The impact of quantum computing on cryptography

Quantum computing has been heralded by some as the death of cryptography as we know it. Yet the quantum computers that exist today can't perform more complex operations than tasks such as factoring 15 into 3×5, so they're pretty useless. A useful quantum computer would need to be large and reliable enough to perform operations involving thousands or millions of quantum bits (qubits) in order to break cryptographic algorithms widely used today. Quantum computing has been heralded by some as the death of cryptography, although such machines are still in the early stages of development. We don't yet know how hard it is to build a scalable, fault-tolerant quantum computer, but we should be prepared and understand the real impact of quantum computing on our networks' security. Jean-Philippe Aumasson of Kudelski looks at how quantum computers work, the algorithms that run on them and the potential impact on cryptography. © 2017 Elsevier Ltd