WHEN a powerful new technology comes around, people often split into two camps: those captivated by its benefits and those worried by the trouble it could unleash. This has happened with everything from knitting machines in the 16th century to artificial intelligence today.

It is, of course, a false dichotomy. As physicist and artificial intelligence researcher Max Tegmark put it in this magazine: “Are you the kind of person who thinks fire can kill people or the sort of person who thinks that fire can keep people warm in the winter? Both things are true, obviously.” (18 July 2020)

We are about to see this play out once again in the context of a technology that may come to define how we communicate in the 21st century: the quantum internet. It might seem like there is nothing wrong with the internet as we know it. Alas, not so. Quantum computers will eventually crack the encryption protocols that keep our web traffic secure, from bank transactions to private messages. This “cryptocalypse” could be only a few years away.

Quantum communications offer an unhackable alternative. One of their key features is that their fundamental units of information, quantum bits (or qubits), are very delicate. If anyone tries to read an encoded message, they will inevitably leave signs of having done so. This unhackable world isn’t as far away as you might think – as we report, we are already surprisingly good at making the infrastructure we will need to build it.

But as so often happens with tech advances, the unhackable privacy will cut both ways. The quantum internet will keep our credit card details secure, but it also means that people who want to talk in secret for nefarious purposes – whether it is terrorism or cybercrime – will have that option.

Democratic leaders have an abysmal record on policing our digital privacy. That needs to change, pronto. The quantum internet is coming, and when it arrives, it will make the privacy debate doubly tricky and unavoidable. As Tegmark put it: “The interesting question isn’t to argue for or against fire, it is to figure out how you can manage fire wisely.”