“Someday, quantum mechanics may fundamentally change the way computers work. Right now, people can barely figure out how to make quantum computers add two 1-bit numbers, but who knows what will happen? Quantum computation techniques will render most public-key algorithms obsolete,” wrote Bruce Schneier 23 years ago in his classic security book Secrets & Lies.

“Someday” has started to arrive. Modern quantum computers could soon crush the mathematical problems that underpin many current encryption schemes. Is encryption dead? Not quite – the threat of losing classic encryption is leading to breakthroughs. But it’s a serious transition that decision-makers shouldn’t ignore.