Efficient device-independent quantum secret sharing method based on single photon source

Abstract

The invention discloses an efficient device-independent quantum secret sharing method based on a single photon source. The QSS allows a plurality of users to each obtain a portion of the shared key, and each user finally reads the shared key through cooperation. Three users use a single photon source to prepare two single photons, a variable beam splitter is used to send one photon to a fourth party for GHZ state measurement, and the other photon is stored. And when the fourth party GHZ state measurement is successful, the photons stored in the three parties establish long-distance entanglement. And each user extracts the stored photons and randomly selects a measurement basis to measure the photons for DI security detection and sub-key generation. And finally, the user B and the user C cooperate to read the shared key transmitted by the user A. According to the method, all attacks from imperfect equipment can be resisted, and the highest-level security protection is provided for the QSS. An entanglement channel is constructed by using a high-efficiency single photon source, so that the communication distance of DI-QSS can be prolonged by 308 times, and the actual communication efficiency is improved by 3125,000 times.

Description

Technical Field

[0001] The present invention belongs to the technical field of quantum communication, relates to quantum secret sharing technology, and specifically relates to an efficient device-independent quantum secret sharing method based on a single-photon source. Background Art

[0002] Quantum secret sharing (QSS) is a technology that uses the basic principles of quantum mechanics to achieve secure secret sharing. It has the ability to detect eavesdropping, which is a huge advantage compared with classical secret sharing. QSS allows a key distributor to split a complete key into multiple sub-keys and distribute them to multiple users. Only legitimate users can reconstruct the original complete key through cooperation. Although QSS theoretically has unconditional security, in actual QSS systems, factors such as device defects open eavesdropping loopholes for eavesdroppers and cannot guarantee the security of the communication process.

[0003] The basic idea of device-independent (DI) is to regard all devices in the system as black boxes. The communicating parties do not care about the internal operation process of the black boxes, but only care about the input and output results of the black boxes. The security guarantee of communication comes from the non-local correlation of photons among all communicating parties, that is, the violation of Bell's inequality. Therefore, quantum communication protocols based on DI can resist all attacks on imperfect device ends and provide the highest level of security protection for quantum communication.

[0004] In 2019, Roy proposed the first DI-QSS method. However, they did not give important performance parameters such as the key generation rate and detection efficiency threshold in the actual communication process of DI-QSS, which has no guiding significance for DI-QSS experiments. In 2024, our research group proposed a DI-QSS method based on a cascaded SPDC source. This method aims to generate three-photon GHZ states using a cascaded SPDC source and perform long-distance entanglement distribution. Since the success probability of preparing three-photon GHZ states by a cascaded SPDC source is relatively low (about 10 -8 ), and the photon transmission loss in the entanglement distribution process greatly reduces the non-local correlation between photons, resulting in a relatively low actual communication efficiency of this method and a very short photon secure transmission distance, which affects its practicality. Under the current experimental conditions, the single-photon generation rate of a single-photon source is close to 100%, and its performance is close to that of an ideal source. Therefore, the present invention proposes an efficient DI-QSS protocol based on a single-photon source. Using a single-photon source to generate single photons and combining with indicating GHZ state measurement to construct a long-distance entanglement channel, and the influence of photon transmission loss on the non-local correlation of channel photons can be eliminated. Compared with the DI-QSS protocol based on a cascaded SPDC source, this method can increase the communication distance by about 308 times and the actual communication efficiency by about 3.125 million times. This method is based on linear optical elements and can be realized under the current experimental conditions, and has important application prospects in the field of quantum communication. Summary of the Invention

[0005] The object of the present invention is to overcome the deficiencies in the prior art and solve the problems of short communication distance and low actual communication efficiency of the DI-QSS method in the actual environment. The present invention also gives important performance parameters such as the maximum transmission distance of photons and the actual communication efficiency.

