A highly practically secure continuous-variable quantum secret sharing method

Abstract

This invention discloses a highly practically secure continuous-variable quantum secret sharing method, belonging to the field of quantum communication technology. Specifically, the method involves: First, establishing a communication scenario consisting of an untrusted measuring party, a distributor, and n participants; the n participants and the distributor prepare their respective quantum states and transmit them to the measuring party through a quantum channel; the measuring party performs Bell state measurements on the quantum states from the participants and the distributor and publishes the measurement results; then, the distributor and participants each randomly select a portion of the quantum state data and, combined with the publicly published measurement results from the measuring party, calculate the transmittance of all channels. Next, the distributor performs classical post-processing with each participant sequentially to obtain their respective keys; finally, the participants and the distributor verify the keys using a hash function. This invention, by having an untrusted third party perform quantum state measurements and publish the results, avoids security vulnerabilities caused by detector non-ideals.

Description

Technical Field

[0001] This invention relates to the field of quantum communication technology, and in particular to a highly practically secure method for sharing quantum secrets of continuous variables. Background Technology

[0002] In recent years, with the development of high-performance computing technology, the security of classical cryptography, based on computational complexity, has been greatly threatened. Quantum cryptography, an interdisciplinary field based on quantum physics and classical information theory, utilizes the principles of quantum physics to ensure unconditional security in communication processes, and has received widespread attention and research.

[0003] Quantum Secret Sharing (QSS) is a relatively practical multi-party quantum communication technology in which the dealer distributes its own secret share to the players through quantum means, and the latter need to cooperate with each other to recover the secret.

[0004] The earliest quantum secret-sharing protocol was first proposed by Hillery et al. in 1999 (Phys. Rev. A 59, 1829), which used GHz entangled states to achieve secure secret sharing. However, entanglement-based protocols face problems such as the difficulty in preparing entangled states, the complexity of experimental equipment, and the low tolerance for losses, which greatly affect their practicality.

[0005] In the realm of continuous variables, this problem was solved by Grice et al. in 2018 (Phys.Rev.A 100,02233). Instead of utilizing entanglement, they generated secure keys separately between the distributor and multiple participants, thereby achieving (n,n)-threshold quantum secret sharing. This improved tolerance to noise and losses, and can be extended to cases with a large number of participants, increasing the practicality of quantum secret sharing. Summary of the Invention

[0006] To overcome the vulnerability of existing continuous-variable quantum secret sharing technologies to detector attacks, this invention provides a highly practically secure continuous-variable quantum secret sharing method. The distributor and all participants prepare quantum states using quantum modules (including lasers, modulators, etc.) in a local secure station. An untrusted third party performs the quantum state measurement. Subsequently, the distributor performs classical post-processing with each participant and provides a verification mechanism for the finally recovered secure key. This method can resist hacker attacks targeting detectors by eavesdroppers and deceptive attacks by dishonest participants, thus improving the security of quantum secret sharing.

[0007] The specific steps of the highly practically secure continuous variable quantum secret sharing method are as follows:

[0008] Step 1: Set up a communication scenario consisting of an untrusted measurement party, a distribution party, and n participants;

[0009] The distributor and all participants are connected via a quantum channel, and the measuring party is also connected simultaneously;

[0010] The distributor and each participant prepare their own quantum states using lasers and modulators, respectively. All participants except the first participant add their quantum states to the channel using a highly asymmetric beam splitter. Finally, the quantum states from the distributor and all participants enter the 50:50 beam splitter of the measuring party, where the measuring party performs Bell state measurements.

[0011] Step 2: Each of the n participants prepares its own quantum state in its respective security station using a laser and a modulator, and couples them together to transmit the quantum state to the measuring party via a quantum channel;

[0012] Specifically:

[0013] First, the first participant P1 prepares the quantum state |x1+ip1> locally and sends it to the quantum channel;

[0014] Quantum state modulation includes Gaussian modulation and discrete modulation;

[0015] x1 and p1 follow a Gaussian distribution with mean 0 and variance V1, where i is the imaginary part of the complex number.

[0016] Then, the second participant P2 prepares the quantum state |x2+ip2> locally and couples it with the transmitted quantum state |x1+ip1> in the channel through a highly asymmetric beam splitter, and sends it to the quantum channel again.

[0017] Starting with the third participant, the steps of the second participant are repeated until all participants have completed the quantum state preparation process.

