A quantum conference key agreement method with parameter-independent channels

Abstract

The present invention relates to a quantum conference key negotiation method with a parameter-independent channel, comprising: N participants, wherein Alice is the conference initiator, A j (j=1,2…N‑1) are the conference participants. Alice prepares 2L×(N‑1) non-maximally entangled GHZ state particle pairs and divides these particles into (N‑1) sequences, each sequence corresponds to a participant. Then the initiator divides the particles in each sequence into two groups #imgabs0# and #imgabs1# and sends #imgabs2# to the participants corresponding to each sequence through the quantum channel. After all participants perform Bell measurements on the particles they hold, they can obtain the common M between Alice and each participant. j Finally, Alice operates #imgabs3# and sends it to the corresponding participants through the quantum channel for Bell measurement. Then all participants can obtain a j The mutual key K with Alice j and a shared key K that is equally shared by all participants.

Description

Technical Field

[0001] The invention relates to the technical field of quantum secure communication, and in particular to a quantum conference key negotiation method with a parameter-independent channel. Background Art

[0002] With the realization of quantum computers, the public key system we currently use is no longer absolutely secure, so there is an urgent need to find a new cryptographic system whose security is not based on mathematical difficulties. Fortunately, due to the uniqueness of quantum mechanics, quantum cryptography can achieve unconditional security, and quantum cryptography has also attracted more and more attention due to its unconditional security. Quantum cryptography technology includes many branches, such as quantum key distribution, quantum secure direct communication, and quantum secret sharing.

[0003] Quantum cryptography is an interdisciplinary field that combines the principles of classical cryptography and quantum mechanics. The beginning of this field gained momentum when Bennett and Brassard introduced the first unconditionally secure quantum key distribution (QKD) BB84 protocol. In recent years, as the application scope of quantum cryptography continues to expand, quantum key agreement (QKA) has become the focus of research and an important part of quantum cryptography. At the same time, due to the large scale of communication, quantum conference key agreement (QCKA) also known as multi-party quantum key agreement protocol has also received widespread attention.

[0004] The goal of the Conference Key Agreement (CKA) protocol is to establish a shared key between multiple parties without using trusted communication methods. CKA has been explored in the quantum field with the goal of developing new cryptography and communication schemes beyond two-party key distribution. In the known literature, various quantum states have been proposed to implement CKA, including discrete variable and continuous variable states.

[0005] In addition, in our known methods, most protocols assume that the channel is in an ideal state, but in reality, there is no ideal channel. In non-ideal channels, in order to solve the problem of communication, there are two or more different noises. At the same time, Wu et al. proposed an idea to construct a special particle state that can resist two noises. The protocol requires the construction of a generalized GHZ state, a generalized unitary transformation, and a deception state of 9 particles. However, only one idea is proposed in the article, and the detailed design of the protocol is not carried out. In addition, since this method uses the entanglement of 9 particles, the quantum resource cost is high and the quantum bit efficiency is low. Recently, Zhou et al. proposed a maximum entangled GHZ state based on entanglement exchange. The two-party secret key negotiation scheme, but the maximum entangled GHZ state particles have many restrictions. Therefore, how to design a fair, secure, and efficient key negotiation protocol is still a problem that needs to be focused on. Summary of the invention

[0006] To this end, the technical problem to be solved by the present invention is to overcome the problems in the prior art of cumbersome particle state preparation steps, high quantum resource costs, inability of each participant to fairly participate in the negotiation of quantum keys, and many types of noise. To solve the above technical problems, the present invention provides a quantum conference key negotiation method with a parameter-independent channel, which uses non-maximum entangled GHZ states and performs key negotiation through entanglement exchange, and can combat collective noise when communicating through quantum channels, so that all participants can obtain a bilateral key between each conference participant and the conference initiator and a shared key K shared equally by all participants.