[0006] To solve the above technical problems, based on DI-QSS, the present invention combines a single-photon source and an indicative GHZ state measurement to provide an efficient device-independent quantum secret sharing method based on a single-photon source. The method comprises the following steps:

[0007] Step S1: At each user end of user A, user B, and user C, there are two single-photon sources, which respectively prepare single photons in the horizontal polarization state |H> and the vertical polarization state |V>, and make the two photons reach a variable beam splitter simultaneously. The photons at the reflection end of the variable beam splitter are stored using a quantum memory, and the photons at the transmission end are sent through a quantum channel to a fourth party for GHZ state measurement; only when the fourth party announces the success of the GHZ state measurement and photons are stored in the quantum memories of all three users, the photons stored by the three parties successfully establish entanglement, which is called a successful entanglement event; otherwise, all the photons in the quantum memories of the three parties are discarded, and a new round of single-photon transmission is carried out until successful entanglement is established.

[0008] Step S2: Under the condition of a successful entanglement event, the three users read photons from their own quantum memories and independently and randomly select measurement bases for measurement; among them, user A has two measurement base choices, namely A1 and A2, user B has three measurement base choices, namely B1, B2, and B3, and user C has two measurement base choices, namely C1 and C2; any user using any one of the measurement bases has two measurement results of "+1" and "-1"; if all the detectors of any party do not respond, then the user marks the measurement result as "⊥"; after all the photons are measured, user A, user B, and user C announce the measurement bases of each photon.

[0009] Step S3: When the measurement base combination of user A, user B, and user C is {A1B1C1}, the measurement results of the three parties will be used to transmit the key; when the measurement base combination of user A, user B, and user C is one of 8 parameter estimation combinations, the three parties all announce the measurement results for estimating the value S of the Svetlichny polynomial ABC , and the value S of the CHSH polynomial at user A and user B AB ; when S AB > 2, which is equivalent to S ABC > 4, it indicates that the photon transmission process of the three parties is secure and the communication continues; when S AB ≤ 2, which is equivalent to S ABC ≤ 4, it indicates that the photon transmission process of the three parties is insecure and the communication is terminated.

[0010] Step S4: When the measurement basis combinations of User A, User B, and User C are {A1B1C1}, User A randomly announces the measurement results of some photons, and User B and User C disclose the measurement results of the corresponding photons. The data comparison among the three parties is used to estimate the quantum bit error rate δ; for the remaining unannounced measurement results, User B and User C retain the measurement results to generate sub-keys;

[0011] Step S5: Repeat Step S1 - Step S4 until User B and User C obtain a sufficient number of sub-keys;

[0012] Step S6: User A, User B, and User C perform error correction and privacy amplification on the obtained keys over an authenticated classical channel, and finally form secure sub-keys;

[0013] Step S7: User C announces its secure sub-key, and User B can infer the secure key shared by User A by combining its own sub-key.

[0014] The present invention provides an efficient device-independent quantum secret sharing method based on a single-photon source. The beneficial effects include:

[0015] 1. This method can resist all attacks against imperfect device terminals and provide the highest level of security protection for QSS.

[0016] 2. Using an efficient single-photon source under current experimental conditions to generate single photons and combining with indicating GHZ state measurements to construct a long-distance entanglement channel can eliminate the influence of photon transmission loss on the non-local correlation of channel photons. Compared with the DI-QSS protocol based on a cascaded SPDC source, this method can increase the communication distance by about 308 times and the actual communication efficiency by about 3.125 million times.

[0017] 3. This method is based on linear optical conditions and can be implemented under current experimental conditions. Description of the Drawings

[0018] Figure 1 is a flowchart of an efficient device-independent quantum secret sharing method based on a single-photon source provided by an embodiment of the present invention.

[0019] Figure 2 is a schematic diagram of the principle of an efficient device-independent quantum secret sharing method based on a single-photon source provided by an embodiment of the present invention.

[0020] Figure 3 is a structural diagram of each module device provided by an embodiment of the present invention. Figure 3 (a) is a schematic diagram of the structure of the GHZ state measurement module, Figure 3 (b) is a schematic diagram of the structure of the quantum memory module.

