A key distribution method for secure optical network based on CV-QKD

Abstract

The present invention discloses a key distribution method for a secure optical network based on CV‑QKD. Among them, after the secure optical network network management allocates the channel paths of the communicating parties, it first calculates the transmission distance of the communication path and compares it with the specific distance criterion of the secure optical network, so as to judge which quantum state detection method can improve the security key rate when the communicating parties are performing continuous variable quantum key distribution. Finally, the judgment result is sent to the communicating parties in the form of instructions, so that the communicating parties can choose the optimal detection method. The present invention utilizes the characteristics of balanced heterodyne detection in the continuous variable quantum key distribution system that is suitable for short-distance quantum key distribution and balanced homodyne detection that is suitable for long-distance quantum key distribution, thereby realizing the improvement of the key rate of the secure optical network. At the same time, the optimization method adopted by the present invention does not require changing the network layout or the routing algorithm, and has better practicality.

Description

Technical Field

[0001] The present invention relates to the field of quantum key distribution optical networks, and in particular to a key distribution method for a secure optical network based on continuous variable quantum key distribution (CV-QKD), which can improve the security key rate. Background Art

[0002] Based on the quantum non-cloning principle and Heisenberg's uncertainty principle, quantum communication has been proven to have unconditional theoretical security. As modern network information security has received more and more attention, quantum communication has gradually become a network security protection method. Compared with the current high-speed classical communication, under the one-time encryption method, the continuous variable quantum key distribution security key rate is far from meeting the network communication encryption requirements.

[0003] At present, the main methods to improve the key rate of secure optical networks based on continuous variable quantum key distribution are error correction algorithms with high error correction capabilities at the receiving end and the use of ultra-low noise equipment. Among them, ultra-low noise communication equipment is not suitable for the commercialization of continuous variable quantum key distribution secure optical networks, and there is still room for further improvement in error correction algorithms with high error correction capabilities. Summary of the invention

[0004] The purpose of the present invention is to address the deficiencies in the above-mentioned background technology, and to propose a new key distribution method that can improve the security key rate in a secure optical network based on the upper bound of the von Neumann mutual information given by the Holevo bound and the amount of information obtained by the eavesdropper during a collective attack in quantum key distribution. The method does not require changing the topological structure and path planning algorithm in the original optical network, and improves the compatibility and practicality of the continuous variable quantum key distribution system in the optical network.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A key distribution method for a secure optical network based on CV-QKD, wherein each node in the secure optical network based on CV-QKD includes a balanced homodyne detector and a balanced heterodyne detector, and each secure optical network has an independent distance criterion; the method comprises the following steps:

[0007] (1) After receiving the link establishment request from the communication initiator, the network management performs path planning and calculates the signal transmission distance of the planned path;

[0008] (2) Compare the signal transmission distance calculated in step (1) with the distance criterion, so as to determine the detection method to be used by both parties in the quantum key distribution communication;

[0009] (3) The network manager opens the link by issuing instructions, and sends the link establishment notification and the required detection method to the two nodes where communication is established, completing the continuous variable quantum key distribution.

[0010] Furthermore, in step (2), the distance criterion is obtained after testing the secure optical network using homodyne detection and heterodyne detection. When the signal transmission distance obtained in step (1) is greater than the distance criterion, the key rate obtained by balanced homodyne detection is higher, and the detection method adopts balanced homodyne detection; when the signal transmission distance obtained in step (1) is not greater than the distance criterion, the key rate obtained by balanced heterodyne detection is higher, and the detection method adopts balanced heterodyne detection.

[0011] A key distribution method for a secure optical network based on CV-QKD, wherein each node in the secure optical network based on CV-QKD includes a balanced homodyne detector and a balanced heterodyne detector, and each secure optical network has an independent distance criterion; the method comprises the following steps:

[0012] (1) The communication initiator sends a request to the network manager to establish a communication link with another node;

[0013] (2) The network management determines whether the initiator can establish a communication link with the requested node based on the current status of each line and node in the optical network;

[0014] (3) If the conditions for establishing a communication link are not met, wait; if the link can be established, perform path planning and calculate the one-way signal transmission distance of the signal under the path;

[0015] (4) Compare the signal transmission distance with the distance criterion and select a quantum signal detection method suitable for the transmission distance; if the transmission distance is greater than the distance criterion, use a balanced homodyne detection method; if the transmission distance is less than or equal to the distance criterion, use a balanced heterodyne detection method;

[0016] (5) The network manager opens the communication link and issues instructions;

[0017] (6) The communicating parties select the quantum signal detection method according to the instructions issued and start continuous variable quantum key distribution.

