Abstract: A quantum key distribution system may include a transceiver including a state randomizer to impart a random state transformation to one or more qubits of a generated faint pulse and a quantum bit encoder to reflect the faint pulse back to the transceiver with one or more encoded bits. The transceiver may receive a return pulse through the communication channel, where the state randomizer reverses the random state transformation. The transceiver may include three or more detectors to measure the return pulse at time-gated timeslots associated with possible paths of the return pulse. Reception of the faint pulse from the quantum bit encoder as the return pulse triggers a detector in a first known subset of the detectors, while reception of a faked-state pulse from a third party as the return pulse results in a non-zero probability of triggering of a detector in a second known subset of the detectors.

Abstract: A quantum key distribution system may include a transceiver including a state randomizer to impart a random state transformation to one or more qubits of a generated faint pulse and a quantum bit encoder to reflect the faint pulse back to the transceiver with one or more encoded bits. The transceiver may receive a return pulse through the communication channel, where the state randomizer reverses the random state transformation. The transceiver may include three or more detectors to measure the return pulse at time-gated timeslots associated with possible paths of the return pulse. Reception of the faint pulse from the quantum bit encoder as the return pulse triggers a detector in a first known subset of the detectors, while reception of a faked-state pulse from a third party as the return pulse results in a non-zero probability of triggering of a detector in a second known subset of the detectors.