[0021] Figure 4 This is a comparison chart of the actual communication efficiency between the present invention and the existing DI-QSS. Detailed implementation manners

[0022] The present invention will be further illustrated below in conjunction with the accompanying drawings and specific embodiments.

[0023] As Figure 1 shown, the present invention provides an efficient device-independent quantum secret sharing method based on a single photon source, including the following steps:

[0024] Step S1: At each user terminal of user A, user B, and user C, there are two single photon sources, which respectively prepare single photons in the horizontal polarization state |H> and the vertical polarization state |V>. The two photons reach a variable beam splitter (VBS) simultaneously. The photons at the reflection end of the VBS are stored using a quantum memory, and the photons at the transmission end are sent through a quantum channel to a fourth party for GHZ state measurement. Only when the fourth party announces that the GHZ state measurement is successful and photons are stored in the quantum memories of all three users, the photons stored by the three parties successfully establish entanglement, which is called a successful entanglement event. Otherwise, all the photons in the quantum memories of the three parties are discarded, and a new round of single photon transmission is carried out until entanglement is successfully established.

[0025] As Figure 2 , it shows a schematic diagram of the principle of an efficient device-independent quantum secret sharing based on a single photon source. Specifically: on the side of user A, there are two single photon sources S1 and S2 and a quantum memory QM1; on the side of user B, there are two single photon sources S3 and S4 and a quantum memory QM2; on the side of user C, there are two single photon sources S5 and S6 and a quantum memory QM3. The single photon sources S1, S3, and S5 prepare single photons in the horizontal polarization state |H>, and S2, S4, and S6 prepare single photons in the vertical polarization state |H>. Then, each of the three users passes their own photons through a variable beam splitter (VBS) with a transmittance of T. The photons at the transmission end (a p1 、b p1 and c p1 ) of the VBS are sent through the quantum channel to the fourth party GHZ state measurement module located at the center of the three parties. The photons at the reflection end (a p2 、b p2 and c p2 ) of the VBS reach the quantum memory QM1, QM2, and QM3 modules respectively. Specifically, the photon states at the positions of user A, user B, and user C evolve into

[0026]

[0027] In order to successfully establish entanglement, only the paths a p1 、bp1 and c p1 all photons of reach the GHZ state measurement module and a p2 , b p2 and c p2 all reach the quantum memory module, where a p1 , b p1 and c p1 are lossy channels with a transmission efficiency of η t . Then, the quantum state collapses to

[0028]

[0029] where and

[0030] The structure of the GHZ state measurement module is as shown in (a) of Figure 3 . Photons in path a p1 , b p1 and c p1 enter the GHZ state measurement module from ports A in , B in and C in respectively. This measurement device can only correctly identify two GHZ states, namely where the corresponding response situation is that detectors D 1H , D 2H and D 3H respond, or D 1H , D 2V and D 3V respond, or D 1V , D 2H and D 3V respond, or D 1V , D 2V and D 3H respond; the corresponding response situation is that D 1V , D 2V and D 3V respond, or D 1H , D 2H and D 3V respond, or D 1V , D 2H and D 3H respond, or D 1H , D 2V and D 3H respond. When the result announced by the GHZ state measurement module is , add a phase flip module in front of the measurement device of user A for Convert to The phase flip module consists of two QWPs and one HWP. Specifically,

[0031]

[0032] Therefore, the probability P that the photons in the three quantum memories QM1, QM2, and QM3 successfully establish GHZ state entanglement d is

[0033]

[0034] The structure of the quantum memory module is as shown in Figure 3 (b). The photons in paths a p2 , b p2 and c p2 enter from the in ports of their respective quantum memories and are output from the out ports. The electro-optic modulator (EOM) in the open state can change the polarization state of the photons, that is it will not affect the polarization state of the photons in the closed state In addition, the combination of a quarter-wave plate (QWP) and a mirror causes the photons to pass through the QWP twice, achieving a 90-degree deflection of the polarization state, that is When a photon enters the quantum memory, the state of the EOM changes from closed to open. To read the photon, the state of the EOM is changed from open to closed. The photons output from the out port have a bit flip compared to their state before input. Therefore, the output photons need to pass through a half-wave plate (HWP) to be restored to the initial state, that is The detailed principle of the memory is as follows:

