Advantageous reference frame independent quantum key distribution method

Abstract

The application discloses a reference system independent quantum key distribution method with advantage purification and belongs to the technical field of quantum secure communication. The method comprises the following steps: S1, quantum state preparation; S2, quantum state measurement; S3, base vector comparison; S4, parameter estimation; S5, advantage purification; and S6, post-processing. The sender of the quantum state and the sender of the quantum state perform key negotiation, error checking and secret amplification operation, and extract a secure key. The application can tolerate a larger error code, improve the secure key rate and transmission distance, and does not need additional physical equipment and can be directly applied to an actual reference system independent quantum key distribution system.

Description

Technical Field

[0001] This invention belongs to the field of quantum secure communication technology, and more specifically, relates to a reference frame-independent quantum key distribution method with superior purification. Background Technology

[0002] Quantum Key Distribution (QKD) technology enables unconditionally secure key sharing between two authenticated users in an information theory sense, providing a secure communication method based on quantum physics. Currently, QKD technology is rapidly advancing from the laboratory to commercialization, creating an urgent need for low system complexity and excellent performance. In practical systems, both communicating parties need to share a consistent reference frame to ensure normal system operation. Actively calibrating the reference frame reduces communication efficiency and increases system complexity. Reference-Frame-Independent QKD (RFI-QKD) protocols can generate secure keys even with slow reference frame drift, effectively reducing system complexity. However, the current secure key rate and transmission distance of RFI-QKD are still relatively low, leaving room for further improvement. Summary of the Invention

[0003] This invention proposes a reference frame-independent quantum key distribution method with superior purification, aiming to improve the security key rate and transmission distance of current reference frame-independent quantum key distribution systems.

[0004] To solve at least one of the above-mentioned technical problems, according to one aspect of the present invention, a reference frame-independent quantum key distribution method with superior purification is provided, comprising the following steps: S1, quantum state preparation;

[0005] S2, quantum state measurement;

[0006] S3, basis alignment;

[0007] S4. Parameter estimation;

[0008] S5, superior purification;

[0009] S6. Post-processing: The quantum state sender and the quantum state sender perform key negotiation, error checking and security amplification operations to extract the security key;

[0010] In S1 and S2, the basis vector ξ of the quantum state sender A ∈{Z A ,X A ,Y A} and the basis vector ξ of the receiver of the quantum state B ∈{Z B ,XB ,Y B Z satisfies the following relationship: A =Z B =Z,X B =X A cosβ+Y A sinβ,Y B =Y A cosβ-X A sinβ, where β represents the relative deflection of the reference frame between the sender and receiver of the quantum state; when using an ideal single-photon source, the ZZ-based bit error rate Q and the statistic R satisfy...

[0011] The formula for the security key rate obtained after executing S6 is as follows:

[0012]

[0013] And satisfy the following constraints

[0014]

[0015] q succ =(E μ ) b +(1-E μ ) b ,

[0016] p succ =(λ1+λ2) b +(λ3+λ4) b ,

[0017]

[0018] Q L ≤λ3+λ4≤Q U ,

[0019] R L ≤(λ1-λ2) 2 ≤R U ,

[0020]

[0021]

[0022]

[0023]

[0024] Where H(x) = -xlog2x - (1-x)log2(1-x) is the binary Shannon entropy function. Q is the probability of a single photon in the signal state. μ E is the total count rate of the Z-based signal states. μ It is the bit error rate of the Z-based signal state before the advantage purification stage. It is the bit error rate of the Z-based signal state after the advantage purification stage. It is the lower bound of the single-photon count rate in the Z-based system, Q L It is the lower bound of the single-photon bit error rate of the Z-based system, Q U R is the upper bound of the single-photon bit error rate of the Z-based system. L It is the lower bound of the statistic R, R U It is the upper bound of the statistic R, and f is the error correction efficiency.

[0025] Preferably, the specific steps for quantum state preparation in S1 are as follows: In each round, the sender of the quantum state randomly selects a bit a∈{0,1}, and the basis vector ξ A ∈{Z A ,X A ,Y A} and light intensity δ∈{μ,v,ω}; μ corresponds to the light intensity of the signal state, v corresponds to the light intensity of the decoy state, and ω corresponds to the light intensity of the vacuum state; prepare a quantum state; then the sender of the quantum state sends the quantum state to the receiver of the quantum state through a quantum channel.

