Britain's top cyber spy said on Friday that quantum computing was coming closer but that it posed a potential risk as adversaries could use such computing power to breach modern encryption and potentially look backwards to steal secrets.
"Quantum computing is coming closer - its still some way off depending on who you talk to," GCHQ Director Jeremy Fleming said after a lecture at Imperial College London.
He added that there were both opportunities and risks from quantum computers - which use the phenomena of quantum mechanics to deliver a leap forward in computation.
"That means we need to get ahead of the curve - we need to be designing quantum-resistant algorithms, we need to be designing quantum-proof cyber security approaches such that we're prepared for the future when it comes but so we're also prepared for those adversaries who might use a quantum computer to look back at things that we currently think are secure."