Quantum key distribution method, device, equipment and medium based on quantum relay

Abstract

The present application provides a quantum key distribution method, apparatus, device and medium based on quantum relay, including: inputting the maximum entangled state of a first photon pair and the maximum entangled state of a second photon pair into a beam splitter to obtain a maximum entangled state of the photon number; converting the maximum entangled state of the photon number to obtain a maximum entangled state of the path; processing the maximum entangled state of the path to generate a quantum key, so as to solve the problem of low security of the current QKD link.

Description

Technical Field

[0001] The present application relates to the field of quantum communication technology, and in particular to a quantum key distribution method, apparatus, device and medium based on quantum relay. Background Art

[0002] Quantum Key Distribution (QKD) technology is one of the technologies for building quantum communication networks. It is a symmetric key distribution technology based on the principles of quantum mechanics that achieves "unconditional security" for both communicating parties.

[0003] In the existing technology, the quantum key distribution transmission distance of commercial QKD equipment is within 100KM, while the quantum key distribution of inter-city QKD equipment is mainly achieved through multi-hop trusted relay nodes. Trusted relay nodes need to use management means or classical encryption means to ensure the security of quantum key distribution. Since the encryption method of classical encryption means is simple and easy to crack, the inter-city QKD link key is easily leaked, resulting in the problem of low security of QKD link. Summary of the Invention

[0004] This application provides a quantum key distribution method, device, equipment and medium based on quantum relay to solve the problem of low security of the current QKD link.

[0005] In order to solve the above problems, the present application discloses a quantum key distribution method based on quantum relay, comprising:

[0006] Inputting the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain an entangled state with a maximum number of photons;

[0007] Converting the maximum photon number entangled state to obtain a path maximum entangled state;

[0008] The maximum entangled state of the path is processed to generate a quantum key.

[0009] Optionally, converting the photon maximum entangled state to obtain a path maximum entangled state includes:

[0010] Selecting a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled states with a maximum number of photons;

[0011] The first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons are input into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

[0012] Optionally, the path coding projection measurement device includes: a first path coding module and a second path coding module;

[0013] Inputting the first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons into a path coding projection measurement device for conversion to obtain the path maximum entangled state includes:

[0014] Inputting the first photon number maximum entangled state into the first path encoding module to obtain a first path maximum entangled state;

[0015] Inputting the second maximum photon number entangled state into the second path encoding module to obtain the second path maximum entangled state;

[0016] Screening the first path maximum entangled state and the second path maximum entangled state according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state;

[0017] The path maximum entangled state is generated according to the screened first path maximum entangled state and the screened second path maximum entangled state.

[0018] Optionally, processing the maximum entangled state of the path to generate a quantum key includes:

[0019] Performing a Bell inequality test on the maximum entangled state of the path to obtain a Bell inequality measurement result;

[0020] If the Bell inequality measurement result determines that the path maximum entangled state belongs to the maximum entangled state, a quantum key is generated according to the path maximum entangled state.

[0021] Optionally, the first photon pair includes: a first photon and a second photon, and the second photon pair includes: a third photon and a fourth photon;

[0022] Inputting the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain the entangled state with the maximum number of photons includes:

[0023] Inputting the first photon of the first photon pair and the third photon of the second photon pair into the beam splitter to obtain a maximum entangled state of the second photon and the fourth photon;

[0024] The maximum entangled state of the second photon and the fourth photon is used as the maximum photon number entangled state.

[0025] In order to solve the above problems, the present application also discloses a quantum key distribution device based on quantum relay, comprising:

[0026] A photon number entangled state module is used to input the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain a maximum photon number entangled state;

[0027] A conversion module for converting the maximum photon number entangled state to obtain a path maximum entangled state;

[0028] A generation module is used to process the maximum entangled state of the path to generate a quantum key.