[0026] Preferably, the specific steps of S2 are as follows: the receiver of the quantum state randomly selects the basis vector ξ. B ∈{Z B ,X B ,Y B} Measure the received quantum state and record the measurement results.

[0027] Preferably, the specific steps of S3 are as follows: After N rounds, the sender of the quantum state publishes the basis vector ξ through a certified classical channel. A And the intensity δ information, the receiver of the quantum state publishes the measurement basis vector ξ B Information; the sender and receiver of the quantum state classify their success events as Here, the subscript zz indicates that the sender of the quantum state is chosen by the basis vector Z. A The receiver of the quantum state chooses the basis vector Z. B The subscript xxyy indicates that the quantum state sender's choice basis vector X. A The receiver of the quantum state chooses the basis vector X. B And the quantum state sender selection basis Y A The receiver of the quantum state chooses the basis vector Y. B The subscript xyyx indicates the sender selection basis vector X of the quantum state. A The receiver of the quantum state chooses the basis vector Y. BAnd the quantum state sender selection basis Y A The receiver of the quantum state chooses the basis vector X. B And obtain the sieved key.

[0028] Preferably, S4 is as follows:

[0029] The sender and receiver of the quantum state randomly select a subset of bits from the sieved key for comparison, estimating the lower bound Y1 of the single-photon count rate under the ZZ basis vector. L The upper bound of the single-photon bit error rate Q under the ZZ basis vectors. U and the lower Q L The upper bound of the statistic R is R0. U and the lower bound R L .

[0030] Preferably, S5 specifically involves: the sender of the quantum state dividing its original key into bit blocks of size b {x1, x2, ..., x...} b The receiver of the quantum state divides its original key into a bit block of size b {y1,y2,…,y}. b The sender in the quantum state randomly selects a bit c∈{0,1} and transmits the message through an authenticated classical channel. The symbol is sent to the receiver of the quantum state. Represents a bit XOR operation; when When x1 and y1 are equal to {0,0,…,0} or {1,1,…,1}, use x1 and y1 as the original key; when... If the bit blocks are not equal to {0,0,…,0} or {1,1,…,1}, discard them.

[0031] According to another aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps in the reference frame-independent quantum key distribution method of the present invention with advantages of purification.

[0032] According to another aspect of the present invention, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement steps in the reference frame-independent quantum key distribution method with the advantages of the present invention.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] The present invention provides a superior reference-frame-independent quantum key distribution method to improve the security key rate and transmission distance of current reference-frame-independent quantum key distribution systems. Simulation results from actual systems show that, compared to conventional reference-frame-independent quantum key distribution methods, the superior method not only tolerates larger bit errors, improving its security key rate and transmission distance, but also requires no additional physical equipment and can be directly applied to practical reference-frame-independent quantum key distribution systems. Attached Figure Description

[0035] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0036] Figure 1 This is a flowchart of the method in Embodiment 1 of the present invention;

[0037] Figure 2 This is a performance simulation diagram of the system in Embodiment 1 of the present invention. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention.

[0039] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0040] like Figure 1-2 As shown,

[0041] Example 1:

[0042] A reference frame-independent quantum key distribution method with improved advantages includes the following steps:

[0043] This method involves two users, Alice and Bob, where Alice is the sender of the quantum state and Bob is the receiver of the quantum state. The specific execution process is as follows:

[0044] (1) Quantum state preparation: In each round, Alice randomly selects a bit a∈{0,1}, basis vector ξ A ∈{Z A ,X A ,Y AAlice then prepares a quantum state using light intensity δ∈{μ,ν,ω} (μ corresponds to the signal state light intensity, ν corresponds to the decoy state light intensity, and ω corresponds to the vacuum state light intensity). Alice then sends this quantum state to Bob via a quantum channel.

[0045] (2) Quantum state measurement: Bob randomly selects the basis vector ξ B ∈{Z B ,X B ,Y B} Measure the received quantum state and record the measurement results.

[0046] (3) Basis alignment: After N rounds, Alice publishes the basis ξ through the certified classical channel. A Bob released the measured basis vector ξ, along with the intensity δ information. B Information. Based on the information above, Alice and Bob categorized their successes as follows: Here, the subscript zz indicates that Alice chooses the basis vector Z. A Bob chooses basis vector Z B The subscript xxyy indicates that Alice chooses the basis vector X. A Bob chooses basis X B And Alice's choice of basis Y A Bob chooses basis Y B The subscript xyyx indicates that Alice chooses the basis vector X. A Bob chooses basis Y B And Alice's choice of basis Y A Bob chooses basis X B And obtain the filtered key.

