“So, he’s the Beyoncé of this event?” a young woman standing behind me says to a colleague. The three of us are standing, looking at the back of a crowd, whose members are all looking at a bearded man in an orange sweater. Getting a look at him is like trying to see the Mona Lisa – only fleeting glimpses are possible. “His algorithm is the algorithm that will break everything,” the colleague says, as I briefly catch sight of people posing for selfies and getting their conference badges signed. I’m at the Quantum.Tech World conference in Boston, and Peter Shor is the star attraction. Shor is one of the most influential researchers in the history of quantum computing, and it all comes down to his creation, known as Shor’s algorithm. In the 1990s, Shor was a researcher at Bell Labs in New Jersey. Quantum computers were a somewhat obscure research topic, barely on his radar, until he attended a seminar by the quantum computing pioneer Umesh Vazirani. There, he heard about a problem that quantum computers could solve better than any conventional computer. The problem was extremely contrived, so Shor wondered whether there was something more practical that quantum computers could be good at, too. Over the course of about six months, culminating in the spring of 1994, he not only identified such a problem – the factoring of very large numbers – but he also developed a recipe that a quantum computer could follow to solve it. Shor’s algorithm, the one that could “break everything”, was born. It quickly became recognised as an outstanding contribution to the field and gave researchers an urgent reason to actually build quantum computers. Most modern encryption relies on the mathematical task of factoring very large numbers. As long as computers struggle with