[0035]

[0036]

[0037] Step S2: Under the condition of a successful entanglement event, the three users read the photons from their own quantum memories and independently and randomly select measurement bases for measurement. Among them, user A has two measurement basis choices, namely A1 = σ x , A2 = σ y , user B has three measurement basis choices, namely B1 = σ x , user C has two measurement basis choices, namely C1 = σ x , C2 = -σ y . Among them, σ x and σ y are Pauli matrices, and their specific forms are:

[0038]

[0039] The measurement results corresponding to the measurement bases of User A, User B, and User C are marked as {a1, a2}, {b1, b2, b3}, and {c1, c2} respectively. The measurement results of the three parties of users for all measurement bases are +1 or -1, that is, a1, a2, b1, b2, b3, c1, c2 ∈ {-1, +1}. If all detectors of any party do not respond, the measurement result of this user is marked as "⊥". After all photons are measured, User A, User B, and User C announce the measurement bases of each photon.

[0040] Step S3: User A, User B, and User C randomly select measurement bases, and there are the following three cases:

[0041] Case 1: When the measurement base combination of User A, User B, and User C is {A1B1C1}, the measurement results of the three parties will be used to transmit the key.

[0042] Case 2: When the measurement base combination of User A, User B, and User C is one of the 8 parameter estimation base combinations {A1B2C1}, {A2B2C1}, {A1B2C2}, {A2B2C2}, {A1B3C1}, {A2B3C1}, {A1B3C2}, or {A2B3C2}, all three parties announce their measurement results to estimate the value S of the Svetlichny polynomial ABC , and the value S of the CHSH polynomial at User A and User B AB . When S AB > 2 (equivalent to S ABC > 4), it indicates that the photon transmission process of the three parties is secure and the communication continues; when S AB ≤ 2 (equivalent to S ABC ≤ 4), it indicates that the photon transmission process of the three parties is insecure and the communication is terminated.

[0043] Case 3: When the measurement base combination of User A, User B, and User C is {A1B1C2}, {A2B1C1}, {A2B1C2}, the three users need to discard their measurement results.

[0044] Specifically: If the base selection combination of the three parties is one of the 8 parameter estimation base combinations, all three parties announce their measurement results, and the value S of the Svetlichny polynomial is estimated according to all measurement results ABC :

[0045] S ABC = <a1b2c2> + <a1b3c1> + <a2b2c1> - <a2b3c2> + <a2b3c2> + <a2b3c1> + <a2b2c2> + <a1b3c2> - <a1b2c1>

[0046] Among them, <a i b j c k > = P(a i b j c k = 1) - P(a i b j c k = -1), i ∈ {1, 2}, j ∈ {2, 3}, k ∈ {1, 2} represents the statistical expected value of the measurement results when user A selects A i measurement, user B selects B j measurement, and user C selects C k measurement. In fact, the Svetlichny polynomial can adopt the CHSH polynomial S AB to represent:

[0047] S ABC = S AB c2 + S' AB c1

[0048] Among them, c1 and c2 respectively represent the measurement results when user C selects the measurement bases C1 and C2, and S AB represents the value of the CHSH polynomial between user A and user B, and S' AB is obtained by performing an equivalent transformation on the CHSH polynomial S AB . The specific expressions of S AB and S' AB are:

[0049] S AB = <a1b2> + <a2b2> + <a1b3> - <a2b3>

[0050] S' AB ＝ <a2b3> + <a2b2> + <a1b3> - <a1b2>

[0051] Among them, <a i b j > = P(a i b j = 1) - P(a i b j = -1), i ∈ {1, 2}, j ∈ {2, 3} represents the statistical expected value of the measurement results when user A selects A i measurement and user B selects B j measurement.