[0007] In order to achieve the above-mentioned purpose, the main technical scheme adopted by the present invention includes: a conference initiator and (N-1) conference participants A negotiate with the quantum conference key j (j=1,2,3…N-1); wherein all participants have passed the identity authentication of the network center server; the method comprises the steps of: the conference initiator prepares non-maximally entangled GHZ state particle pairs, obtains a particle source according to the non-maximally entangled GHZ state particle pairs, and divides the particle source into (N-1) sequences S j , and each of the sequences S j Corresponding to one of the conference participants A j Each of the sequences includes a first set of sequences And the second set of sequences The conference initiator sends the first set of sequences Staying in the local area, randomly inserting a preset number of decoy photons into the second set of sequences In the new second set of sequences and record the position and state of the inserted decoy photons; the conference initiator

[0008] The new second set of sequences Sent to the corresponding participant A j ; In each of the conference participants A j Acknowledge receipt of the new second set of sequences After that, the conference initiator announces the position of the decoy photon and the corresponding measurement basis; the conference participant A j The new second set of sequences received based on the position of the decoy photons announced by the conference initiator and the corresponding measurement basis A first measurement result is obtained by measuring, and the first measurement result is notified to the conference initiator; the conference initiator obtains a first error rate according to the first measurement result and the initial state of the decoy photon, and judges the first error rate to obtain a first judgment result; the conference participant A j Remove the new second set of sequences The decoy photons in the The conference participant A j For the second set of sequences Perform Bell measurement to obtain a second measurement result, and encode the second measurement result to obtain a sequence M j At the same time, the conference initiator Perform measurement to obtain a third measurement result, and encode the third measurement result to obtain the sequence M j , and the first set of sequences After measuring the collapse, we get the third set of sequences The conference initiator retains the sequence M obtained by it j The result of successful measurement is obtained in the sequence and publish the sequence The minimum number of bits L' in the conference initiator only retains the The number of bits in the sequence is the value before L', and the sequence M' is obtained. j ; At the same time, each of the conference participants A j According to the minimum value L' published by the conference initiator, the corresponding sequence M' is obtained in the same way j The conference initiator randomly generates a sequence M' j Sequences of the same length K A , and according to the sequence K A and the sequence M' j , get the conference initiator and the conference participant A j The conference initiator uses the shared key K to respectively Perform Pauli operation to obtain the fourth set of sequences The conference initiator is in the fourth group sequence A preset number of decoy photons are randomly added to obtain a new fourth sequence The new fourth set of sequences Sent to the corresponding conference participant A j And conduct eavesdropping detection to obtain detection results; each of the conference participants A j The fourth set of sequences received by oneself Measure and encode to get the sequence K j ; wherein the sequence K j For the conference initiator and each of the conference participants A j A separate key between each of the conference participants A j According to the sequence M' jand the sequence K j The shared key K is obtained.

[0009] In one embodiment of the present invention, the conference initiator prepares 2L×(N-1) non-maximally entangled GHZ state particle pairs; the non-maximally entangled GHZ state particle pairs are represented as: Among them, a and b are unknown and satisfy |a| 2 +|b| 2 =1; L is the preset value;

[0010] The particle source is represented as: Where i = (1, 2, 3...L);

[0011] The first set of sequences is represented as:

[0012]

[0013] wherein the first group of sequences includes the first particles of all GHZ states of the sequence;

[0014] The second set of sequences is represented as:

[0015]

[0016] The second group of sequences includes the second and third particles of all GHZ states of the sequence.

[0017] In one embodiment of the present invention, the quantum state of the decoy photon randomly changes from

[0018] |0 dp >,|1 dp >,|+ dp >,|- dp >Select from four quantum states, where

[0019] In one embodiment of the present invention, the specific steps of determining the first error rate and obtaining a first determination result include:

[0020] If the first error rate is less than the first preset threshold, the first judgment result is that there is no eavesdropper, and the conference participant A j Remove the new second set of sequences The decoy photons in the The conference participant A j For the second set of sequences Perform Bell measurement to obtain a second measurement result, and encode the second measurement result to obtain a sequence Mj At the same time, the conference initiator Perform measurement to obtain a third measurement result, and encode the third measurement result to obtain the sequence M j , and the first set of sequences After measuring the collapse, we get the third set of sequences

