Method for key distribution using quantum cryptography
AssigneeBritish Telecommunications public limited company
InventorsSimon James Phoenix, Stephen Mark Barnett
Life of this patent
Estimating the term…
Abstract
In a communication system using quantum cryptography for the distribution of a key, two stations each independently modulate a single-photon signal. The single-photon signal is transmitted to the two stations from an external source, and passes through the stations in series. The signal subsequently passes onto a third station which detects the state of the signal, and compares it with the state of the signal as originally transmitted. This third station communicates the results of the comparison to the two stations, and the two stations establish a shared secret key for the subsequent encryption of traffic between the stations. Both the source of the single-photon signal and the single-photon detector may be combined in a transmitter station (Alice).
Claims13
A method of communication using quantum cryptography characterised in that two stations (Bob(1), Bob(2)) each independently modulate a single-photon signal transmitted from an external source to both the stations in series, the said signal subsequently passing on to a third station which detects the state of the signal, compares it with the state of the signal as originally transmitted, and communicates the results of the comparison to the two stations, the two stations thereby establishing a shared secret key for the subsequent encryption of traffic between the two stations.
A communications system comprising a communications network arranged to carry a quantum channel, a single-photon source arranged to output single-photon signals onto the network, at least two stations (Bob(1), Bob(2)) connected to the network and each including a modulator arranged to modulate in series the single-photon signal and a third station (Alice) including a single-photon detector arranged to detect the single-photon signal after its modulation by the at least two stations (Bob(1), Bob(2)), in use the third station (Alice) comparing the state of the single-photon signal as received with the state of the signal as originally transmitted and communicating the result of the comparison to the two stations, and the two stations establishing thereby a shared secret key.
Dependencies are inferred from the claim text.