Qinetiq Limited

Vocalcomm Group, LLC

Qubitekk, Inc.

Richard Middleton Hicks

Brian Sinclair Lowans

Simon Robert Wiseman

Methods and apparatus for quantum key distribution are described, in particular including methods and networksarranged to improve and/or ensure the security of data transmitted thereby by (i) ensuring a certain level of loss within at least part of the network, (ii) placing a penultimate and an endpoint nodes in situated in a secure second enclave, (iii) analyzing a transmitted bit stream to ensure that it does not provide an unacceptable amount of information about the key that may be generated therefrom, and/or (iv) varying the order in which bits are used to generate a key.

Quantum key distribution

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.

Quantum cryptography apparatus

A method of establishing a quantum key for use between a first network node (QNode) and a second network node (QNode) in a network for carrying out quantum cryptography includes a key agreement step carried out by a third node (QNode) and the second node (QNode) and a subsequent authentication step carried out by the first and second nodes directly. As the key agreement step does not involve QNode, another key agreement step may be simultaneously performed by another pair of network nodes QNode, QNodeto agree a quantum key for use by network nodes QNodeand QNode. The invention allows respective quantum keys to be established between a network node and each of a set of other nodes more rapidly than is the case if each quantum key is established serially by key agreement and authentication steps.

Method of establishing a quantum key for use between network nodes

The present invention relates to an improved quantum key device for use in quantum key distribution, which device comprises a quantum detector unit for detecting a quantum signal and a plurality of logic units operably connected to the quantum detector unit wherein each logic unit is arranged to derive a separate quantum key from the quantum signal detected. In this way, a single quantum key distribution (QKD) receiver can generate separate quantum keys for separate users.

Quantum key device

Detection of items stored in a computer system such as computer code, data or information includes obtaining signatures characteristic of programs of interest such as steganographic programs. A signature is obtained by reading code from a program of interest. The code may consist of the first 500 bytes from a .DLL file taken from the programs' core steganographic kernel. This code is then the signature. The computer system compares the signature with files it holds, other than files on a prearranged exclusion list. If a signature is found to match data in a file, the filename, the finding of steganography in it, the file location and the matched signature are recorded by the computer system for output to its user.

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Malvern, United Kingdom

Richard Middleton Hicks