[0021] If the first error rate is greater than or equal to the first preset threshold, the first judgment result is that there is an eavesdropper, all current operations are abandoned, and the conference initiator prepares non-maximally entangled GHZ state particle pairs, obtains a particle source based on the non-maximally entangled GHZ state particle pairs, and divides the particle source into (N-1) sequences S j , and each of the sequences S j Corresponding to one of the conference participants A j Each of the sequences includes a first set of sequences And the second set of sequences

[0022] In one embodiment of the present invention, the second measurement result is encoded to obtain a sequence M j The encoding rule in is expressed as follows: when the measurement result of particle B in the second measurement result is |00>+|11> or |00>-|11>, and the measurement of particle C fails, the sequence M j Marked as failed; when the measurement results of particles B and C in the second measurement result are both |01>+|10>, or the measurement results of particles B and C are both |01>-|10>, the sequence M j Marked as 10; when the measurement result of particle B in the second measurement result is |01>+|10> and the measurement result of particle C is |01>-|10>, or the measurement result of particle B is |01>-|10> and the measurement result of particle C is |01>+|10>, the binary sequence M j Marked as 11.

[0023] In one embodiment of the present invention, the third measurement result is encoded to obtain the sequence M j The encoding rules in are expressed as:

[0024] When the third measurement result is |00>+|11> or |11>-|11>, M j Mark as failed;

[0025] When the third measurement result is |01>+|10>, M j Marked as 10;

[0026] When the third measurement result is |01>-|10>, M j Marked as 11.

[0027] In one embodiment of the present invention, the conference initiator respectively generates the third group of sequences according to the shared key K. Perform Pauli operation to obtain the fourth set of sequences The Pauli operation rule in is expressed as:

[0028] When K=00, perform I operation;

[0029] When K=01, perform X operation;

[0030] When K=10, perform Z operation;

[0031] When K=11, perform Y operation;

[0032] Among them, the I operation is expressed as:

[0033] The X operation is represented as:

[0034] The Y operation is expressed as:

[0035] The Z operation is expressed as:

[0036] In one embodiment of the present invention, the new fourth set of sequences Sent to the corresponding conference participant A j And perform eavesdropping detection, and obtain the detection result in the specific steps of: Sent to the corresponding conference participant A j ; In each of the conference participants A j The fourth sequence is received After that, the conference initiator announces the new fourth group sequence The position of the decoy photon and the corresponding measurement basis; the conference participant A j According to the new fourth sequence announced by the conference initiator The position of the decoy photon and the corresponding measurement basis received by the new fourth set of sequences The fourth measurement result is measured to obtain the fourth measurement result, and the fourth measurement result is notified to the conference initiator; the conference initiator obtains the second error rate according to the fourth measurement result and the initial state of the decoy photon; if the second error rate is lower than the second preset threshold, the detection result is that there is no eavesdropper, and the new fourth group sequence The decoy photons in the image are removed, and the fourth sequence is obtained again. And each of the conference participants A j The fourth set of sequences received by oneself Measure and encode to get the sequence K j ; If the second error rate is higher than the preset limit value, the detection result is that there is an eavesdropper and execution is stopped.

[0037] In one embodiment of the present invention, each of the conference participants A j The fourth set of sequences received by oneself Measure and encode to get the sequence K j The coding rule is: when the conference participant A j For the fourth set of sequences When the measurement result is |00>+|11>, the sequence K j Marked as 00; when the conference participant A j For the fourth set of sequences When the measurement result is |00>-|11>, the sequence K j Marked as 01; when the conference participant A j For the fourth set of sequences When the measurement result is |01>+|10>, the sequence K j Marked as 10; when the conference participant A j For the fourth set of sequences When the measurement result is |01>-|10>, the sequence K j Marked as 11.

