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US 8,855,316 B2Granted
Quantum cryptography apparatus
AssigneeQinetiq Limited
InventorsSimon Robert Wiseman, Brian Sinclair Lowans, Richard Middleton Hicks
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AssigneeQinetiq Limited
InventorsSimon Robert Wiseman, Brian Sinclair Lowans, Richard Middleton Hicks
Estimating the term…
The method involves exchange of a quantum signal between a first quantum node and a second quantum node as is usual in known quantum key distribution (QKD) scheme. The first quantum node communicates details of the quantum signal it sent or received with a first remote node. The first remote node thus has all the information to required to take the place of the first quantum node in the key agreement step with the second quantum node. The first quantum node may be arranged to transmit the quantum signal to the second quantum node, in which case the invention provides a distributed quantum transmitter with the control logic in the first remote node being distributed remotely from the actual quantum transmitter in the first quantum node. Communications between the first remote node and first quantum node may comprise or be protected by a quantum key derived by conventional QKD.
A method of quantum key distribution, comprising a quantum exchange step and a key agreement step that is subsequent to the quantum exchange step, wherein, in the quantum exchange step, a first quantum node and a second quantum node exchange a quantum signal over a quantum link between the first quantum node and the second quantum node and wherein the first quantum node communicates with a first remote node such that the first remote node has all of the information regarding at least one of the quantum signal transmitted or the quantum signal detected by the first quantum node necessary to agree a quantum key with the second quantum node, and the first remote node replaces the first quantum node in the subsequent key agreement step.
A serial quantum key distribution apparatus comprising a control QKD device linked in series, via at least one intermediate QKD device, with an endpoint QKD device wherein each of said QKD devices has at least one quantum transmitter or quantum receiver that exchanges a quantum signal with an adjacent QKD device, wherein each intermediate QKD device comprises a crypto-unit for communicating all of the information required to agree a quantum key regarding the quantum signal transmitted to or received from the subsequent QKD device in the series with a crypto-unit at the control QKD device and wherein the control QKD device agrees a quantum key with each of said intermediate QKD devices and the end point QKD device in the series in sequence.
An intermediate QKD device comprising
Dependencies are inferred from the claim text.