[0029] Optionally, the conversion module includes:

[0030] A selection unit, configured to select a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled state with a maximum number of photons;

[0031] A conversion unit is used to input the first maximum photon number entangled state and the second maximum photon number entangled state into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

[0032] Optionally, the path coding projection measurement device includes: a first path coding module and a second path coding module;

[0033] The conversion unit includes:

[0034] A first path submodule, configured to input the first photon number maximum entangled state into the first path encoding module to obtain a first path maximum entangled state;

[0035] A second path submodule, configured to input the second photon number maximum entangled state into the second path encoding module to obtain a second path maximum entangled state;

[0036] a screening submodule, configured to screen the first path maximum entangled state and the second path maximum entangled state according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state;

[0037] A generating submodule is used to generate the path maximum entangled state according to the screened first path maximum entangled state and the screened second path maximum entangled state.

[0038] In order to solve the above problems, the present application also discloses a relay node deployment device, including:

[0039] memory; processor; and computer program;

[0040] The computer program is stored in the memory and is configured to be executed by the processor to implement the quantum key distribution method based on quantum relay.

[0041] In order to solve the above problems, the present application also discloses a computer-readable storage medium on which a computer program is stored. The computer program is executed by a processor to implement the quantum key distribution method based on quantum relay.

[0042] Compared with the prior art, this application has the following advantages:

[0043] The maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are input into the beam splitter to obtain the maximum entangled state of the photon number, the maximum entangled state of the photon number is converted to obtain the maximum entangled state of the path, and then the maximum entangled state of the path is processed to generate a quantum key. Since the maximum entangled state of the path is obtained by converting the maximum entangled state of the photon number, key distribution is achieved based on the maximum entangled state of the path, thereby constructing a longer-distance quantum key distribution, thus avoiding the use of an intermediate trusted relay, making quantum key distribution more secure and practical, thereby improving the security of the QKD link. Of course, any product implementing this application does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a flow chart of a quantum key distribution method based on quantum relay described in an embodiment of the present application;

[0045] Figure 2 This is a flow chart of a quantum key distribution method based on quantum relay described in an embodiment of the present application;

[0046] Figure 3 Schematic diagram of photon pair entanglement exchange in an embodiment of the present application;

[0047] Figure 4 This is a schematic diagram of a path coding projection measurement device according to an embodiment of the present application;

[0048] Figure 5 This is an example of a quantum key distribution application based on quantum relay described in an embodiment of the present application;

[0049] Figure 6 This is a schematic diagram of a quantum key distribution device based on quantum relay described in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0051] Reference Figure 1 , which shows a flow chart of a quantum key distribution method based on quantum relay according to an embodiment of the present application, specifically comprising the following steps:

[0052] Step 101: Input the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into a beam splitter to obtain an entangled state with a maximum number of photons.

[0053] In practical applications, the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair can be obtained in advance, where the maximum entangled state of the first photon pair refers to the maximum entangled state composed of two photons, that is, the number of photons in the entangled light fields of the two parties is in an entangled quantum state. When the number of photons measured by photon A is 0, the number of photons measured by photon B is 1; when the number of photons measured by photon A is 0, the number of photons measured by photon B is 1.

[0054] For example, the maximum entangled state of the first photon pair AB or the first photon pair CD can be calculated using the following formula:

[0055]

[0056] in, represents the maximum entangled state of the first photon pair AB, stands for the complex phase factor, which describes the phase of the quantum state and regulates its coherence, represents the measured value of photon A, represents the measured value of photon B, represents the vacuum state, that is, the state without photons, Represents the single-photon state, that is, the state where the number of photons is 1.

[0057] The maximum entangled state of the first photon pair CD can be calculated by the following formula:

[0058] in, represents the maximum entangled state of the first photon pair CD, stands for the complex phase factor, which describes the phase of the quantum state and regulates its coherence, represents the measured value of photon C, represents the measured value of photon D, represents the vacuum state, that is, the state without photons, Represents the single-photon state, that is, the state where the number of photons is 1.

[0059] Through the above formula, the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are obtained, and then the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are input into the beam splitter at the same time to obtain the maximum entangled state of the photon number. That is, the entangled state of the photon number of both parties at a longer distance is achieved through the entanglement exchange process.

[0060] Step 102: converting the photon maximum entangled state to obtain a path maximum entangled state.

[0061] In specific applications, path-coded projection measurement equipment can be used to convert the photon maximum entangled state into the path maximum entangled state.

[0062] The maximum path entanglement state refers to the quantum state of polarization entanglement of the photons of two parties. When the photon path of photon A is measured to be in the H direction, the photon path of photon B is measured to be in the V direction; when the photon path of photon A is measured to be in the V direction, the photon path of photon B is measured to be in the H direction.