[0038] In one embodiment of the present invention, the shared key K is obtained according to the following formula:

[0039]

[0040] The above technical solution of the present invention has the following advantages compared with the prior art:

[0041] The beneficial effects of the present invention are as follows: the quantum conference key negotiation method with parameter-independent channels described in the present invention uses non-maximum entangled GHZ states and performs key negotiation through an entanglement exchange method, thereby solving the problem of cumbersome particle state preparation steps and improving computational efficiency; the present application can combat collective noise when using quantum channels for communication, does not need to know specific entangled state parameters when using quantum channels for transmission, and can avoid the influence of phase noise during transmission, thereby improving security and stability; the present application can simultaneously negotiate and reach a bilateral key between a conference initiator and a single participant and a conference key containing all users, and has a wider range of application value; the present application has guaranteed security and is safe for participants and external attacks, so that each participant can fairly participate in the negotiation of quantum keys. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of the overall flow of a quantum conference key agreement method with a parameter-independent channel provided for a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention and to be able to fully convey the scope of the present invention to those skilled in the art.

[0044] Reference Figure 1 As shown, a preferred embodiment of the present invention provides a quantum conference key negotiation method with a parameter-independent channel, including a conference initiator and (N-1) conference participants A participating in the quantum conference key negotiation. j (j=1,2,3…N-1); all participants have passed the identity authentication of the network center server;

[0045] Specifically, there are N participants, divided into Alice, the initiator of the meeting, and A, the participant of the meeting. j (j=1,2,3…N-1) participate in quantum key negotiation, and all participants have passed the identity authentication of the network center server.

[0046] In this embodiment, there are 10 participants Alice, A1, A2...A9 participating in the quantum conference key negotiation, and all participants have passed the identity authentication of the network center server, among which Alice is the conference initiator, and A1, A2...A9 are participants.

[0047] The method described in this application comprises the steps of:

[0048] S1, the conference initiator prepares non-maximally entangled GHZ state particle pairs, obtains particle sources based on non-maximally entangled GHZ state particle pairs, and divides the particle sources into (N-1) sequences S j , and each sequence S j Corresponding to a conference participant A j ; Each sequence includes the first group of sequences And the second set of sequences

[0049] Specifically, Alice, the conference initiator, prepares 2L×(N-1) non-maximally entangled GHZ state particle pairs. The non-maximally entangled three-qubit GHZ state with resistance to collective noise is expressed as:

[0050]

[0051] where a and b are unknown and satisfy |a| 2 +|b| 2 =1. Then As the particle source, where i = (1, 2, 3...L). These particles are divided into (N-1) sequences S j , each sequence corresponds to a participant, for example, S1 corresponds to A1, and then the particles in each sequence are divided into two groups:

[0052]

[0053]

[0054] Right now The first particle of all GHZ states of the particle sequence, Contains the second and third particles of all GHZ states of the particle sequence.

[0055] In this example, Alice prepares 2L×9 non-maximally entangled GHZ state particle pairs, expressed as where a and b are unknown and satisfy |a| 2 +|b| 2 =1(4). Then As the particle source, where i = (1, 2, 3...L). These particles are divided into 9 sequences S j , each sequence corresponds to a participant, and then the particles in each sequence are divided into two groups and The first particle of all GHZ states of the particle sequence, Contains the second and third particles of all GHZ states of the particle sequence.

[0056] S2, the conference initiator sends the first sequence Staying local, randomly inserting a preset number of decoy photons into the second sequence In the new second set of sequences And record the position and state of the inserted decoy photons;

[0057] Specifically, Alice, the conference initiator, sends the first set of sequences Stay local, and then for the second set of sequences Prepare enough decoy photons to randomly insert into the second sequence Generate a new second set of sequences And record the position and state of the inserted decoy photon, where the quantum state of the decoy photon will randomly change from |0 dp >,|1 dp >,|+ dp >,|- dp >Choose from four quantum states;

[0058] Among them, Z basis: |0>,|1>;

[0059] X-Base:

[0060] Logical Z-basis for immunity to collective phase noise: |0 dp >=|01>,|1 dp >=|10>;

[0061] Logical X-base for immunity to collective phase noise:

[0062] S3, the conference initiator sends the new second sequence Sent to the corresponding participant A j ; In each conference participant A j Confirm receipt of the new second set of sequences Afterwards, the meeting initiator announces the position of the decoy photon and the corresponding measurement basis;

[0063] Specifically, Alice, the conference initiator, sends the latest sequence Sent to the corresponding conference participant A j , in the meeting participant A j Confirmation of receipt of sequence Later, Alice, the initiator of the meeting, announced the position of the decoy photon and the corresponding measurement basis.

