Data security is reliant on mathematical difficulty: put simply, it's easier to encrypt something than it is to decrypt it. This is fine in practice, but means that even the most secure messages could be easily cracked in ten years. Spies and surveillance targets are engaged in a never-ending game of cat-and-mouse.
This could all change: what if it were possible to send a message that wasn't protected by the limits of practical computing power, but by the laws of physics? This is the future promised by quantum communication. One straight-forward way to make the internet harder to intercept would be to make fibre-optic cables harder to tap. Information travels in short bursts of light down these cables; under seas and through cities. These bursts of light, though, can be intercepted by intelligence agencies and others by using a prism or beam splitter. This is invisible to the sender and recipient, and slows down the signal transmission only by an undetectable amount.
This changes if we can send a single photon at a time down the cable. As you can't split a photon with a prism, any attempt to intercept the signal would throw up errors or be detectable by the intended receiver. A key feature of quantum mechanics is that examining something changes it. This causes headaches for researchers, but means that in a quantum internet, if someone intercepts a message, they'll introduce changes and alert the people communicating. Such measures will transform the internet. Even as authorities battle tech giants over encryption, something much more significant is coming.
James Ball was among the Pulitzer-Prize-winningGuardianjournalists who worked on the Edward Snowden leaks, and is author of Post-Truth: How Bullshit Conquered The World.
This article was originally published by WIRED UK
