The original version of this story appeared in Quanta Magazine.
Hard problems are usually not a welcome sight. But cryptographers love them. That’s because certain hard math problems underpin the security of modern encryption. Any clever trick for solving them will doom most forms of cryptography.
Several years ago, researchers found a radically new approach to encryption that lacks this potential weak spot. The approach exploits the peculiar features of quantum physics. But unlike earlier quantum encryption schemes, which only work for a few special tasks, the new approach can accomplish a much wider range of tasks. And it could work even if all the problems at the heart of ordinary