Scheme allows sending lots of secret data with short decoding key
Researchers have built a modern-day Enigma machine that relies on the quirky laws of quantum mechanics instead of the rotors and levers of the famous World War II–era code machines. It’s the first experiment to show that it’s possible to send large amounts of secure quantum data protected by a much shorter secret key, the team reports August 12 in Physical Review A.
Encryption usually relies on a secret key that’s shared between two parties. The sender uses the key to scramble the message so it looks random to an outsider; the receiver uses the key to unscramble it. An eavesdropper who doesn’t have the key can’t read the garbled message.
Spies can use quantum mechanics to generate extremely secure keys that can’t be cracked by even the most powerful computers. Instead of a string of 1s and 0s, quantum keys use the spins of photons, tiny