[0052] Since in the parameter estimation basis combination, user C announces all its measurement results, it is only necessary to ensure that the CHSH inequality (S AB ≤ 2) is violated at user A and user B, then it can be ensured that the measurement results of the three parties violate the Svetlichny inequality S ABC ≤ 4, thus ensuring the security of the photon transmission process.

[0053] Step S4: When the measurement basis combinations of user A, user B, and user C are {A1B1C1}, user A randomly announces the measurement results of some photons, user B and user C publicly announce the measurement results of the corresponding photons, and the three parties compare the data to estimate the quantum bit error rate δ. For the remaining unannounced measurement results, user B and user C retain the measurement results to generate sub-keys.

[0054] When user A, user B, and user C respectively select the A1, B1, and C1 measurement bases, the GHZ state is rewritten as:

[0055]

[0056] Among them, |+> corresponds to the measurement result "+1", and |-> corresponds to the measurement result "-1".

[0057] After the three parties obtain the initial measurement values, user A randomly announces the measurement results a1 of some photons, and user B and user C announce the measurement results of the corresponding photons. If the measurement result combination is different from {+1, +1, +1}, {+1, -1, -1}, {-1, +1, -1}, or {-1, -1, +1}, it is considered an error. The three parties estimate the quantum bit error rate δ based on the announced results. The remaining unannounced photon measurement results are used by the three parties to generate the original key. We mark the measurement result "+1" as the key bit "0" and the measurement result "-1" as the key bit "1". The above coding rule is summarized as: Among them, k A 、k B and k C respectively represent the key bits of user A, user B, and user C, It is an exclusive OR operation. Based on his own and combining with the announced results of User C, User B can infer the key transmitted by User A.

[0058] For example, if User B's photon measurement result is "+1" (key bit is 0) and User C's corresponding announced photon measurement result is -1 (key bit is 1), at this time, User B can infer that User A's measurement result is -1, that is, the key transmitted by User A is 1.

[0059] Step S5: Repeat Step S1 - Step S4 until User B and User C obtain a sufficient number of keys.

[0060] Step S6: User A, User B, and User C perform error correction and privacy amplification on the obtained keys over an authenticated classical channel to finally form a secure key.

[0061] Step S7: User C announces its secure sub - key, and User B can infer the secure key shared by User A by combining its own sub - key.

[0062] This method takes into account the impact of photon transmission loss on key transfer in the actual environment. In the actual environment, photon loss occurs, which will cause S ABC (S AB ) to decrease. The maximum value of the CHSH polynomial S AB at User A and User B is S m :

[0063]

[0064] Among them, the signal sent through the quantum channel will have local loss, that is, the probability that the photon signal is successfully received by the detector is η l . When η l < 1, Therefore, an eavesdropper can intercept photons and cause partial key leakage.

[0065] We can estimate the maximum secrecy rate H(A1|E) for the eavesdropper:

[0066]

[0067] Among them, h(x) is the binary Shannon entropy:

[0068] h(x) = -x log2 x - (1 - x)log2(1 - x)

[0069] When , then the maximum secrecy rate H(A1|E) for the eavesdropper is 1, and the eavesdropper cannot obtain any keys, that is, the key leakage rate of the method is 0. When When H(A1|E) < 1, that is, the eavesdropper can steal some photons, but the communicating parties can estimate the upper bound of the key leakage rate. For the above two cases, all three users consider the key transmission process to be secure. When S m ≤ 2, the eavesdropper can steal all the photons without being detected. At this time, the photon transmission process is not secure, and the communication is abandoned and the channel is re-detected.