[0063] Step 103: Process the maximum entangled state of the path to generate a quantum key.

[0064] In this embodiment, the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are input into a beam splitter to obtain a maximum entangled state of the photon number, the maximum entangled state of the photon number is converted to obtain a maximum entangled state of the path, and then the maximum entangled state of the path is processed to generate a quantum key. Since the maximum entangled state of the path is obtained by converting the maximum entangled state of the photon number, key distribution is realized based on the maximum entangled state of the path, thereby constructing a quantum key distribution over a longer distance, which avoids the use of an intermediate trusted relay, making quantum key distribution more secure and practical, thereby improving the security of the QKD link.

[0065] Reference Figure 2 , which shows a flow chart of a quantum key distribution method based on quantum relay according to an embodiment of the present application, specifically comprising the following steps:

[0066] Step 201: The maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are simultaneously input into a beam splitter to obtain an entangled state with a maximum number of photons.

[0067] Among them, the first photon pair includes: a first photon and a second photon, and the second photon pair includes: a third photon and a fourth photon. In specific applications, a resonant laser pulse can be used to read out the first photon and the third photon stored in the atomic system, and then the first photon and the third photon are simultaneously input into the beam splitter BS for photon number differentiation detection to obtain the maximum photon number entangled state.

[0068] by Figure 3 As an example, the process of photon pair entanglement exchange in the embodiment of the present application is described in detail. Figure 3 The system includes atomic system A, atomic system B, atomic system C, atomic system D, a beam splitter BS and a single-photon detector. Atomic system A and atomic system B constitute a first photon pair AB, and atomic system C and atomic system D constitute a second photon pair CD.

[0069] The first photon B in the first photon pair and the third photon C in the second photon pair are simultaneously input into the beam splitter to obtain the maximum entangled state of the second photon A and the fourth photon; the maximum entangled state of the second photon and the fourth photon is used as the maximum entangled state of the photon number, and then the maximum entangled state of the photon number is sent to the photon number detector through different paths for photon number resolved detection, and the different paths include: e path and f path.

[0070] The specific quantization evolution process adopts the following formula:

[0071]

[0072] Step 202: Select a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled states with a maximum number of photons.

[0073] Step 203: Input the first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

[0074] In practical applications, two entangled states with maximum photon number are randomly selected from the entangled states with maximum photon number, namely the first entangled state with maximum photon number and the second entangled state with maximum photon number. The first entangled state with maximum photon number and the second entangled state with maximum photon number are input into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

[0075] Step 203 includes the following sub-steps:

[0076] Sub-step 2031: inputting the first maximum photon number entangled state into the first path encoding module to obtain the first path maximum entangled state.

[0077] Sub-step 2032: Input the second maximum photon number entangled state into the second path encoding module to obtain the second path maximum entangled state.

[0078] Sub-step 2033: Screening the first path maximum entangled state and the second path maximum entangled state according to the detector screening rule to obtain the screened first path maximum entangled state and the screened second path maximum entangled state.

[0079] Sub-step 2034: Generate the path maximum entangled state according to the screened first path maximum entangled state and the screened second path maximum entangled state.

[0080] Among them, path coding projection measurement equipment, such as Figure 4 As shown, in Figure 4The path coding projection measurement device includes: a first path coding module 41 and a second path coding module 42, wherein the first path coding module includes: a first atomic system 1, a first phase modulator 3, a first beam splitter 4, a reflector 5, a second phase modulator 6, a second beam splitter 7, a first single-photon detector 8 and a second single-photon detector 9. The second path coding module includes: a second atomic system 2, a first phase modulator 3, a first beam splitter 4, a reflector 5, a second phase modulator 6, a second beam splitter 7, a first single-photon detector 8 and a second single-photon detector 9. The first atomic system 1 and the second atomic system are mutually entangled atomic systems, and a path entangled state is constructed using two pairs of atomic systems, wherein the first pair is the first photon number maximum entangled state A1B1, and the second pair is the second photon number maximum entangled state A2B2.