[0047] (4) Parameter estimation: Alice and Bob randomly selected a portion of bits from the sieved key for comparison, estimating the lower bound Y1 of the single-photon count rate under the ZZ basis. L The upper bound of the single-photon bit error rate Q under the ZZ basis vectors. U and the lower Q L The upper bound of the statistic R is R0. U and the lower bound R L .

[0048] (5) Advantage Refinement: Alice divides her original key into bit blocks of size b {x1, x2, ..., x b Bob divides his original key into bit blocks of size b {y1, y2, ..., y}. b Alice randomly selects a bit c ∈ {0,1} and sends the message through an authenticated classic channel. Send to Bob (symbol) (Represents a bitwise XOR operation). When When the keys are {0,0,…,0} or {1,1,…,1}, they use x1 and y1 as the original keys. If the bit blocks are not equal to {0,0,…,0} or {1,1,…,1}, they are discarded.

[0049] (6) Post-processing: Alice and Bob perform key negotiation, error checking and security amplification operations to extract the security key.

[0050] In steps (1) and (2), Alice's basis vector ξ A ∈{Z A ,X A ,Y A} and Bob's basis vector ξ B ∈{Z B ,X B ,Y B Z satisfies the following relationship: A =Z B =Z,X B =X A cosβ+Y A sinβ,Y B =Y A cosβ-X A sinβ, where β represents the relative deflection of the reference frame between Alice and Bob; when using an ideal single-photon source, the ZZ-based bit error rate Q and the statistic R satisfy...

[0051] The formula for the security key rate obtained after performing step (6) is as follows:

[0052]

[0053] And satisfy the following constraints

[0054]

[0055] q succ =(E μ ) b +(1-E μ ) b ,

[0056] p succ =(λ1+λ2) b +(λ3+λ4) b ,

[0057]

[0058] Q L ≤λ3+λ4≤QU ,

[0059] R L ≤(λ1-λ2) 2 ≤R U ,

[0060]

[0061]

[0062]

[0063]

[0064] Where H(x) = -xlog2x - (1-x)log2(1-x) is the binary Shannon entropy function. Q is the probability of a single photon in the signal state. μ E is the total count rate of the Z-basis signal states (experimentally observable). μ It is the bit error rate (experimentally observable) of the Z-based signal state before the advantage purification stage. Y1 is the bit error rate of the Z-based signal state after the advantage purification stage. L It is the lower bound of the single-photon count rate in the Z-based system, Q L It is the lower bound of the single-photon bit error rate of the Z-based system, Q U R is the upper bound of the single-photon bit error rate of the Z-based system. L It is the lower bound of the statistic R, R U It is the upper bound of the statistic R, and f is the error correction efficiency.

[0065] The parameters used are as follows: single-photon detector detection efficiency of 40%, single-photon detector dark count rate of 10. -7 The fiber loss factor is 0.2 dB / km, the error correction code efficiency is 1.16, the system error floor is 1.5% and 3%, the reference frame deflection angle is π / 4, and the Alice transmit pulse number is 10. 11 The parameter estimation failure probability parameter is 10. -7 .

[0066] Example 2:

[0067] The computer-readable storage medium of this embodiment stores a computer program that, when executed by a processor, implements the steps in the reference frame-independent quantum key distribution method of Embodiment 1 with its advantages purified.

[0068] The computer-readable storage medium in this embodiment can be an internal storage unit of the terminal, such as the terminal's hard disk or memory; the computer-readable storage medium in this embodiment can also be an external storage device of the terminal, such as a plug-in hard disk, smart memory card, secure digital card, flash memory card, etc. equipped on the terminal; furthermore, the computer-readable storage medium can include both the terminal's internal storage unit and external storage devices.

[0069] The computer-readable storage medium of this embodiment is used to store computer programs and other programs and data required by the terminal. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0070] Example 3:

[0071] The computer device of this embodiment includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the reference frame-independent quantum key distribution method of Embodiment 1, which features improved purification.

[0072] In this embodiment, the processor can be a central processing unit, or other general-purpose processors, digital signal processors, application-specific integrated circuits, off-the-shelf programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The memory can include read-only memory and random access memory, and provides instructions and data to the processor. A portion of the memory can also include non-volatile random access memory. For example, the memory can also store device type information.

[0073] Those skilled in the art will understand that the content disclosed in the embodiments can be provided as a method, system, or computer program product. Therefore, this solution can take the form of a hardware embodiment, a software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this solution can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage) containing computer-usable program code.

