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US 7,889,868 B2Granted
Quantum key distribution system
AssigneeVerizon Business Global LLC
InventorsGlenn A. Wellbrock, Tiejun J. Xia, David Z. Chen
Life of this patent
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Abstract
A method is provided for distributing quantum cryptographic keys. The method includes receiving a first quantum signal from an initial quantum key generating transmitter. Following correspondence with the initial quantum key generating transmitter, a first quantum key is generated. A second quantum signal is transmitted to a recipient quantum key generating transmitter. Following correspondence with the recipient quantum key generating receiver, a second quantum key is generated. The first quantum key is encoded using the second quantum key. The encoded first quantum key is transmitted to the recipient quantum key generating receiver using the second quantum key.
Claims17
A method for distributing quantum cryptographic keys, comprising:
- receiving, at an intermediate key forwarding device, a first quantum signal from an initial quantum key generating transmitter;
- corresponding, by the intermediate key forwarding device, with the initial quantum key generating transmitter to generate a first quantum key;
- transmitting, by the intermediate key forwarding device, a second quantum signal to a recipient quantum key generating transmitter;
- corresponding, by the intermediate key forwarding device, with the recipient quantum key generating receiver to generate a second quantum key;
- encoding, by the intermediate key forwarding device, the first quantum key using the second quantum key;
- and
- transmitting, by the intermediate key forwarding device, the encoded first quantum key to the recipient quantum key generating receiver,
- wherein receiving the first quantum signal and corresponding with the initial quantum key generating transmitter each occur via a single combined channel that includes the first quantum signal and a public data signal alternating in a time shared manner, and
- wherein receiving the first quantum signal and corresponding with the initial quantum key generating transmitter further comprises:
- splitting the single combined channel signals into a first split signal and a second split signal;
- applying a low attenuation to the first split signal when the first split signal includes the first quantum signal;
- applying a high attenuation to the first split signal when the second split signal includes the public data signal;
- receiving the first split signal at an intermediate quantum key generating receiver;
- receiving the second split signal at an intermediate quantum key public data receiver;
- applying a high attenuation prior to splitting the single combined channel signals when the first split signal includes the first quantum signal;
- and
- applying a low attenuation prior to splitting the signal combined channel when the first split signal includes the first public data signal.
14 more elements
A system for distributing a quantum cryptographic key, comprising:
- a quantum key generating transmitter configured to transmit a first quantum signal over a first network span, wherein the first network span includes a single combined channel that includes the first quantum signal and a public data signal alternating in a time shared manner;
- an intermediate key forwarding device comprising:
- a splitter to receive a signal from the quantum key generating transmitter, via the single combined channel, and split the received signal into a first split signal and a second split signal;
- an intermediate quantum key generating receiver to receive the first split signal;
- a first attenuating device to apply a low attenuation to the first split signal when the first split signal includes the first quantum signal,
- wherein the first attenuating device is configured to apply a high attenuation to the first split signal when the second split signal includes the public data signal;
- a second attenuating device to apply a high attenuation prior to splitting the single combined channel signals when the first split signal includes the first quantum signal and a low attenuation prior to splitting the single combined channel signals when the first split signal includes the first public data signal;
- and
- a public data receiver to receive the second split signal,
- wherein the intermediate key forwarding device is configured to correspond with the quantum key generating transmitter via the single combined channel, to generate a first quantum key based on the first quantum signal, and transmit a second quantum signal over a second network span;
- and
- a second quantum key generating receiver configured to receive the second quantum signal from the intermediate key forwarding device, and correspond with the intermediate key forwarding device to generate a second quantum key based on the second quantum signal,
- wherein the intermediate key forwarding device is configured to encode the first quantum key based on the second quantum key and transmit the encoded first quantum key to the second quantum key generating receiver, and
- wherein the second quantum key generating receiver is configured to receive and decode the encoded first quantum key.
11 more elements
A device for distributing a quantum key over a long haul network, comprising:
- an intermediate key generating receiver configured to receive a first set of random quantum bits from an initial key generating transmitter via a single combined channel that includes the first set of random quantum bits and a public data signal alternating in a time shared manner, wherein the single combined channel is configured to receive the random quantum bits from the initial key generating transmitter in an optical supervisory channel included therein,
- wherein the intermediate key generating receiver is configured to communicate with the initial key generating transmitter via the single combined channel to generate a first key based on the first set of random quantum bits,
- wherein the intermediate key generating receiver is further configured to:
- split the first set of random quantum bits and the public data signal from the single combined channel signals into a first split signal and a second split signal;
- apply a low attenuation to the first split signal when the first split signal includes the first set of random quantum bits;
- apply a high attenuation to the first split signal when the second split signal includes the public data signal;
- receive the first split signal at an intermediate quantum key generating receiver;
- receive the second split signal at an intermediate quantum key public data receiver;
- apply a high attenuation prior to splitting the single combined channel signals when the first split signal includes the first set of random quantum bits;
- and
- apply a low attenuation prior to splitting the single combined channel when the first split signal includes the public data signal;
- and
- an intermediate key generating transmitter configured to transmit a second set of random quantum bits to a recipient key generating receiver, communicate with the recipient key generating receiver to generate a second key based on the second set of random quantum bits, encode the first key using the second key, and transmit the encoded first key to the recipient key generating receiver using the second key.
10 more elements
Dependencies are inferred from the claim text.