[0064] S4, Conference Participant A j According to the position of the decoy photon announced by the conference initiator and the corresponding measurement basis, the new second set of sequences received Perform measurement to obtain a first measurement result, and inform the conference initiator of the first measurement result; the conference initiator obtains a first error rate according to the first measurement result and the initial state of the decoy photon, and judges the first error rate to obtain a first judgment result;

[0065] Specifically, if the first error rate is less than the first preset threshold, the first judgment result is that there is no eavesdropper, and S5 is executed; if the first error rate is greater than or equal to the first preset threshold, the first judgment result is that there is an eavesdropper, all current operations are abandoned, and S1 is executed.

[0066] Specifically, the meeting participants measure the received sequence according to the position of the decoy photon announced by Alice and the corresponding measurement basis, and inform Alice of the measurement results. By comparing the measurement results with the initial state of the decoy photon, Alice can obtain the error rate; if the measurement result error rate is less than the given threshold, it indicates that there is no eavesdropper and the next step will be executed; otherwise, all previous operations will be abandoned and the negotiation protocol will be re-executed.

[0067] Among them, the Bell measurement after two pairs of three-qubit GHZ states are entangled is expressed as: (5)

[0068]

[0069] S5, Conference Participant A j Remove the new second set of sequences The decoy photons in the Meeting Participant A j For the second set of sequences Perform Bell measurement to obtain a second measurement result, and encode the second measurement result to obtain a sequence M j ; At the same time, the conference initiator Perform measurement to obtain a third measurement result, and encode the third measurement result to obtain a sequence M j , and the first set of sequences After measuring the collapse, we get the third set of sequences

[0070] Specifically, meeting participant A j Remove The decoy photons in the Then the sequence By performing Bell measurement and encoding the measurement results, a binary sequence M with a length of 2L bits can be obtained. j ,The encoding rules are shown in Table 1.

[0071] Table 1

[0072]

[0073] At the same time, Alice The measurement is performed and the measurement results are encoded. The encoding rules are shown in Table 2. Then M can also be obtained. j , then the sequence After measuring the collapse, it is recorded as

[0074] Table 2

[0075]

[0076]

[0077] In S5, each conference participant A j Both Alice and the conference initiator will generate the same sequence M j , and the sequence M j The lengths are different; at this time, Alice, the initiator of the meeting, and each participant A j There is a bit sequence M known only to both parties. j , where m i ={10,11}, and each conference participant A j According to its encoding M j Get the measurement results of Alice, the conference initiator.

[0078] S6, the conference initiator retains the sequence M it obtains j The result of successful measurement is obtained in the sequence And publish the sequence The minimum number of bits in L'; the conference initiator only retains The number of bits in the sequence is the value before L', and the sequence M' is obtained. j ; At the same time, each conference participant A j According to the minimum value L' announced by the conference initiator, the corresponding sequence M' is obtained in the same way j ;

[0079] Among them, the sequence M' j For the conference initiator and each conference participant A j Sequences shared between them separately;

[0080] Specifically, there are measurement failures in the previous measurement results, so the conference initiator Alice only retains all the M j The result of successful measurement is obtained turn up The minimum value L' of the number of bits in the meeting is announced, and then Alice, the initiator of the meeting, will send all Only keep the value before the bit number L' to get the sequence M' j Among them, due to the sequence M j The lengths are different, so this step will sequence M j The length is unified, and M' is obtained j .

[0081] At the same time, all conference participants A j According to the value of L' published by Alice, the initiator of the meeting, the sequence M obtained by yourself is obtained in the same way j By performing the operation, you can get your corresponding M' j .

[0082] In S6, Alice, the conference initiator, generates a j A secret key M' shared between j .