[0081] In practical applications, by adjusting the phases of the first phase modulator 3 and the second phase modulator 6, arbitrary projection measurement of single-bit path encoding can be achieved, thereby achieving Bell inequality violation measurement of path maximum entanglement and projection measurement of quantum key distribution. For example, taking the measurement basis of the BB84 protocol as an example, when the phases of the first phase modulator 3 and the second phase modulator 6 are both 0, the measurement basis is When the phase of the first phase modulator 3 is 0 and the phase of the second phase modulator 6 is π / 2, the measurement basis is .

[0082] Now with Figure 4 Taking φ as an example, a detailed description is given of the process of inputting the first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons into the path coding projection measurement device for conversion to obtain the path maximum entangled state, as follows:

[0083] The first photon number maximum entangled state A1B1 and the second photon number maximum entangled state A2B2 can be obtained by the following formulas.

[0084]

[0085] in, represents the maximum entangled state of the first beam A1B1, stands for the complex phase factor, which describes the phase of the quantum state and regulates its coherence, represents the measured value of photon A1, represents the measured value of photon B1, represents the vacuum state, that is, the state without photons, Represents the single-photon state, that is, the state where the number of photons is 1.

[0086]

[0087] in, represents the maximum entangled state of the second beam A2B2, stands for the complex phase factor, which describes the phase of the quantum state and regulates its coherence, represents the measured value of photon A2, represents the measured value of photon B2, represents the vacuum state, that is, the state without photons, Represents the single-photon state, that is, the state where the number of photons is 1.

[0088] The maximum entangled state of the first photon number is input into the first path encoding module, that is, the maximum entanglement of the first light beam is processed by the first phase modulator 3, the first beam splitter 4, the reflector 5, the second phase modulator 6, and the second beam splitter 7, and the maximum entangled state of the first path is obtained through the first single-photon detector 8 and the second single-photon detector 9.

[0089] The second maximum photon number entangled state is input into the second path encoding module, that is, the second light beam maximum entanglement is processed by the first phase modulator 3, the first beam splitter 4, the reflector 5, the second phase modulator 6, and the second beam splitter 7, and the second path maximum entangled state is obtained through the first single-photon detector 8 and the second single-photon detector 9.

[0090] The first path maximum entangled state and the second path maximum entangled state are screened according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state.

[0091] The detector screening rule includes any one of the following: there is only one detector response in the first path encoding module and the second path encoding module, or there are two detector responses in the first path encoding module and the second path encoding module.

[0092] The path maximum entangled state is generated according to the screened first path maximum entangled state and the screened second path maximum entangled state.

[0093] The first photon number maximum entangled state A1B1 and the second photon number maximum entangled state A2B2 are input to Figure 4 In the path-coded projection measurement device, the formula for the overall quantum state is:

[0094]

[0095] in, represents the overall quantum state, represents the maximum entangled state of the first path after processing by the first path encoding module, Represents the maximum entangled state of the second path after processing by the second path encoding module.

[0096] Assume that the detector screening rule is set such that only one single-photon detector responds in the first path encoding module and the second path encoding module, that is, among the above four quantum states, A1 and B1 have one single-photon state, and A2 and B2 have one single-photon state.

[0097] Item 1: ,First path encoding module (A1+A2):

[0098] A1 = (ground state); A2 = (ground state).

[0099] The first path encoding module excitation number = 0 (no detector response).

[0100] First path encoding module (B1+B2):

[0101] B1 = (excited state); B2 = (Excited state).

[0102] The number of excitations of the second path encoding module = 2 (two detector responses), and the first item does not meet the detector screening rule.

[0103] Item 2: , the first path encoding module (A1+A2):

[0104] A1 = (ground state); A2 = (excited state), the first path encoding module excitation number = 1 (one detector response).

[0105] Second path encoding module (B1+B2):

[0106] B1 = (excited state); B2 = (Ground state) The number of excitations of the second path encoding module = 1 (one detector response), and the second term satisfies the detector screening rule.

[0107] Item 3: , the first path encoding module (A1+A2):

[0108] A1 = (excited state); A2 = (Ground state) Number of excitations of the first path encoding module = 1 (one detector response).

[0109] Second path encoding module (B1+B2):

[0110] B1 = (ground state); B2 = (Excited state) The second path encodes the module excitation number = 1 (one detector response), and the third term satisfies the detector screening rule.