[0018] The beneficial effects of the present invention are:

[0019] 1. The present invention utilizes the planning of the communication paths of the two communicating parties by the optical network network management, as well as the relationship between different signal transmission distances and quantum signal detection methods, so that the two communicating parties can select the appropriate quantum signal detection method and improve the quantum security key rate between the two communicating parties. This method does not require changing the topological structure and path planning algorithm in the original optical network, improves the compatibility and practicality of the continuous variable quantum key distribution system in the optical network, and has better application value.

[0020] 2. The method of the present invention does not conflict with the existing error correction algorithm with high error correction capability, and the two can complement each other, thereby further improving the security key rate of the secure optical network.

[0021] In summary, the present invention utilizes the characteristics of balanced heterodyne detection in the continuous variable quantum key distribution system that is suitable for short-distance quantum key distribution and balanced homodyne detection that is suitable for long-distance quantum key distribution, thereby improving the key rate of the secure optical network. At the same time, the optimization method adopted by the present invention does not require changing the network layout or the routing algorithm, and has better practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flow chart of the method of the present invention.

[0023] Figure 2 It is a schematic diagram of the principle of a specific embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0025] A key distribution method for a secure optical network based on CV-QKD, which allocates channel paths between communicating parties through secure optical network management, then calculates the transmission distance of the communication path, and compares it with the specific distance criterion of the secure optical network, so as to determine which quantum state detection method can improve the security key rate when the two communicating parties are performing continuous variable quantum key distribution, and finally sends the judgment result to the two communicating parties through the way of issuing instructions, so that the two communicating parties can choose the optimal detection method. Figure 1 As shown, the main implementation steps are as follows:

[0026] (1) The communication initiator sends a request to the network manager to establish a communication link with another node;

[0027] (2) The network management establishes a communication link based on the current optical network link status through a path planning algorithm;

[0028] (3) The network manager calculates the signal transmission distance of the link between the two communicating parties and compares it with the distance criterion in the optical network to select the appropriate quantum signal detection method;

[0029] (4) The network management sends the link establishment completion and judgment results to the communicating parties;

[0030] (5) The communicating parties select the appropriate quantum signal detection method according to the instructions issued by the network manager, start continuous variable quantum key distribution, and obtain the quantum security key.

[0031] Among them, the communication initiator described in step (1) can only conduct quantum secure confidential communication with one network node at the same time, and when in the communication state, it can no longer initiate a communication application to the network manager.

[0032] Wherein, when performing step (2), if the other network node that the initiator requires to communicate is in a quantum secure communication state, a communication link cannot be established with it at present. There are at least two or more channels between the adjacent nodes. When the idle link in the network cannot establish a communication link between the two communicating parties, path planning cannot be performed.

[0033] Wherein, when performing steps (3) and (4), the distance criterion is measured when the optical network is established. When the signal transmission distance exceeds the distance criterion, a balanced homodyne detection method is selected for quantum signal detection; when the signal transmission distance is less than or equal to the distance criterion, a balanced heterodyne detection method is selected.

[0034] Using this method, the maximum quantum secure key rate can be obtained.

[0035] This method proposes a convenient and reliable method to improve the security key rate of a secure optical network based on continuous variable quantum key distribution system, based on the characteristics of the secure optical network itself and the requirements for the detection method. This method uses the optical network network management to plan the communication paths of the two communicating parties, and through the calculation and judgment of the signal transmission distance, the two communicating parties can choose the appropriate quantum signal detection method, thereby improving the quantum security key rate between the two communicating parties.

[0036] The following takes the secure optical network structure based on continuous variable quantum key distribution as an example to illustrate the detailed implementation process of this method.

[0037] Figure 2The figure shows the structure of a four-node quantum secure communication optical network. Node A, Node B, Node C and Node D are all communication nodes in the optical network. Node A and Node C perform quantum secure confidential communication. All four nodes have modules for preparing Gaussian modulated quantum states, balanced homodyne detection modules and balanced heterodyne detection modules. All four nodes can perform separate continuous variable quantum key distribution ((A,B), (A,C), (A,D), (B,A), (B,C), (B,D), (C,A), (C,B), (C,D), (D,A), (D,B), (D,C)) in pairs, and can all be used as transmitters and receivers for continuous variable quantum key distribution. Here L1 = 1km, L2 = 2km, L3 = 3km, L4 = 4km, L5 = 5km, L6 = 6km, and the distance criterion is 6km. When the signal transmission distance exceeds 6km, the security key rate obtained by homodyne detection is higher; when the transmission distance is less than or equal to 6km, the security key rate obtained by heterodyne detection is higher. The specific process is as follows:

[0038] Step 1: When node A is not in the state of continuous variable quantum key distribution, node A is the initiator of communication. Node A first initiates a request to the four-node quantum secure optical network network manager to establish a link with node C.