[0018] Finally, the measuring party receives the quantum states from all participants as follows:

[0019] Where T k It is the channel transmittance of the quantum state of the k-th participant transmitted in the channel.

[0020] Step 3: The distributor also prepares its own quantum state locally |x D +ip D > and transmit it to the measuring party via a quantum channel.

[0021] The channel transmittance of the quantum state transmitted by the distributor in the channel is T. D .

[0022] Step 4: The measuring party performs Bell state measurements on the quantum states from the participating party and the distributing party, and publishes the measurement results;

[0023] The measurement results are expressed as follows: and

[0024] x M and p M These are the results of two zero-difference probes performed on the measuring side.

[0025] Step 5: The distributor and the participant each randomly select a portion of quantum state data, and combine it with the publicly available measurement results x from the measuring party. M and p M Calculate the channel transmittance {T1,T2,...,T} n} and T D .

[0026] Step 6: The distributor performs classic post-processing with each participant in turn to obtain the keys of the distributor and all participants.

[0027] The specific steps are as follows:

[0028] Step 601: The distributor assumes that P1 is an honest participant and that the other participants are dishonest. Then, the distributor randomly selects a portion of the data and requests the other participants to disclose their corresponding raw data, while the measuring party discloses its measurement results.

[0029] Step 602: The distributor uses the publicly available results from the measurement party and the raw data from the other participants excluding P1 to calculate the estimated value {x} of participant P1. N ,p N};

[0030] Specifically:

[0031]

[0032] Step 603: The distributor uses its own quantum state to estimate the value {x} of P1. N ,p N The data is corrected to obtain the corrected data {x1′, p1′}.

[0033] The corrected formula is:

[0034] x1′=x D +k·x N p1′=p D -k·p N ;

[0035] in It is the magnification factor.

[0036] Step 604: The distributor and participant P1 use the original data {x1,p1} and the modified data {x1′,p1′} to perform parameter estimation, data coordination and private key amplification, and finally obtain the security key K1 of participant P1.

[0037] The security code rate corresponding to key K1 is R1;

[0038] Step 605: Return to step 601. The distributor selects the next participant as the honest participant. Repeat the above steps to finally obtain the independent keys {K1, K2, ..., K} for each of the n participants. n};

[0039] Choose the minimum of all security rates as the final security rate for all keys, i.e., R = min{R1, R2, ..., R...} n}

[0040] Step 606: The distributor performs an XOR operation on the n key strings to obtain the final security key. Each of the n participants holds a key, and only through cooperation can the final key be recovered.

[0041] Step 7: The participants and the distributors use a hash function to verify their respective final keys and compare the output results.

[0042] Specifically, all participants XOR their own keys and determine if they match the output of the distributor's K. If they do, the secure key is used as the communication key to transmit the secret. Otherwise, the key is discarded.

[0043] Compared with the prior art, the advantages of the present invention are:

[0044] 1) A highly practically secure continuous variable quantum secret sharing method employs a measurement device-independent approach, where an untrusted third party performs quantum state measurements and publishes the results. This approach can resist hacker attacks targeting the detector and avoids security vulnerabilities caused by detector non-ideality in quantum secret sharing.

[0045] 2) A highly practically secure continuous variable quantum secret sharing method uses a hash function to verify the final security key to resist deception attacks by dishonest participants, thereby further improving security. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the communication scenario constructed according to the present invention;

[0047] Figure 2 This is a flowchart of a highly practically secure continuous variable quantum secret sharing method according to the present invention. Detailed Implementation

[0048] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0049] This invention first establishes a measurement device-independent quantum secret sharing communication scenario, which includes an untrusted measuring party, a distributor, and n participants. The distributor and all participants prepare Gaussian-modulated coherent states using their respective lasers and modulators. Except for the first participant, the other participants add their coherent states to the channel through a highly asymmetric beam splitter. Finally, the coherent states from the distributor and all participants enter the measuring party's 50:50 beam splitter, where the measuring party performs Bell state measurements.

[0050] In the corresponding measurement-device-independent quantum secret-sharing method, the distributor and each participant generate independent keys using the measurement results disclosed by the measuring party. The distributor then XORs its n key strings to obtain the final key. Only through honest cooperation among the n participants can the final key be recovered.

