, the actual key-breaking takes about 9 minutes.
Bitcoin’s average block time? 10 minutes.
That’s insane..