[0083] S7, the conference initiator randomly generates a sequence M' j Sequences of the same length K A , and according to the sequence K A and sequence M' j , get the conference initiator and conference participant A j The shared key K between them;

[0084] Alice, the conference initiator, randomly generates a binary bit with a length of 2L' and compares it with M' j A sequence of the same length as the key K A , and then calculate the value of the key K shared by all participants, where

[0085]

[0086] At this point, the conference initiator Alice has completed generating the key K shared by all participants.

[0087] S8, the conference initiator uses the shared key K to respectively Perform Pauli operation to obtain the fourth set of sequences The conference initiator is in the fourth group sequence A preset number of decoy photons are randomly added to obtain a new fourth sequence The new fourth sequence Sent to the corresponding conference participant A j And conduct eavesdropping detection and obtain detection results;

[0088] Specifically, the new fourth sequence Sent to the corresponding conference participant A j ; In each conference participant Aj Received the fourth sequence After that, the conference initiator announced the new fourth sequence The position of the decoy photons and the corresponding measurement basis;

[0089] Meeting Participant A j According to the new fourth series announced by the conference initiators The position of the decoy photon and the corresponding measurement basis receive the new fourth sequence Perform measurement to obtain a fourth measurement result, and inform the conference initiator of the fourth measurement result; the conference initiator obtains a second error rate according to the fourth measurement result and the initial state of the decoy photon;

[0090] If the second error rate is lower than the second preset threshold, the detection result is that there is no eavesdropper, and the new fourth sequence The decoy photons are removed and the fourth sequence is obtained again And each conference participant A j The fourth sequence I received Measure and encode to get the sequence K j ;

[0091] If the second error rate is higher than the preset limit value, the detection result is that there is an eavesdropper, and the execution is stopped.

[0092] Specifically, Alice, the conference initiator, generates a key K shared by all participants and shares it with each conference participant A. j After the separate keys are generated, the generated keys are distributed to each conference participant A j ;

[0093] Alice, the conference initiator, uses the key K to identify the sequence Perform operations to obtain a sequence The operation rules corresponding to K are shown in Table 3.

[0094] Table 3

[0095] K operate 00 I 01 X 10 Z 11 Y

[0096] Among them, the I operation is expressed as:

[0097] The X operation is represented as:

[0098] The Y operation is expressed as:

[0099] The Z operation is expressed as:

[0100] Alice, the conference initiator, is in sequence By randomly adding enough decoy photons, we get the sequence Similar to S3 and S4, the sequence Sent to the corresponding conference participant A j And perform eavesdropping detection. If the error rate is lower than the threshold, the decoy photons will be removed and the sequence will be restored. And continue with the subsequent steps, if the error rate is too high, terminate the protocol.

[0101] S9, each conference participant A j The fourth sequence I received Measure and encode to get the sequence K j ;

[0102] Specifically, when Alice, the conference initiator, informs each conference participant A j After the key is entered, each conference participant A j Perform measurement to obtain the key; each conference participant A j First, the received sequences The measurement and encoding are performed, and the encoding rules are shown in Table 4. Then, the conference initiator Alice and each participant A can be obtained. j Separate key K between the two parties j .

[0103] Table 4

[0104]

[0105] S10, each conference participant A j According to the sequence M' j and sequence K j Get the shared key K.

[0106] Specifically, each conference participant A j Calculate separately The value of can be calculated by formula (6), and the shared key K including all participants can be obtained.

[0107] In this application, there are N participants, of which Alice is the initiator of the meeting, A j (j=1,2…N-1) are the conference participants. Alice prepares 2L×(N-1) non-maximally entangled GHZ state particle pairs and divides these particles into (N-1) sequences, each sequence corresponds to a participant. Then the initiator divides the particles in each sequence into two groups and and will The quantum channel is sent to the participants of each sequence. After all participants perform Bell measurement on their own particles, they can obtain the M common to Alice and each participant. j Finally, Alice The operation is performed and sent to the corresponding participants through the quantum channel for Bell measurement, so all participants can obtain a j The mutual key K with Alice j and a shared key K that is equally shared by all participants.

