Quantum computers need just 10,000 qubits — not the millions we assumed — to break the world's most secure encryption algorithms Future quantum computers will need to be far less powerful than we thought to threaten the security of encrypted messages, banking information and other sensitive data. Get the world’s most fascinating discoveries delivered straight to your inbox. 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. 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