Quantum computers need just 10,000 qubits — not the millions we assumed — to break the world's most secure encryption algorithms

Previous error-correction schemes require hundreds of physical qubits per logical qubit, but the new scheme, depicted on the right, reduces this overhead by more than 100-fold. (Image credit: Caltech/Robert Hurt (IPAC-SELab)) Copy link Facebook X Whatsapp Reddit Pinterest Flipboard Email Share this article 0 Join the conversation Follow us Add us as a preferred source on Google Newsletter Sign up for the Live Science daily newsletter now Get the world’s most fascinating discoveries delivered straight to your inbox. By submitting your information you agree to the Terms & Conditions and Privacy Policy and are aged 16 or over. You are now subscribed Your newsletter sign-up was successful Want to add more newsletters? Join the club Get full access to premium articles, exclusive features and a growing list of member rewards. Explore An account already exists for this email address, please log in. Subscribe to our newsletter Quantum computers don't need to be nearly as powerful as we thought to break the world's most secure encryption algorithms, scientists warn. New research claims that quantum computers can make widely used cryptographic security systems obsolete with far fewer quantum bits, or qubits , than scientists have widely predicted ‪—‬ leaving sensitive data, like banking information and private messages, thought to be protected by encryption, open to interception. Quantum computers run calculations in parallel, rather than in sequence, meaning that increasing the number of qubits that power them exponentially boosts their performance. Theoretically, this means the machines could one day solve calculations in seconds that would take the fastest supercomputers millions of years to complete. One example of such a calculation is Shor's algorithm. This quantum algorithm, designed in 1994 by mathematician Peter Shor, can efficiently factorize large numbers. It was the first evidence that quantum computers could theoretically outperform classical computers in a practical problem. Because it is virtually unbreakable by classical means, it has become the basis for RSA public-key encryption, which is behind many of the world's leading encryption schemes. Scientists previously assumed that you would need a system with millions of qubits to break Shor's algorithm using a quantum computer — a far cry from today's best processors, which have just hundreds of qubits. But now, a surprising new study uploaded March 31 to the arXiv preprint database warns it could be viable to solve this algorithm with a system that has just 10,000 qubits. Worse yet, the authors argue that a quantum computer with just 26,000 qubits could take as little as seven months to crack RSA-2048 encryption, the industry encryption standard used to protect most digital certificates on the internet. Sign up for the Live Science daily newsletter now Get the world’s most fascinating discoveries delivered straight to your inbox. Building error-free quantum computers The reason behind this