[0111] Item 4:

[0112] First path encoding module (A1+A2):

[0113] A1 = (excited state); A2 = (Excited state) Number of excitations in the first path encoding module = 2 (two detector responses).

[0114] Second path encoding module (B1+B2):

[0115] B1 = (ground state); B2 = (Ground state)

[0116] The second path encoding module excitation number = 0 (no detector response), and the fourth item does not meet the detector screening rule.

[0117] After the detector screening rules, only the second and third items meet the requirements of exactly one detector response in the first path encoding module and exactly one detector response in the second path encoding module.

[0118] After the above processing, the maximum entangled state quantum state of the two pairs of atomic systems for:

[0119]

[0120] The maximum entangled quantum state of the above path can be simplified as:

[0121] That is, the above formula generates the path maximum entangled state through the first path maximum entangled state and the second path maximum entangled state.

[0122] Step 204: Process the maximum entangled state of the path to generate a quantum key.

[0123] In a specific application, step 204 includes the following sub-steps:

[0124] Sub-step 2041: Perform a Bell inequality test on the maximum entangled state of the path to obtain a Bell inequality measurement result.

[0125] Sub-step 2042: If the Bell inequality measurement result determines that the path maximum entangled state belongs to the maximum entangled state, then generate a quantum key according to the path maximum entangled state.

[0126] Although the maximum entangled state of a path has been determined, random checks are still performed on the path's maximum entangled state using Bell's inequality to ensure that the violation of the Bell inequality is minimized. That is, the Bell inequality is used to determine whether the path's maximum entangled state is the maximum entangled state. If the Bell inequality check results indicate that the path's maximum entangled state is the maximum entangled state, the quantum key is generated based on the path's maximum entangled state. If the path's maximum entangled state is determined not to be the maximum entangled state, the set of path's maximum entangled states is discarded.

[0127] In certain applications, quantum keys generated based on the path-maximally entangled state can be implemented based on protocols such as BBM92. The BBM92 protocol is a quantum key distribution protocol. The specific steps are as follows:

[0128] 1. Generation and distribution of path-maximum entangled photon pairs: The entanglement source of the third party Charlie generates path-maximum entangled photon pairs, and then distributes the path-maximum entangled photon pairs to the sender Alice and the receiver Bob respectively.

[0129] 2. Measurement: Alice and Bob each measure the received photons using the same measurement method as the BB84 protocol. That is, in the polarization dimension of a single photon, they select two sets of non-orthogonal basis vectors (rectangular basis vectors and oblique basis vectors) and two orthogonal polarization states under each set of basis vectors (H polarization and V polarization under the rectangular basis vectors, and +45° polarization and -45° polarization under the oblique basis vectors) for measurement.

[0130] 3. Publish measurement basis vectors: Alice and Bob publish their respective measurement basis vectors through the classical communication channel.

[0131] 4. Screening key: Alice and Bob retain the same measurement results of the basis vector, which form the screened key.

[0132] 5. Data post-processing: Data post-processing is performed on the filtered key, including error correction and privacy amplification operations, to remove errors in the filtered key and information that may be obtained by the eavesdropper Eve, ultimately allowing Alice and Bob to share the same quantum key.

[0133] In this embodiment, the maximum photon number entangled state is input into the path coding projection measurement device for conversion to obtain the path maximum entangled state, thereby achieving the distribution of quantum keys over a long distance.

[0134] In order for those skilled in the art to better understand the technical solutions defined in this application, see Figure 5 This is an example of a quantum key distribution application based on quantum relay described in this application.

[0135] This embodiment includes: a transmitter Alice, a quantum relay node Charlie, and a receiver Bob. The quantum relay nodes are used to split the channel, and quantum storage technology is used to store quantum entangled photon pairs between short-distance nodes. Combined with cascaded entanglement exchange technology, quantum relay is used to construct a quantum entangled channel with the maximum number of entangled photons from the end user Alice to Bob.

[0136] Step 501: Through quantum storage and entanglement exchange technology, a long-distance transmitter and receiver can share the entangled state with the maximum number of photons.