[0039] Step 2: After receiving the request from node A, the network manager first checks the status of node C to determine whether node C is in the quantum key distribution state; if node C is in an idle state, without considering the link occupancy, the communication links between node A and node C are as follows: L5, L4→L3, L1→L2, L4→L6→L2, L1→L6→L3. Here, it is assumed that lines L5 and L6 are busy, and the path planning algorithm is the shortest path algorithm. The final planned path is L1→L2, and the total transmission distance of the signal is 3km, which is less than the 6km indicator of the criterion. Therefore, when performing quantum key distribution, nodes A and C use the balanced heterodyne detection method. When the path planning is completed and the detection method is determined, the network manager sends the path planning to the relevant nodes to open up the communication link, and sends the link establishment completion and detection method to nodes A and C.

[0040] Step 3: After nodes A and C receive the network management command, the receiver chooses to use balanced heterodyne detection to detect the Gaussian modulated quantum state signal in the continuous variable quantum key distribution, and then starts continuous variable quantum key distribution in the secure optical network.

[0041] This method uses the signal transmission distance between communication nodes in the network to select the continuous variable quantum key distribution detection method, thereby improving the security key rate of the continuous variable quantum key distribution system, and effectively improving the security communication rate of the secure optical network system. This method does not require changes to the original network topology, nor does it require modifications to the complex path planning algorithm. The implementation method relies on the existing more mature detection module, which has better practicality.

[0042] The above is only a preferred implementation of the present invention, but the protection scope of the present invention is not limited thereto. The patent of the present invention is applicable to a variety of scenarios, and any scenario in which the detection method is selected by the continuous variable quantum signal transmission distance is within the protection scope of the present invention. Within the technical scope disclosed by the present invention, any transformation or replacement that can be easily thought of by a technician familiar with the field should be covered within the protection scope of the present invention.

Claims

1. A key distribution method for a secure optical network based on CV-QKD, wherein each node in the secure optical network based on CV-QKD comprises a balanced homodyne detector and a balanced heterodyne detector; characterized in that: Each secure optical network has an independent distance criterion; the method comprises the following steps: (1) After receiving the link establishment request from the communication initiator, the network management performs path planning and calculates the signal transmission distance of the planned path; (2) comparing the signal transmission distance calculated in step (1) with the distance criterion, thereby determining the detection method to be used by both parties in the quantum key distribution communication; wherein the distance criterion is obtained after the secure optical network is tested using homodyne detection and heterodyne detection. When the signal transmission distance obtained in step (1) is greater than the distance criterion, the key rate obtained by balanced homodyne detection is higher, and the detection method adopts balanced homodyne detection; when the signal transmission distance obtained in step (1) is not greater than the distance criterion, the key rate obtained by balanced heterodyne detection is higher, and the detection method adopts balanced heterodyne detection; (3) The network manager opens the link by issuing instructions, and sends the link establishment notification and the required detection method to the two nodes where communication is established, completing the continuous variable quantum key distribution.

2. A key distribution method for a secure optical network based on CV-QKD, wherein each node in the secure optical network based on CV-QKD comprises a balanced homodyne detector and a balanced heterodyne detector; characterized in that: Each secure optical network has an independent distance criterion; the method comprises the following steps: (1) The communication initiator sends a request to the network manager to establish a communication link with another node; (2) The network management determines whether the initiator can establish a communication link with the requested node based on the current status of each line and node in the optical network; (3) If the conditions for establishing a communication link are not met, wait; if the link can be established, perform path planning and calculate the one-way signal transmission distance of the signal under the path; (4) Compare the signal transmission distance with the distance criterion and select a quantum signal detection method suitable for the transmission distance; if the transmission distance is greater than the distance criterion, use a balanced homodyne detection method; if the transmission distance is less than or equal to the distance criterion, use a balanced heterodyne detection method; (5) The network manager opens the communication link and issues instructions; (6) The communicating parties select the quantum signal detection method according to the instructions issued and start continuous variable quantum key distribution.

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