Patent attributes
A method of distributing a quantum key from a sender to a recipient. The recipient generates a pulse having multiple photons; splits the pulse into first and second sub-pulses; phase modulates the first sub-pulse with a secret key; and transmits both the phase-modulated first sub-pulse and the second sub-pulse to the sender. The sender receives the phase-modulated first sub-pulse and the second sub-pulse from the recipient; encodes a quantum key bit into one of the sub-pulses received from the recipient; and transmits both the phase-modulated first sub-pulse and the second sub-pulse back to the recipient. Then, the recipient receives the phase-modulated first sub-pulse and the second sub-pulse from the sender; phase modulates the second sub-pulse with the secret key; combines the phase-modulated first sub-pulse and the phase-modulated second sub-pulse to produce a composite pulse; and processes the composite pulse in an attempt to detect the quantum key bit.