[0070] The error rate of photon transmission information Therefore, the information error rate H(A1|B1,C1) of user B with respect to user A:

[0071]

[0072] So, the key generation rate r is obtained as

[0073]

[0074] 50% of the entangled photon pairs are used to estimate the Svetlichny polynomial (CHSH polynomial), so that P c = 50% × 25% = 12.5% of the photons are used to transmit the key. The repetition rate R of each single-photon source rep is 10 MHz. Therefore, the actual communication efficiency E of DI-QSS c is

[0075]

[0076] Figure 4 Shows the comparison diagram of the actual communication efficiency between the present invention and the existing DI-QSS. The present invention uses a single-photon source and GHZ state measurement to implement a new DI-QSS, which increases the communication distance by about 308 times and the actual communication efficiency by about 3.125 million times.

[0077] The above is only a demonstration case of the present invention. The protection scope of the present invention is not limited to the above embodiments. Any equivalent modification or change made by those of ordinary skill in the art according to the disclosure of the present invention shall be included in the protection scope recorded in the claims. < / a1b3> < / a2b2> < / a2b3> < / a2b3> < / a1b3> < / a2b2> < / a1b2> < / a1b3c2> < / a2b2c2> < / a2b3c1> < / a2b3c2> < / a2b3c2> < / a2b2c1> < / a1b3c1> < / a1b2c2>

Claims

1. An efficient device-independent quantum secret sharing method based on a single photon source, characterized in that: The method comprises the following steps: Step S1: Each of the user terminals of User A, User B, and User C has two single-photon sources, which respectively prepare single photons in the horizontal polarization state |H> and the vertical polarization state |V>. Two photons reach a variable beam splitter simultaneously. The photons at the reflection end of the variable beam splitter are stored using a quantum memory, and the photons at the transmission end are sent through a quantum channel to a fourth party for GHZ state measurement. Only when the fourth party announces that the GHZ state measurement is successful and there are photons stored in the quantum memories of all three users, the photons stored by the three parties successfully establish entanglement, which is called a successful entanglement event. Otherwise, all the photons in the quantum memories of the three parties are discarded, and a new round of single-photon transmission is carried out until successful entanglement is established. Step S2: Under the condition of a successful entanglement event, the three users read photons from their own quantum memories and independently and randomly select measurement bases for measurement. Among them, User A has two measurement basis options, namely A1 and A2; User B has three measurement basis options, namely B1, B2, and B3; User C has two measurement basis options, namely C1 and C2. Any user using any one of the measurement bases has two measurement results, namely "+1” and "-1”. If all the detectors of any party do not respond, then the measurement result of this user is marked as "⊥”. After all the photons are measured, User A, User B, and User C announce the measurement basis of each photon. Step S3: When the measurement basis combinations of User A, User B, and User C are {A1B1C1}, the measurement results of the three parties will be used to transmit the key; when the measurement basis combinations of User A, User B, and User C are the 8 parameter estimation combinations, all three parties announce the measurement results for estimating the value S of the Svetlichny polynomial ABC , and the value S of the CHSH polynomial at User A and User B AB ; when S AB > 2, which is equivalent to S ABC > 4, it indicates that the photon transmission process among the three parties is secure and the communication continues; when S AB ≤ 2, which is equivalent to S ABC ≤ 4, it indicates that the photon transmission process among the three parties is insecure and the communication is terminated; Step S4: When the measurement basis combination of User A, User B, and User C is {A1B1C1}, User A randomly announces the measurement results of some photons, and User B and User C disclose the measurement results of the corresponding photons. The three parties compare the data to estimate the quantum bit error rate δ. For the remaining unannounced measurement results, User B and User C retain the measurement results to generate sub-keys. Step S5: Repeat Step S1 - Step S4 until User B and User C obtain a sufficient number of sub-keys. Step S6: User A, User B, and User C perform error correction and privacy amplification on the obtained keys over an authenticated classical channel, and finally form a secure sub-key. Step S7: User C announces its secure sub-key, and User B can infer the secure key shared by User A in combination with its own sub-key.

2. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In the said Step S1, on the side of User A, there are two single-photon sources S1 and S2 and a quantum memory QM1; on the side of User B, there are two single-photon sources S3 and S4 and a quantum memory QM2; on the side of User C, there are two single-photon sources S5 and S6 and a quantum memory QM3. The single-photon sources S1, S3, and S5 prepare single photons in the horizontal polarization state |H>, and the single-photon sources S2, S4, and S6 prepare single photons in the vertical polarization state |H>. Then, each of the three users transmits their own photons through a variable beam splitter (VBS) with a transmittance of T. The photons at the transmission ends (a p1 , b p1 , and c p1 ) of the variable beam splitter are sent to the fourth-party GHZ state measurement module located at the center of the three parties through a quantum channel. The photons at the reflection ends (a p2 , b p2 , and c p2 ) of the variable beam splitter reach the quantum memory modules QM1, QM2, and QM3 respectively. Denote P d as the probability that the photons in the three memories successfully establish GHZ state entanglement.

3. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In the step S1, the GHZ state measurement module can only correctly identify two GHZ states, namely wherein, the corresponding response situation is that detectors D 1H , D 2H and D 3H respond, or D 1H , D 2V and D 3V respond, or D 1V , D 2H and D 3V respond, or D 1V , D 2V and D 3H respond; the corresponding response situation is that D 1V , D 2V and D 3V respond, or D 1H , D 2H and D 3V respond, or D 1V , D 2H and D 3H respond, or D 1H , D 2V and D 3H respond.

4. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In the step S1, photons in paths a p2 , b p2 and c p2 of the quantum memory module enter from the in-port of their respective quantum memories and are output from the out-port; An electro-optic modulator in the open state can change the polarization state of photons, that is it will not affect the polarization state of photons in the closed state The combination of a quarter-wave plate and a mirror will cause the photons to pass through the quarter-wave plate twice, achieving a 90-degree deflection of the polarization state, that is When a photon enters the quantum memory, the state of the electro-optic modulator changes from closed to open; if the photon needs to be read, the state of the electro-optic modulator changes from open to closed; the photons output from the out port have a bit flip compared to their state before input, so the output photons need to pass through a half-wave plate to be restored to the initial state, that is 5. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In the said step S2, user A has two choices of measurement bases, namely A1 = σ x , A2 = σ y ; user B has three choices of measurement bases, namely B1 = σ x , ; user C has two choices of measurement bases, namely C1 = σ x , C2 = -σ y ; where, σ x and σ y are Pauli matrices, and their specific forms are as follows: The measurement results corresponding to the measurement bases of user A, user B, and user C are respectively marked as {a1, a2}, {b1, b2, b3}, {c1, c2}; the measurement results of the three-party users under all measurement bases are +1 or -1, that is, a1, a2, b1, b2, b3, c1, c2 ∈ {-1, +1}; if all detectors of any party do not respond, the measurement result of this user is marked as "⊥".

6. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In step S3, in addition to the code-forming basis combination {A1B1C1}, and the 8 parameter estimation basis combinations {A1B2C1}, {A2B2C1}, {A1B2C2}, {A2B2C2}, {A1B3C1}, {A2B3C1}, {A1B3C2}, and {A2B3C2}, there are also 3 combinations of measurement bases for the three parties, namely {A1B1C2}, {A2B1C1}, {A2B1C2}; if the combination of measurement bases announced by the three users belongs to one of these three, the three parties need to discard their own measurement results.

7. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 6, characterized in that: In the step S3, if the three-party basis combination is one of the eight parameter estimation basis combinations, all three parties announce their measurement results; all the measurement results are used to estimate the value S of the Svetlichny polynomial. ABC : S ABC ＝ <a1b2c2> + <a1b3c1> + <a2b2c1> - <a2b3c2> + <a2b3c2> + <a2b3c1> + <a2b2c2> + <a1b3c2> - <a1b2c1>< / a1b2c1> < / a1b3c2> < / a2b2c2> < / a2b3c1> < / a2b3c2> < / a2b3c2> < / a2b2c1> < / a1b3c1> < / a1b2c2> Among them, <a i b j c k > = P(a i b j c k = 1) - P(a i b j c k = -1), i, k ∈ {1, 2}, j ∈ {2, 3} represents the statistical expected value of the measurement results when user A selects A i measurement, user B selects B j measurement, and user C selects C k measurement; The Svetlichny polynomial uses the CHSH polynomial S AB denotes: S ABC = S AB c2 + S' AB c1 Among them, C1 and c2 respectively represent the measurement results of user C choosing measurement bases C1 and C2, S AB represents the value of the CHSH polynomial for users A and B, and S' AB is obtained by performing an equivalent transformation on the CHSH polynomial S AB ; the specific expressions of S AB and S' AB are as follows: S AB ＝ <a1b2> + <a2b2> + <a1b3> - <a2b3>< / a2b3> < / a1b3> < / a2b2> < / a1b2> S′ AB ＝ <a2b3> + <a2b2> + <a1b3> - <a1b2>< / a1b2> < / a1b3> < / a2b2> < / a2b3> Among them, <a i b j > = P(a i b j = 1) - P(a i b j = -1), i ∈ {1, 2}, j ∈ {2, 3} represents the statistical expected value of the measurement results when user A selects A i measurement and user B selects B j measurement.

8. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In step S4, when user A, user B, and user C respectively select the A1, B1, and C1 measurement bases, the GHZ state is rewritten as: Among them, |+> corresponds to the measurement result of "+1", and |-> corresponds to the measurement result of "-1"; After the three parties obtain the initial measurement values, user A randomly announces the measurement results a1 of some photons, and user B and user C announce the measurement results of the corresponding photons; if the measurement result combination is different from {+1, +1, +1}, {+1, -1, -1}, {-1, +1, -1}, or {-1, -1, +1}, it is considered that an error has occurred; the three parties estimate the quantum bit error rate δ according to the announced results; the measurement results of the remaining unannounced photons are used for the three parties to generate the original key; Mark the measurement result of "+1" as the key bit "0", and the measurement result of "-1" as the key bit "1"; the above coding rule is summarized as: where k A , k B and k C represent the key bits of user A, user B, and user C respectively, is the exclusive OR operation; user B infers the key transmitted by user A based on his own and combining the announced results of user C.

9. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: Photon loss in the actual environment will cause S ABC (S AB ) to decrease; the maximum value of the CHSH polynomial S AB at user A and user B is S m : Among them, the signal sent through the quantum channel will experience local loss, that is, the probability that the photon signal is successfully received by the detector is η l ; when η l < 1, Therefore, eavesdroppers can intercept photons, resulting in partial key leakage; Estimate the maximum secrecy rate H(A1|E) against the eavesdropper: where h(x) is the binary Shannon entropy: h(x) = -x log2 x - (1 - x)log2(1 - x) When happens, the maximum secrecy rate H(A1|E) for the eavesdropper is 1, and the eavesdropper cannot obtain any key, that is, the key leakage rate of the method is 0; when happens, then H(A1|E) < 1, that is, the eavesdropper can steal some photons, and the communicating parties can estimate the upper bound of the key leakage rate; for the above two cases, all three users consider the key transmission process to be secure; when S m ≤ 2, the eavesdropper can steal all the photons without being detected. At this time, the photon transmission process is insecure, abandon the communication, and re-detect the channel.

10. An efficient device-independent quantum secret sharing method based on a single-photon source according to claim 1, characterized in that: In the step S4, the error rate of photon transmission information Therefore, the error rate of user A's information for user B, H(A1|B1,C1): Therefore, the key generation rate r is obtained as 50% of the entangled photon pairs are used to estimate the Svetlichny polynomial, i.e., the CHSH polynomial, so that there is P c = 50% × 25% = 12.5% of the photons are used to transmit the key; therefore, the actual communication efficiency E of DI-QSS c is Among them, η t represents the probability that a photon successfully reaches the GHZ state measurement module after passing through paths a p1 , b p1 and c p1 . The repetition rate R of each single photon source rep is 10 MHz.

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