[0108] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0109] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

[0110] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A quantum conference key negotiation method with a parameter-independent channel, characterized in that: Including a conference initiator and (N-1) conference participants A who participate in quantum conference key negotiation i (j=1, 2, 3...N-1); wherein all participants have passed the identity authentication of the network center server; the method comprises the steps of: The conference initiator prepares non-maximally entangled GHZ state particle pairs, obtains a particle source based on the non-maximally entangled GHZ state particle pairs, and divides the particle source into (N-1) sequences A i , and each of the sequences S i Corresponding to one of the conference participants A i Each of the sequences includes a first set of sequences And the second set of sequences The conference initiator sends the first set of sequences Staying in the local area, randomly inserting a preset number of decoy photons into the second set of sequences In the new second set of sequences and recording the position and state of the inserted decoy photons; The conference initiator sends the new second set of sequences Sent to the corresponding participant A i ; In each of the conference participants A i Acknowledge receipt of the new second set of sequences Afterwards, the conference initiator announces the position of the decoy photon and the corresponding measurement basis; The conference participant A i The new second set of sequences received based on the position of the decoy photons announced by the conference initiator and the corresponding measurement basis Performing measurement to obtain a first measurement result, and informing the conference initiator of the first measurement result; the conference initiator obtains a first error rate according to the first measurement result and the initial state of the decoy photon, and judges the first error rate to obtain a first judgment result; The conference participant A i Remove the new second set of sequences The decoy photons in the The conference participant A i For the second set of sequences Perform Bell measurement to obtain a second measurement result, and encode the second measurement result to obtain a sequence M i At the same time, the conference initiator Perform measurement to obtain a third measurement result, and encode the third measurement result to obtain the sequence M i , and the first set of sequences After measuring the collapse, we get the third set of sequences The conference initiator retains the sequence M obtained by it i The result of successful measurement is obtained in the sequence and publish the sequence The minimum number of bits L' in the conference initiator only retains the The number of bits in the sequence is the value before L', and the sequence M' is obtained. i ; At the same time, each of the conference participants A i According to the minimum value L' published by the conference initiator, the corresponding sequence M' is obtained in the same way i ; The conference initiator randomly generates a sequence M′ i Sequences of the same length K A , and according to the sequence K A and the sequence M′ i , get the conference initiator and the conference participant A i The shared key K between them; The conference initiator respectively performs a third sequence Perform Pauli operation to obtain the fourth set of sequences The conference initiator is in the fourth group sequence A preset number of decoy photons are randomly added to obtain a new fourth sequence The new fourth set of sequences Sent to the corresponding conference participant A i And conduct eavesdropping detection and obtain detection results; Each of the conference participants A i The fourth set of sequences received by oneself Measure and encode to get the sequence K i ; wherein the sequence K i For the conference initiator and each of the conference participants A i Separate keys between; Each of the conference participants A i According to the sequence M' i and the sequence K i Obtain the shared key K; The shared key K is obtained according to the following formula:

2. The quantum conference key negotiation method with parameter-independent channel according to claim 1 is characterized in that: The conference initiator prepares 2L×(N-1) non-maximally entangled GHZ state particle pairs; the non-maximally entangled GHZ state particle pairs are expressed as: Among them, a and b are unknown and satisfy |a| 2 +|b| 2 =1; L is the preset value; The particle source is represented as: Where i = (1, 2, 3, ... L); The first set of sequences is represented as: wherein the first group of sequences includes the first particles of all GHZ states of the sequence; The second set of sequences is represented as: The second group of sequences includes the second and third particles of all GHZ states of the sequence.

