Abstract: A method of operating a quantum key distribution (QKD) system including using a quantum random number generator (QRNG) to generate a random number string (RNS), and storing the RNS; providing the RNS to a first cryptographically secure pseudo-random number generator (CSPRNG) which uses random numbers of the RNS as seeds to generate respective first strings of pseudo-random numbers; using the first strings of pseudo-random numbers to encode photons or pulses transmitted by a transmitter of the QKD system; after a predetermined delay, providing the stored RNS to a second CSPRNG which uses random numbers of the RNS as seeds to generate respective second strings of pseudo-random numbers, the second CSPRNG identically configured to the first CSPRNG; using the second strings of pseudo-random numbers, together with information regarding encoded photons or pulses received by a receiver of the QKD system, to agree secure keys between the transmitter and the receiver.

Abstract: A method of scheduling encryption key delivery communication sessions in a satellite quantum key distribution system comprising a constellation of one or more satellites and a plurality of user ground stations comprises producing a list of user ground stations requiring encryption keys. For each satellite of the constellation of satellites, determining a region of the earths surface within which the satellite can carry out encryption key delivery communication sessions to user ground stations using a quantum optical communications link during a scheduling period. Obtaining a cloud cover map. Comparing the locations of the listed user ground stations, the determined regions of the earths surface for the constellation of satellites, and the cloud cover map, to identify listed user ground stations to which encryption key delivery can be carried out by the constellation of satellites during the scheduling period.

Abstract: Method(s), system(s), apparatus are provided for storing one or more data item(s) in a quantum-safe (QS) network. The QS network comprising one or more QS server(s) and a repository for storing and accessing said data item(s). Each QS server comprising a hardware security module (HSM) for storing an identical set of quantum distributed (QD) keys. The identical set of QD keys having been distributed to each of said QS server(s) in a quantum-safe manner. The QS server(s) are configured to communicate securely with each other and the repository using one or more available QD keys from the identical set of QD keys. A QS server performs generating a quantum reference (QREF) locator based on input data associated with a data item for storage and an available QD key selected from the set of QD keys, and sending the QREF locator along with the data item encrypted with the available QD key to the repository for storage.

Abstract: Methods, apparatus, and systems are provided for performing a quantum key distribution (QKD) protocol between a first device, a second device, and an intermediary device. The intermediary device transmitting: a first secret symbol string over a first quantum channel to the first device; a first basis set over a first communication channel to the first device. The intermediary device; a second secret symbol string over a second quantum channel to the second device; a second basis set over a second communication channel to the second device. The intermediary device generating a third symbol string based on combining the first and second secret symbol strings and transmitting to the second device, via the second communication channel, data representative of the third symbol string.

Abstract: A method of operating a quantum key distribution (QKD) system including using a quantum random number generator (QRNG) to generate a random number string (RNS), and storing the RNS; providing the RNS to a first cryptographically secure pseudo-random number generator (CSPRNG) which uses random numbers of the RNS as seeds to generate respective first strings of pseudo-random numbers; using the first strings of pseudo-random numbers to encode photons or pulses transmitted by a transmitter of the QKD system; after a predetermined delay, providing the stored RNS to a second CSPRNG which uses random numbers of the RNS as seeds to generate respective second strings of pseudo-random numbers, the second CSPRNG identically configured to the first CSPRNG; using the second strings of pseudo-random numbers, together with information regarding encoded photons or pulses received by a receiver of the QKD system, to agree secure keys between the transmitter and the receiver.

Abstract: Method(s), system(s), apparatus are provided for storing one or more data item(s) in a quantum-safe (QS) network. The QS network comprising one or more QS server(s) and a repository for storing and accessing said data item(s). Each QS server comprising a hardware security module (HSM) for storing an identical set of quantum distributed (QD) keys. The identical set of QD keys having been distributed to each of said QS server(s) in a quantum-safe manner. The QS server(s) are configured to communicate securely with each other and the repository using one or more available QD keys from the identical set of QD keys. A QS server performs generating a quantum reference (QREF) locator based on input data associated with a data item for storage and an available QD key selected from the set of QD keys, and sending the QREF locator along with the data item encrypted with the available QD key to the repository for storage.

Abstract: Methods, apparatus, and systems are provided for performing a quantum key distribution (QKD) protocol between a first device, a second device, and an intermediary device. The intermediary device transmitting: a first secret symbol string over a first quantum channel to the first device; a first basis set over a first communication channel to the first device. The intermediary device; a second secret symbol string over a second quantum channel to the second device; a second basis set over a second communication channel to the second device. The intermediary device generating a third symbol string based on combining the first and second secret symbol strings and transmitting to the second device, via the second communication channel, data representative of the third symbol string.

Abstract: A method of scheduling and managing key data in a satellite quantum key distribution system comprising a constellation of one or more satellites and a plurality of user ground stations.

Abstract: A method of scheduling encryption key delivery communication sessions in a satellite quantum key distribution system comprising a constellation of one or more satellites and a plurality of user ground stations comprises producing a list of user ground stations requiring encryption keys. For each satellite of the constellation of satellites, determining a region of the earths surface within which the satellite can carry out encryption key delivery communication sessions to user ground stations using a quantum optical communications link during a scheduling period. Obtaining a cloud cover map. Comparing the locations of the listed user ground stations, the determined regions of the earths surface for the constellation of satellites, and the cloud cover map, to identify listed user ground stations to which encryption key delivery can be carried out by the constellation of satellites during the scheduling period.