Quantum Key Distribution (QKD) is a method for secure communication using quantum mechanics principles. It involves sending individual photons through a quantum channel, where each photon’s polarization (vertical/horizontal or plus/minus 45 degrees) represents a binary value (0 or 1).
Alice, the sender, randomly chooses both the polarization and value for each photon. Bob, the receiver, randomly chooses a polarization when detecting photons. If he matches Alice’s polarization, he measures the correct value. Alice then informs Bob of the correct polarization for each photon, allowing them to discard mismatched measurements.
The remaining correct measurements form the shared encryption key. Eavesdroppers (Eve) attempting to intercept the transmission must guess values, introducing errors detectable by Alice and Bob. QKD provides secure communication with high speed (312 million values per second) and real-time error detection.
Source: https://www.nist.gov/news-events/news/2004/04/background-quantum-key-distribution
Keywords: photon, encryption, channel, Eve, Alice, Bob, digital, value, key, mode, orientation
