In December 2024, Google unveiled Willow, its latest quantum chip, widely recognised as a significant milestone in quantum computing. With its exponential ability to reduce errors while scaling qubits and perform computations that are impossible for classical supercomputers, Willow highlights both the potential and the challenges of quantum technology. While this breakthrough moves us closer to practical quantum applications, it also raises pressing questions about its immediate impact on the security landscape.
Quantum computing is fundamentally different from classical computing, which relies on bits–binary units that are either 0 or 1. Quantum computers use qubits, which use the principles of quantum mechanics such as superposition and entanglement. Superposition allows qubits to exist in multiple states simultaneously, enabling them to perform many calculations at once. Imagine flipping a coin that can be both heads and tails at the same time, rather than just one or the other. Entanglement is a phenomenon where qubits become linked, so the state of one qubit is instantly connected to the state of another, no matter how far apart they are.
These statistical and probabilistic properties allow quantum computers to process certain types of information exponentially faster than classical systems. This is particularly advantageous for low level tasks like optimisation, material simulation, and cryptography–problems that are practically impossible for current cutting edge classical computers to solve.