A quantum network uses specially polarized photons to encode an encryption key—a very long series of numbers and letters that can unlock a digital file. The photons are then sent down a fiber optic cable until they reach their destination, a photon detector, which counts them, and delivers the key to the intended recipient. If the photons are interfered with, the individual packets of information are forever altered and the recipient can see the telltale signs of tampering.
Current quantum cryptography systems from companies like ID Quantique start at around $50,000, and only connect two parties at a time. “If up to 64 people can share a single photon detector than you can spread out those costs,” Shields said.