[0137] Step 502: arbitrarily select two pairs of maximum photon number entangled states A1B1 and A2B2 from the maximum photon number entangled states, and convert the maximum light speed entangled states into path maximum entangled states.

[0138] Step 503: Randomly check the entangled photons in the maximum entangled state of the path to ensure that the Bell measurement results violate the maximum and ensure that the photons held by the legitimate users Alice and Bob are in the maximum entangled state.

[0139] Step 504: Perform independent random base measurements on Alice and Bob to obtain measurement results.

[0140] Step 505: Perform basis alignment and post-processing based on the measurement results to generate a quantum key.

[0141] Alice and Bob independently and randomly select a basis for measurement. After obtaining the measurement results, the remaining entangled photons after the random inspection are measured. During the measurement process, the two legal users independently select a basis. The specific basis selection can be determined by different protocols. The two parties of the agreement compare the basis and post-process the measurement results. The post-processing process is no different from the common BB84 protocol, and the quantum key is finally extracted.

[0142] It should be noted that for the aforementioned method embodiments, for simplicity of description, they are all expressed as a series of action combinations. However, those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in this specification are all preferred embodiments, and the actions involved are not necessarily required for this application.

[0143] Based on the description of the above method embodiments, the present application also provides corresponding device embodiments to implement the contents described in the above method embodiments.

[0144] Reference Figure 6 , which shows a schematic diagram of a quantum key distribution device based on quantum relay according to an embodiment of the present application, including:

[0145] The photon number entangled state module 601 is used to input the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain the maximum photon number entangled state;

[0146] Conversion module 602, for converting the maximum number of photons entangled state to obtain a path maximum entangled state;

[0147] The generation module 603 is used to process the maximum entangled state of the path to generate a quantum key.

[0148] Optionally, the conversion module includes:

[0149] A selection unit, configured to select a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled state with a maximum number of photons;

[0150] A conversion unit is used to input the first maximum photon number entangled state and the second maximum photon number entangled state into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

[0151] Optionally, the path coding projection measurement device includes: a first path coding module and a second path coding module;

[0152] The conversion unit includes:

[0153] A first path submodule, configured to input the first photon number maximum entangled state into the first path encoding module to obtain a first path maximum entangled state;

[0154] A second path submodule, configured to input the second photon number maximum entangled state into the second path encoding module to obtain a second path maximum entangled state;

[0155] a screening submodule, configured to screen the first path maximum entangled state and the second path maximum entangled state according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state;

[0156] A generating submodule is used to generate the path maximum entangled state according to the screened first path maximum entangled state and the screened second path maximum entangled state.

[0157] Optionally, the generating module includes:

[0158] A Bell state measurement unit, configured to perform a Bell inequality test on the maximum entangled state of the path to obtain a Bell inequality measurement result;

[0159] A generating unit is configured to generate a quantum key according to the path maximum entangled state if the Bell inequality measurement result determines that the path maximum entangled state belongs to the maximum entangled state.

[0160] Optionally, the first photon pair includes: a first photon and a second photon, and the second photon pair includes: a third photon and a fourth photon;

[0161] The photon number entangled state module is specifically used to input the first photon in the first photon pair and the third photon in the second photon pair into the beam splitter to obtain the maximum entangled state of the second photon and the fourth photon; and the maximum entangled state of the second photon and the fourth photon is used as the maximum entangled state of the photon number.

[0162] In this embodiment, the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair are input into a beam splitter to obtain a maximum entangled state of the photon number, the maximum entangled state of the photon number is converted to obtain a maximum entangled state of the path, and then the maximum entangled state of the path is processed to generate a quantum key. Since the maximum entangled state of the path is obtained by converting the maximum entangled state of the photon number, key distribution is realized based on the maximum entangled state of the path, thereby constructing a quantum key distribution over a longer distance, which avoids the use of intermediate quantum relays, making quantum key distribution more secure and practical, thereby improving the security of the QKD link.

[0163] As for the above-mentioned device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0164] An embodiment of the present invention further provides a relay node deployment device, including:

[0165] memory; processor; and computer program;

[0166] The computer program is stored in the memory and is configured to be executed by the processor to implement the quantum key distribution method based on quantum relay.

[0167] An embodiment of the present invention also provides a computer-readable storage medium on which a computer program is stored. The computer program is executed by a processor to implement the quantum key distribution method based on quantum relay.

