An improved coherent communication scheme is provided. The coherent communication scheme encodes both classical and quantum information simultaneously using isolated groups of states: classical information is represented by different groups and can be decoded deterministically; and quantum information is represented by highly overlapped states within the same group, thus guaranteeing security. Decoding includes projecting the detection results at the receiver to one of the distinguishable encoding groups first, which allows the classical information to be read out, and then generating a quantum key from the residual randomness. This communications scheme enables simultaneous classical communication and QKD over the same communication channel using the same transmitter and receiver, opening the door to operate QKD in the background of classical communication and at negligible costs.

This application provide quantum key distribution methods, devices, and storage media. In an implementation, a method comprises: determining, based on a first mapping, a first quantum key of N first quantum keys corresponding to an i.sup.th node on a target routing path; determining, based on a second mapping, a second quantum key of N second quantum keys corresponding to the i.sup.th node; and generating, by the i.sup.th node based on the first quantum key corresponding to the i.sup.th node and the second quantum key corresponding to the i.sup.th node, a third quantum key corresponding to the i.sup.th node on the target routing path.

A trusted node, for quantum key distribution, has a quantum key engine, a quantum key controller and a trusted node controller. The quantum key engine exchanges quantum keys. The quantum key controller directs encryption and decryption. The trusted node controller directs the quantum key controller and the quantum key engine, and has no direct access to keys and data protected by the system, including unencrypted quantum keys.

An example operation may include one or more of receiving a chain of blocks from a blockchain comprising a directed acyclic graph (DAG) format in which blocks are independently hash-linked to multiple blocks, identifying temporal relationships between blocks in the chain of blocks based on a structure of the chain of blocks in the DAG format, determining a sequential linear order of the chain of blocks in the DAG format based on the identified temporal relationships, and storing the sequential linear order of the chain of blocks.

A method includes identifying connections between plural components of a time sensitive network (TSN) that are interconnected via a predetermined connection plan. The method also includes determining quantum key distribution (QKD) information of the components. Also, the method further includes scheduling flows for the TSN based on the QKD information of the components.

A quantum communication system for encrypting communication includes a processor configured to receive an encryption request from a mobile device. The mobile device determines a first encryption key from the mobile device. A quantum random number generator generates a second encryption key using quantum mechanics. The processor transmits the second encryption key to the mobile device. The mobile device implements a digital XOR logic gate configured to perform an XOR operation on the first encryption key and the second encryption key to generate a third encryption key.

A communication system is provided that includes a first quantum key distribution device and a communication device. The first quantum key distribution device is configured to be coupled to a second quantum key distribution device over a quantum channel and to generate a quantum key based on a quantum state transmitted along the quantum channel. The communication device is communicatively connected to the first quantum key distribution device within a network. The communication device is configured to receive the quantum key from the first quantum key distribution device and transmit the quantum key to an end device in the network via a classical link to enable the end device to use the quantum key for encrypting and/or decrypting messages communicated through the network.

Described is a method of setting up a plurality of quantum communications links, forming a quantum network providing provably secure communications and internet services over intercontinental distances without requiring direct line of sight communication or the intermediate use of the entanglement resource of satellites. Also described is a quantum communicator device for use in this method. Two or more quantum memory units are disposed at a first location, an entangled link is set up between at least two of the quantum memory units, at least one of the quantum memory units sharing in the entangled link is physically transported to a second location. The quantum communicator device comprises communications nodes, an optical interface to set up entanglement to other devices and storage nodes, each node in the form of a quantum memory unit capable of storing quantum information for a desired length of time, i.e. weeks or longer.

Quantum network devices, systems, and methods are provided to enable long-distance transmission of quantum bits (qubits) for applications such as Quantum Key Distribution (QKD), entanglement distribution, and other quantum communication applications. Such systems and methods provide for separately storing first, second, third, and fourth photons, wherein the first and second photons and the third and fourth photons are respective first and second entangled photon pairs, triggering a synchronized retrieval of the stored first, second, third, and fourth photons such that the first photon is propagated to a first node, the second and third photons are propagated to a second node, and the fourth photon is propagated to a third node, and creating a new entangled pair comprising the first and fourth photons at the first and third nodes to transmit quantum information.

A method for a quantum key distribution from a first target node to a second target node across a network via an entanglement-based protocol, including the following steps: transferring entangled particles from a load node to the first target node and to at least one intermediate node; generating a quantum key with the entangled particles transferred to the first target node and the at least one intermediate node; transmitting the quantum key to the second target node on a first path located on the network with a stage of secure quantum key transmission agreement starting from the at least one intermediate node by encrypting intervals of binary nodes with pre-shared quantum keys; and providing a secure communication with the quantum keys between the first target node and the second target node on a second path located on the network.