[0051] like Figure 2 As shown, the specific steps are as follows:

[0052] Step 1: Set up a communication scenario consisting of an untrusted measurement party, a distribution party, and n participants;

[0053] like Figure 1 As shown, the distributor and all participants are connected via a quantum channel, and the measuring party is also connected simultaneously;

[0054] The distributor and each participant prepare their own quantum states using lasers and modulators, respectively. All participants except the first participant add their quantum states to the channel using a highly asymmetric beam splitter. Finally, the quantum states from the distributor and all participants enter the 50:50 beam splitter of the measuring party, where the measuring party performs Bell state measurements.

[0055] Step 2: Each of the n participants prepares its own quantum state in its respective security station using a laser and a modulator, and couples them together to transmit the quantum state to the measuring party via a quantum channel;

[0056] Specifically:

[0057] First, the first participant P1 prepares the quantum state |x1+ip1> locally and sends it to the quantum channel;

[0058] Quantum state modulation includes Gaussian modulation and discrete modulation;

[0059] x1 and p1 follow a Gaussian distribution with mean 0 and variance V1, where i is the imaginary part of the complex number. x represents the canonical component of the phase space “position”; p represents the canonical component of the phase space “momentum”.

[0060] Then, the second participant P2 prepares the quantum state |x2+ip2> locally and couples it with the transmitted quantum state |x1+ip1> in the channel through a highly asymmetric beam splitter, and sends it to the quantum channel again.

[0061] Starting with the third participant, the steps of the second participant are repeated n-1 times until all participants have completed the quantum state preparation process.

[0062] Finally, the measuring party receives the quantum states from all participants as follows:

[0063] Where T k It is the overall channel transmittance of the quantum state of the k-th participant in the channel, including the losses caused by the channel and the beam splitter.

[0064] Step 3: The distributor also prepares its own quantum state locally |x D +ip D > and transmit it to the measuring party via a quantum channel.

[0065] The overall channel transmittance of the quantum state transmitted by the distributor in the channel is T. D .

[0066] Step 4: The measuring party performs Bell state measurements on the quantum states from the participating party and the distributing party, and publishes the measurement results;

[0067] The measurement results are expressed as follows: and

[0068] x M and p M These are the results of two zero-difference probes performed on the measuring side.

[0069] Step 5: The distributor and the participant each randomly select a portion of quantum state data and publish it, combining it with the publicly published measurement results x from the measuring party. M and p M Calculate the total channel transmittance {T1,T2,...,T} n} and T D .

[0070] Publicly available data will be abandoned.

[0071] Step 6: The distributor performs classic post-processing with each participant in turn to obtain the keys of the distributor and all participants.

[0072] The specific steps are as follows:

[0073] Step 601: The distributor assumes that P1 is an honest participant and that the other participants are dishonest. Then, the distributor randomly selects a portion of the data and requests the other participants to disclose their corresponding raw data, while the measuring party discloses its measurement results.

[0074] Step 602: The distributor uses the publicly available results from the measurement party and the raw data from the other participants excluding P1 to calculate the estimated value {x} of participant P1. N ,p N};

[0075] Specifically:

[0076]

[0077]

[0078] Step 603: The distributor uses its own quantum state to estimate the value {x} of P1. N ,p N The data is corrected to obtain the corrected data {x1′, p1′}.

[0079] The corrected formula is:

[0080] x1′=x D +k·x N p1′=p D -k·p N ;

[0081] in It is the magnification factor.

[0082] Step 604: The distributor and participant P1 use the original data {x1,p1} and the modified data {x1′,p1′} to perform parameter estimation, data coordination and private key amplification, and finally obtain the same security key K1 as participant P1.

[0083] The security code rate corresponding to key K1 is R1;

[0084] Step 605: Return to step 601. The distributor selects the next participant as the honest participant. Repeat the above steps to finally obtain the independent keys {K1, K2, ..., K} for each of the n participants. n};

[0085] Choose the minimum of all security rates as the final security rate for all keys, i.e., R = min{R1, R2, ..., R...} n}

[0086] Step 606: The distributor performs an XOR operation on the n key strings to obtain the final security key. Each of the n participants holds a key, and only through cooperation can the final key be recovered.

[0087] Step 7: The participants and the distributors use a hash function to verify their respective final keys and compare the output results.

[0088] Specifically, all participants XOR their own keys and determine if they match the output of the distributor's K. If they do, the secure key is used as the communication key to transmit the secret. Otherwise, the key is discarded.

