China Bounced an 'Unhackable' Quantum Signal Between Cities
Quantum cryptography could help lay the groundwork for tomorrow's quantum networks but it faces a significant physical hurdle: entangled photons are hard to transmit long distances. Researchers from the Chinese Academy of Sciences may have the solution. You just have to send the photons 745 miles into space. "It's a challenging task," physicist Chao-Yang Lu, told Wired. "It's like you have to clearly see a human hair from 300 meters away." The team hopes that their successful experiment could pave the way for more secure encryption systems. In theory, you'd first encode an encryption key based on the characteristics of a photon stream and send that to your message's recipient. You'd then encrypt your message with that key and send it on as well. If someone tries to intercept, decode or even observe the key while in transit, the laws of quantum mechanics dictate that the key itself would change. So even if they intercepted the key and the message, both would be useless.