Post-quantum cryptography
Is all our sensitive data about to be blown wide open? Steve Cassidy discovers how quantum changes the game
So what’s the connection between quantum and cryptography?
Quantum computing is a tricky topic, but you can think of it like this: in a quantum computer, a single bit of data can represent both zero and one simultaneously. These magical registers are called qubits, and if you stack a lot of them together you can perform mathematical operations on millions of different values at once – and then use probabilistic analysis on the results to extract the answer you’re looking for.
And the connection to code-breaking?
Many mainstream cryptographic systems are asymmetric. They rely on the fact that it’s quick and easy for a computer to multiply two prime numbers together, but much more time-consuming to reverse the operation and find the prime factors of a given number. In fact, the fastest computers we have today would take trillions of years to crack a 2,048-bit RSA encryption key. Quantum computing changes the game: it’s estimated that a quantum computer working with 20 million qubits could crack the same encryption key in just eight hours.