Claims

1. A highly practically secure continuous-variable quantum secret sharing method, characterized in that, The specific steps are as follows: Step 1: Set up a communication scenario consisting of an untrusted measurement party, a distribution party, and n participants; Step 2: Each of the n participants prepares its own quantum state in its respective security station using a laser and a modulator, and couples them together to transmit the quantum state to the measuring party via a quantum channel; Specifically: First, the first participant P1 prepares the quantum state |x1+ip1> locally and sends it to the quantum channel; x1 and p1 follow a Gaussian distribution with mean 0 and variance V1, where i is the imaginary part of the complex number; Then, the second participant P2 prepares the quantum state |x2+ip2> locally and couples it with the transmitted quantum state |x1+ip1> in the channel through a highly asymmetric beam splitter, and sends it to the quantum channel again; Starting with the third participant, the steps of the second participant are repeated until all participants have completed the quantum state preparation process. Finally, the measuring party receives the quantum states from all participants as follows: Where T k It is the channel transmittance of the quantum state of the k-th participant transmitted in the channel; Step 3: The distributor also prepares its own quantum state locally |x D +ip D >and transmit it to the measuring party via a quantum channel; The channel transmittance of the quantum state transmitted by the distributor in the channel is T. D ; Step 4: The measuring party performs Bell state measurements on the quantum states from the participating party and the distributing party, and publishes the measurement results; The measurement results are expressed as follows: and x M and p M These are the results of two zero-difference probes performed on the measuring side; Step 5: The distributor and the participant each randomly select a portion of quantum state data, and combine it with the publicly available measurement results x from the measuring party. M and p M Calculate the channel transmittance {T1,T2,...,T} n } and T D ; Step 6: The distributor performs classic post-processing with each participant in turn to obtain the keys of the distributor and all participants. The specific steps are as follows: Step 601: The distributor assumes that P1 is an honest participant and that the other participants are dishonest. Then, the distributor randomly selects a portion of the data and asks the other participants to disclose their corresponding original data, while the measuring party discloses its measurement results. Step 602: The distributor uses the publicly available results from the measurement party and the raw data from the other participants excluding P1 to calculate the estimated value {x} of participant P1. N ,p N }; Specifically: Step 603: The distributor uses its own quantum state to estimate the value {x} of P1. N ,p N The data is corrected to obtain the corrected data {x1′, p1′}. The corrected formula is: x1′=x D +k·x N ,p1′=p D -k·p N ; in It is the magnification factor; Step 604: The distributor and participant P1 use the original data {x1,p1} and the modified data {x1′,p1′} to perform parameter estimation, data coordination and private key amplification, and finally obtain the security key K1 of participant P1; The security code rate corresponding to key K1 is R1; Step 605: Return to step 601. The distributor selects the next participant as the honest participant. Repeat the above steps to finally obtain the independent keys {K1, K2, ..., K} for each of the n participants. n }; Choose the minimum of all security rates as the final security rate for all keys, i.e., R = min{R1, R2, ..., R...} n }; Step 606: The distributor performs an XOR operation on the n key strings to obtain the final security key. n participants each hold a string of keys, and only by cooperating with each other can the final key be recovered; Step 7: The participants and the distributors use a hash function to verify their respective final keys and compare the output results.

2. The highly practically secure continuous-variable quantum secret sharing method as described in claim 1, characterized in that, In step one, the distributor and all participants are connected through a quantum channel, and the measuring party is also connected simultaneously. The distributor and each participant prepare their own quantum states using lasers and modulators, respectively. All participants except the first participant add their quantum states to the channel using a highly asymmetric beam splitter. Finally, the quantum states from the distributor and all participants enter the 50:50 beam splitter of the measuring party, where the measuring party performs Bell state measurements.

3. The highly practically secure continuous-variable quantum secret sharing method as described in claim 1, characterized in that, In step two, quantum state modulation includes Gaussian modulation and discrete modulation.

4. A highly practically secure continuous-variable quantum secret sharing method as described in claim 1, characterized in that, Step seven specifically involves: n participants transferring their respective independent keys {K1, K2, ..., K...} n Perform an XOR operation and determine whether the result is the same as the security key K of the distributor. If so, use the security key as the communication key to transmit the secret. Otherwise, discard the key.

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