Here’s what you’ll learn when you read this story: - Current quantum computers don’t possess enough qubits to crack classical encryption methods, but a flurry of new research suggests that the threshold for such a breach could require drastically fewer qubits than previously estimated. - Until recently, researchers thought that 20 million qubits would be needed to crack schemes like elliptic-curve cryptography (ECC), but a new preprint from Caltech revises that number down to just 10,000. - This improved performance is mostly derived from improved error correction through non-local communication, which increases a quantum computer’s fault tolerance. The forthcoming era of quantum computers holds a lot of promise. Qubits—the quantum version of classical bits—have the potential to solve immensely complicated problems that today’s computers could never hope to tackle, thanks to their ability to leverage the quantum mechanical properties of superposition and entanglement. But with great power comes great responsibility, and these quantum technologies also have the dangerous ability to break classic cryptographic schemes like elliptic-curve cryptography (ECC, which is the backbone of cryptocurrencies like bitcoin) and 2048-bit RSA (one of the oldest public-key cryptosystems), which ensure the security of our online lives. Until relatively recently, researchers estimated that quantum computers likely needed at least 20 million qubits in order to break through these types of cryptosystems, but a new study by researchers at Caltech has drastically revised those numbers down to as low as 10,000 qubits. At the moment, no quantum computer is close to this number—Caltech recently revealed its 6,100-qubit array in late 2025, and most commercial quantum computers hover around 1,000 qubits max. But the newly revised estimate—detailed in a paper uploaded to the preprint server arXiv— means that an encryption apocalypse is probably closer than we thought. At the heart of this breakthrough is a new