3. The quantum conference key negotiation method with parameter-independent channel according to claim 1 is characterized in that: The quantum state of the decoy photon randomly changes from |0 dp >,|1 dp >,|+ dp >,|- dp >Select from four quantum states, where |0 dp >=|01>,|1 dp >=|10>, 4. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: The specific steps of determining the first error rate and obtaining a first determination result include: If the first error rate is less than the first preset threshold, the first judgment result is that there is no eavesdropper, and the conference participant A i Remove the new second set of sequences The decoy photons in the The conference participant A i For the second set of sequences Perform Bell measurement to obtain a second measurement result, and encode the second measurement result to obtain a sequence M i At the same time, the conference initiator Perform measurement to obtain a third measurement result, and encode the third measurement result to obtain the sequence M i , and the first set of sequences After measuring the collapse, we get the third set of sequences If the first error rate is greater than or equal to the first preset threshold, the first judgment result is that there is an eavesdropper, all current operations are abandoned, and the conference initiator prepares non-maximally entangled GHZ state particle pairs, obtains a particle source based on the non-maximally entangled GHZ state particle pairs, and divides the particle source into (N-1) sequences S i , and each of the sequences S i Corresponding to one of the conference participants A i Each of the sequences includes a first set of sequences And the second set of sequences 5. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: The second measurement result is encoded to obtain a sequence M i The encoding rules in are expressed as: When the measurement result of particle B in the second measurement result is |00>+|11> or |00>-|11>, and the measurement of particle C fails, the sequence M i Mark as failed; When the measurement results of the B particles and the C particles in the second measurement result are both |01>+|10>, or when the measurement results of the B particles and the C particles are both |01>-|10>, the sequence M i Marked as 10; When the measurement result of particle B in the second measurement result is |01>+|10> and the measurement result of particle C is |01>-|10>, or the measurement result of particle B is |01>-|10> and the measurement result of particle C is |01>+|10>, the binary sequence M i Marked as 11.

6. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: The third measurement result is encoded to obtain the sequence M i The encoding rules in are expressed as: When the third measurement result is |00>+|11> or |11>-|11>, M i Mark as failed; When the third measurement result is |01>+|10>, M i Marked as 10; When the third measurement result is |01>-|10>, M i Marked as 11.

7. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: The conference initiator respectively performs a third sequence Perform Pauli operation to obtain the fourth set of sequences The Pauli operation rule in is expressed as: When K=00, perform I operation; When K=01, perform X operation; When K=10, perform Z operation; When K=11, perform Y operation; Among them, the I operation is expressed as: The X operation is represented as: The Y operation is expressed as: The Z operation is expressed as:

8. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: The new fourth set of sequences Sent to the corresponding conference participant A i And conduct eavesdropping detection, the specific steps of obtaining the detection results include: The new fourth set of sequences Sent to the corresponding conference participant A i ; In each of the conference participants A i The fourth sequence is received After that, the conference initiator announces the new fourth group sequence The position of the decoy photons and the corresponding measurement basis; The conference participant A i According to the new fourth sequence announced by the conference initiator The position of the decoy photon and the corresponding measurement basis received by the new fourth set of sequences Performing measurement to obtain a fourth measurement result, and informing the conference initiator of the fourth measurement result; the conference initiator obtains a second error rate according to the fourth measurement result and the initial state of the decoy photon; If the second error rate is lower than the second preset threshold, the detection result is that there is no eavesdropper, and the new fourth group sequence The decoy photons in the image are removed, and the fourth sequence is obtained again. And each of the conference participants A i The fourth set of sequences received by oneself Measure and encode to get the sequence K i ; If the second error rate is higher than a preset limit value, the detection result is that there is an eavesdropper, and the execution is stopped.

9. The quantum conference key negotiation method with parameter-independent channel according to claim 1, characterized in that: Each of the conference participants A i The fourth set of sequences received by oneself Measure and encode to get the sequence K i The encoding rules in are: When the conference participant A i For the fourth set of sequences When the measurement result is |00>+|11>, the sequence K i Marked as 00; When the conference participant A i For the fourth set of sequences When the measurement result is |00>-|11>, the sequence K i Marked as 01; When the conference participant A i For the fourth set of sequences When the measurement result is |01>+|10>, the sequence K i Marked as 10; When the conference participant A i For the fourth set of sequences When the measurement result is |01>-|10>, the sequence K i Marked as 11.

Images