Method of operation of a quantum key controller

A quantum key distribution system, comprising:

• a plurality of trusted nodes, each having a quantum key controller with at least a quantum transmitter or a quantum receiver;
• a first endpoint trusted node and a second endpoint trusted node, of the plurality of trusted nodes, to exchange a first public key with each other;
• the first endpoint trusted node to transmit a first quantum key over a first quantum channel to a first middle-trusted node, that is one of one or more middle-trusted nodes of the plurality of trusted nodes between the first endpoint trusted node and the second endpoint trusted node;
• the first endpoint trusted node to combine a first key with the first public key to form a once encrypted key, encrypt the once encrypted key with a quantum enhanced key based on the first quantum key to form a twice encrypted key, and transmit the twice encrypted key over a network to the first middle-trusted node;
• each of the one or more middle-trusted nodes to receive a quantum key over a quantum channel from a preceding trusted node and transmit a further quantum key over a further quantum channel to a following trusted node, receive a corresponding twice encrypted key over the network from the preceding trusted node, decrypt the corresponding twice encrypted key with the quantum key to form the once encrypted key, re-encrypt the once encrypted key with the further quantum key to form a further twice encrypted key, and transmit the further twice encrypted key over the network to the following trusted node;
• and
• the second endpoint trusted node to receive the further quantum key over the further quantum channel from a final one of the middle-trusted nodes, receive the twice encrypted key over the network from the final middle-trusted node, decrypt the twice encrypted key with the further quantum key to form the once encrypted key, and extract, using the first public key, the first key from the once encrypted key, so that the first endpoint trusted node and the second endpoint trusted node each has the first key.

A component for a quantum communication system, comprising:

• a trusted node, configurable as each of a first endpoint trusted node, a middle-trusted node, and a second endpoint trusted node, and having a quantum key controller, wherein a plurality of such trusted nodes configured as the first endpoint trusted node, the second endpoint trusted node and one or more middle-trusted nodes are able to form the quantum communication system;
• the quantum key controller, with the trusted node as the first endpoint trusted node, to direct a quantum transmitter to exchange a first quantum key between the trusted node and a trusted node that succeeds the first endpoint trusted node, to encrypt data comprising a first key using the first quantum key and transmit the data comprising the first key encrypted using the first quantum key to the trusted node that succeeds the first endpoint trusted node over a network;
• the quantum key controller, with the trusted node as the middle-trusted node, to direct a quantum receiver to exchange a preceding quantum key with a trusted node that precedes the middle-trusted node and direct a quantum transmitter module to exchange a succeeding quantum key with a trusted node that succeeds the middle-trusted node, to decrypt, using the preceding quantum key, the data comprising the first key encrypted using the preceding quantum key, re-encrypt, using the succeeding quantum key, the data comprising the first key and transmit the data comprising the first key encrypted using the succeeding quantum key to a trusted node that succeeds the middle-trusted node over the network;
• and
• the quantum key controller, with the trusted node as the second endpoint trusted node, to direct a quantum receiver to exchange a second quantum key with a trusted node that precedes the second endpoint trusted node, to receive from the network and decrypt, using the second quantum key, the data comprising the first key encrypted using the second quantum key and obtain the first key, so that the first endpoint trusted node and the second endpoint trusted node each have the first key.