[0168] Alternatively, the computer-readable storage medium may be a non-transitory computer-readable storage medium, for example, the non-transitory computer-readable storage medium may be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

[0169] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0170] Those skilled in the art will readily appreciate that any combination of the above-described embodiments is feasible, and therefore any combination of the above-described embodiments is an embodiment of the present invention. However, due to space limitations, this specification does not describe each of the embodiments in detail. Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as covering the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0171] The above is a detailed introduction to the quantum key distribution method, device, equipment and medium based on quantum relay provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A quantum key distribution method based on quantum relay, characterized in that: include: Inputting the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain an entangled state with a maximum number of photons; Converting the maximum photon number entangled state to obtain a path maximum entangled state; Processing the maximum entangled state of the path to generate a quantum key; The converting the photon maximum entangled state to obtain the path maximum entangled state includes: Selecting a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled states with a maximum number of photons; The first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons are input into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

2. The method according to claim 1, characterized in that The path coding projection measurement device includes: a first path coding module and a second path coding module; Inputting the first entangled state with the maximum number of photons and the second entangled state with the maximum number of photons into a path coding projection measurement device for conversion to obtain the path maximum entangled state includes: Inputting the first photon number maximum entangled state into the first path encoding module to obtain a first path maximum entangled state; Inputting the second maximum photon number entangled state into the second path encoding module to obtain the second path maximum entangled state; screening the first path maximum entangled state and the second path maximum entangled state according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state; The path maximum entangled state is generated according to the screened first path maximum entangled state and the screened second path maximum entangled state.

3. The method according to claim 1, characterized in that The processing of the maximum entangled state of the path to generate a quantum key includes: Performing a Bell inequality test on the maximum entangled state of the path to obtain a Bell inequality measurement result; If the Bell inequality measurement result determines that the path maximum entangled state belongs to the maximum entangled state, a quantum key is generated according to the path maximum entangled state.

4. The method according to claim 1, wherein The first photon pair includes: a first photon and a second photon, and the second photon pair includes: a third photon and a fourth photon; Inputting the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain the entangled state with the maximum number of photons includes: Inputting the first photon of the first photon pair and the third photon of the second photon pair into the beam splitter to obtain a maximum entangled state of the second photon and the fourth photon; The maximum entangled state of the second photon and the fourth photon is used as the maximum photon number entangled state.

5. A quantum key distribution device based on quantum relay, characterized in that: include: A photon number entangled state module is used to input the maximum entangled state of the first photon pair and the maximum entangled state of the second photon pair into the beam splitter to obtain a maximum photon number entangled state; A conversion module for converting the maximum photon number entangled state to obtain a path maximum entangled state; A generation module for processing the maximum entangled state of the path to generate a quantum key; The conversion module includes: A selection unit, configured to select a first entangled state with a maximum number of photons and a second entangled state with a maximum number of photons from the entangled state with a maximum number of photons; A conversion unit is used to input the first maximum photon number entangled state and the second maximum photon number entangled state into a path coding projection measurement device for conversion to obtain the path maximum entangled state.

6. The device according to claim 5, characterized in that The path coding projection measurement device includes: a first path coding module and a second path coding module; The conversion unit includes: A first path submodule, configured to input the first photon number maximum entangled state into the first path encoding module to obtain a first path maximum entangled state; A second path submodule, configured to input the second photon number maximum entangled state into the second path encoding module to obtain a second path maximum entangled state; a screening submodule, configured to screen the first path maximum entangled state and the second path maximum entangled state according to a detector screening rule to obtain a screened first path maximum entangled state and a screened second path maximum entangled state; A generating submodule is used to generate the path maximum entangled state according to the screened first path maximum entangled state and the screened second path maximum entangled state.

7. A relay node deployment device, characterized in that: include: Memory; Processor; and computer programs; The computer program is stored in the memory and is configured to be executed by the processor to implement the quantum key distribution method based on quantum relay as described in any one of claims 1 to 4.

8. A computer-readable storage medium, characterized in that A computer program is stored thereon, and the computer program is executed by a processor to implement a quantum key distribution method based on quantum relay as described in any one of claims 1 to 4.

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