Whether or not they’ll ever work, quantum computers pose a big enough threat to online security that cryptographers are already scrambling to adapt.
Try not to panic, but quantum computers stand poised to upend today’s information technology infrastructure. These revolutionary machines, though likely at least a decade off, could handily crack the encryption codes that protect everything from email to online shopping and banking, even classified government documents.
“With quantum computers, there is a real danger that the encryption algorithms we use today may be compromised,” says quantum physicist Andrew Shields of Toshiba. It’s one of many large companies investing in quantum computer-related initiatives — not just quantum computers, but also quantum encryption and networks. “If that does happen, the consequences could be very bad indeed.”
Online security today chiefly relies on two encryption schemes: RSA (named after its developers), based on factoring the product of two big prime numbers, and ECC (elliptic curve cryptography), rooted in the algebraic structure of points on a curve. These two methods create public keys and related private keys that encrypt data and create digital signatures (so your computer knows it really is Microsoft or McAfee sending you a software update).
Cracking encryption codes based on either scheme could take normal computer processors thousands of years because they perform operations one after the other, using bits, either 0 or 1.
Quantum computers, on the other hand, can do loads of operations simultaneously using “qubits.” These machines harness a quantum effect known as superposition, in which a qubit can somehow be both 0 and 1 at the same time. With enough qubits at its disposal, a quantum computer could slash through today’s encryption within minutes or seconds.