Tamper-proof quantum communication now possible over 100km distance
What's the story
Researchers from the University of Science and Technology of China have made a major breakthrough in quantum encryption. They have successfully demonstrated a method to securely transmit information over more than 100km of optical fiber without relying on the trustworthiness of the equipment used. The team, led by Pan Jianwei, used individual rubidium atoms trapped in laser beams at two separate network nodes as the basis for their system.
Encryption technique
Device-independent quantum key distribution
The researchers made quantum links between the rubidium atoms using single light particles or photons. By comparing the states of these atoms at each end, they were able to generate identical strings of 0s and 1s. This served as a shared secret key for encryption. The unique aspect of this experiment is its reliance on device-independent quantum key distribution (DI-QKD), which guarantees security even in case of flawed or tampered devices.
Quantum protection
Closing the gap
The security of this method comes from the quantum-mechanical behavior of the entangled atoms, which protects against real-world vulnerabilities that have long plagued quantum communication systems. The researchers said in their paper that DI-QKD had only been demonstrated over short distances in a lab before. Their study, they added, helps to "close the gap between proof-of-principle experiments and real-world applications."