Have you ever really looked at a photon? Part wave, part particle, all perfection. Yet they bring out the worst in some people, who bring out the worst in me. Let's start with the obvious: Photons, in all their quantum quintessence, can improve the security of internet connections.
Anybody can poke around standard-issue encryption keys undetected, but when the 1s and 0s are hooked into specific photons, that snooping triggers telltale state changes—revealing the presence of a hacker! Clever, right? What's less clever, and more maddening, are the ways companies overhype this style of quantum cryptography. They witter of an “unbreakable” and “unhackable” internet. I like quantum engineering projects as much as any midichlorian-blooded nerd, but a cybersecurity panacea? Au quantraire! The suggestion turns me into Schrödinger's sourpuss: neither angry nor disappointed but a superposition of both.
Only someone with the brains of a baryon—they are delightful but not smart—would claim quantum cryptography promises foolproof protection. Fancy tech is built by the skin-bags of water and viscera we call people, and people are not all perfection. Go ahead and give a highly trained someone a top-secret mission and a computer with a quantum-encrypted connection. Before long, they will turn lusty or sleepy or bored. They'll forget about software updates, share their passwords, and click links they should not. (Don't ask me how I know.) A canny hacker can wait for you to de-quantize your supersecret key and then steal it.
Quantum encryption is cool, but the marketers need to cool off. Photons have an intrinsic angular momentum of 1, and that's all the spin they need.
This article appears in the March issue. Subscribe now.