[0074] This solution is described with reference to flowchart illustrations and / or block diagrams of methods and computer program products according to embodiments of this solution. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0075] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0076] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0077] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0078] The examples described herein are merely preferred embodiments of the invention and are not intended to limit the concept and scope of the invention. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the design concept of the invention should fall within the protection scope of the invention.

Claims

1. A reference frame-independent quantum key distribution method with superior purification, characterized in that, The method includes a sender of the quantum state and a receiver of the quantum state, and includes the following steps: S1, quantum state preparation; S2, quantum state measurement; S3, basis alignment; S4. Parameter estimation; S5, superior purification; S6. Post-processing: The quantum state sender and the quantum state sender perform key negotiation, error checking and security amplification operations to extract the security key; In S1 and S2, the basis vectors of the quantum state sender and the basis vectors of the receiver of the quantum state The following relationship must be satisfied: here This represents the relative deflection of the reference frame between the sender and receiver of the quantum state; When using an ideal single-photon source, the ZZ-based bit error rate Q and the statistic R satisfy... The formula for the security key rate obtained after executing S6 is as follows: （1） And satisfy the following constraints Where b represents: the sender Alice divides her original key into bit blocks of size b. The receiver, Bob, divides his original key into bit blocks of size b. That is, b is the size of the bit block; It is the binary Shannon entropy function. It is the probability of a single photon in the signal state. It is the total count rate of the Z-based signal states. It is the bit error rate of the Z-based signal state before the advantage purification stage. It is the bit error rate of the Z-based signal state after the advantage purification stage. It is the lower bound of the single-photon count rate under the Z-based system. It is the lower bound of the single-photon bit error rate based on the Z-base. It is the upper bound of the single-photon bit error rate of the Z-based system. It is the lower bound of the statistic R. It is the upper bound of the statistic R. It refers to error correction efficiency; ZZ basis refers to the sender-selective basis vector of the quantum state. The receiver of the quantum state chooses the basis vector. .

2. The method according to claim 1, characterized in that, The specific steps for preparing the quantum state in S1 are as follows: In each round, the sender of the quantum state randomly selects a bit. basis vectors and light intensity ; Corresponding signal state light intensity, Corresponding decoy state light intensity, Corresponding to the vacuum state light intensity; preparing a quantum state; then the sender of the quantum state sends the quantum state to the receiver of the quantum state through a quantum channel.

3. The method according to claim 1, characterized in that, The specific steps of S2 are as follows: the receiver of the quantum state randomly selects the basis vector. Measure the received quantum state and record the measurement results.

4. The method according to claim 1, characterized in that, The specific steps of S3 are as follows: After N rounds, the sender of the quantum state publishes the basis vector through a certified classical channel. and intensity Information, the receiver of the quantum state publishes the measurement basis vector. Information; the sender and receiver of the quantum state classify their success events as , , ; Subscript here The sender of the quantum state chooses the basis vector. The receiver of the quantum state chooses the basis vector. ; Subscript The sender's choice basis for representing the quantum state The receiver of the quantum state chooses the basis vector. And the sender selection basis vector of the quantum state The receiver of the quantum state chooses the basis vector. ; Subscript The sender's choice basis for representing the quantum state The receiver of the quantum state chooses the basis vector. And the sender selection basis vector of the quantum state The receiver of the quantum state chooses the basis vector. And obtain the filtered key.

5. The method according to claim 1, characterized in that, S4 specifically refers to: The sender and receiver of the quantum state randomly select a subset of bits from the sieved key for comparison, estimating the lower bound of the single-photon count rate under the ZZ basis vector. The upper bound of the single-photon bit error rate Q under the ZZ basis vectors and the lower realm and the upper bound of the statistic R. and the lower realm .

6. The method according to claim 1, characterized in that, S5 specifically involves the sender of the quantum state dividing its original key into bit blocks of size b. The receiver of the quantum state divides its original key into bit blocks of size b. The sender of the quantum state randomly selects a bit. And transmit the message through an authenticated classic channel. The symbol is sent to the receiver of the quantum state. Represents a bit XOR operation; when equal or At that time, and As the original key; when Not equal to or When this happens, these bit blocks are discarded.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the steps in the reference frame-independent quantum key distribution method with advantage purification as described in any one of claims 1 to 6.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the reference frame-independent quantum key distribution method with advantage purification as described in any one of claims 1 to 6.

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