Quantum key encryption communication method and system based on virtual private network

Abstract

The invention discloses a quantum key encryption communication method and system based on a virtual private network, relates to the technical field of data encryption transmission, and solves the technical problems that the existing quantum key online distribution is covered by an OKD network, the key providing capability and the key generation rate are far lower than the data transmission speed of a modern network, and the performance bottleneck exists. According to the method, the data of the virtual private network is transmitted and encrypted by taking online distribution of the quantum key as a main part and pre-charging as an auxiliary part; the data is encrypted by the online distributed quantum key or the pre-charged quantum key, so that the data security can be improved, and the performance bottleneck of an online distribution mode can be avoided; according to the application, when the key supply gap is made up in the pre-charging mode, the quantum key surplus in the key demand gap before the time range corresponding to the key supply gap and closest to the key supply gap is preferentially selected, and when pre-charging is carried out through the selected quantum key, due to the fact that the time from generation to use is short, the leakage risk can be greatly reduced.

Description

Technical Field

[0001] The present application relates to the field of data encryption transmission, and specifically to a quantum key encryption communication method and system based on a virtual private network. Background Art

[0002] A Virtual Private Network (VPN) is a technology that establishes a secure connection through a public network. It creates an encrypted channel between the user and the target network. A VPN must rely directly on an Internet service provider, and enterprises cannot directly control the VPN. Although VPNs have improved data security to a certain extent, there is still a risk of being attacked. Moreover, with the development of quantum computers, the possibility of traditional encryption algorithms being quickly cracked increases. In order to further enhance the security of data transmission, quantum encryption technology is increasingly being used in data encryption.

[0003] From the perspective of data security, online distribution technology of quantum keys is widely used. Online distributed quantum keys are more secure and have a short life cycle. They are generally generated when a session is established and destroyed when the session ends. Even if the key is leaked, the direct loss will not be too great. However, online distribution of quantum keys is limited by the coverage of the OKD network and the key provision capability. The key generation rate is usually limited to the Mbps level, which is much lower than the data transmission speed of modern networks, and there is a performance bottleneck.

[0004] The present application provides a quantum key encryption communication method and system based on a virtual private network to solve the above-mentioned technical problems. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art; to this end, the present application proposes a quantum key encryption communication method and system based on a virtual private network, which is used to solve the technical problem that the existing online distribution of quantum keys is limited by the coverage and key provision capabilities of the OKD network, and the key generation rate is usually limited to the Mbps level, which is far lower than the data transmission speed of modern networks, and there is a performance bottleneck.

[0006] To achieve the above-mentioned purpose, the first aspect of the present application provides a quantum key encryption communication method based on a virtual private network, which is applied to an encryption gateway in the virtual private network, and the encryption gateway is connected to a secure storage medium, including:

[0007] Predicting the amount of keys required for virtual private network data transmission based on data transmission records; and obtaining the amount of key supply generated by the quantum key distribution network per unit time;

[0008] The key supply gap of the virtual private network is calculated according to the predicted key amount and the key supply amount, and the quantum key is stored in a secure storage medium in advance by pre-filling to supplement the key supply gap.

[0009] Preferably, predicting the predicted amount of keys required for data transmission over the virtual private network includes:

[0010] Obtaining data transmission records of the virtual private network, and extracting characteristic data from the data transmission records; wherein the characteristic data includes timestamp, data transmission volume, user activity and network traffic;

[0011] Preprocessing the feature data to obtain a training data set; training a machine learning model constructed by the training data set to obtain a prediction model; wherein the preprocessing includes data cleaning and normalization processing, and the machine learning model refers to an artificial intelligence model suitable for time series prediction;

[0012] The data transmission volume of the virtual private network is predicted based on the prediction model, and the key prediction volume is calculated according to the data transmission volume.

[0013] Preferably, the step of obtaining the key supply amount generated by the quantum key distribution network per unit time includes:

[0014] By formula Calculate the key generation rate R of the quantum key distribution network; where η is the basis efficiency, QBER is the quantum bit error rate, and (1-2QBER) is the effective bit rate remaining after taking into account the bit error rate;

[0015] The key generation rate is multiplied by the unit time to obtain the key supply amount; wherein the unit time includes 1 second, 10 seconds or one minute.

[0016] Preferably, calculating the key supply gap of the virtual private network includes:

[0017] Establishing a key prediction function according to the key prediction amount, and constructing a key generation function according to the key supply amount; wherein the independent variables of the key prediction function and the key generation function are time;

[0018] The key prediction function and the key generation function are constructed as an objective function according to the key supply and demand relationship, and the objective function is solved to obtain the key supply gap corresponding to the objective function; wherein the key supply gap refers to that the key prediction amount is greater than the key supply amount.

[0019] Preferably, constructing the objective function includes:

[0020] The key prediction function is marked as f(t), and the key generation function is marked as g(t);

[0021] Based on the key prediction function and the key generation function, an objective function is constructed according to the key supply and demand relationship, and the objective function is: H(t)=f(t)-g(t); wherein t is time.

[0022] Preferably, solving the objective function includes:

[0023] The function value of the objective function is set to 0, and a number of zero points are obtained; adjacent zero points among the number of zero points are combined into time periods, and a number of time periods are obtained;

[0024] Determine whether the function value of the objective function in each time period is greater than 0; if yes, mark the corresponding time period as a key supply gap, otherwise mark it as a key demand gap.

[0025] Preferably, the quantum key is stored in advance in a secure storage medium by pre-filling, including:

[0026] Taking the time period corresponding to the key supply gap as the integration region, integrating the objective function to obtain the key gap amount;

[0027] The remaining keys of the key demand gap before the key supply gap are pre-filled into a secure storage medium to fill the key supply gap; wherein the number of remaining keys is greater than or equal to the key gap amount.

[0028] Preferably, pre-filling the remaining key into the secure storage medium comprises:

[0029] Constructing secondary functions based on the objective function Among them, i is the number of the key demand gap. The smaller i is, the later the corresponding time range is. The time period corresponding to the key demand gap is [Ti d , Ti u ];

[0030] Mark the key gap amount as MQL and solve the formula The time range corresponding to the remaining keys is obtained, and the remaining keys within the time range are injected into the secure storage medium.

[0031] Preferably, when data is transmitted through the virtual private network, the encryption gateway performs encrypted transmission using a quantum key generated online or a quantum key pre-filled in the secure storage medium.

[0032] The second aspect of the present application provides a quantum key encryption communication system based on a virtual private network, comprising:

[0033] A virtual private network, and encryption gateways at both ends of the virtual private network;

[0034] The encryption gateway encrypts the data to be transmitted by using a quantum key;

[0035] The encryption gateway is connected to a secure storage medium, and the secure storage medium is used to store the pre-filled quantum key.

[0036] Compared with the prior art, the beneficial effects of this application are:

[0037] This application mainly uses online distribution of quantum keys and pre-filling as a supplement to encrypt data transmission in a virtual private network; when the quantum keys distributed online cannot meet the data encryption requirements, sufficient quantum keys are pre-filled into a secure storage medium by prediction; encrypting data with quantum keys distributed online or pre-filled quantum keys can not only improve data security, but also avoid the performance bottleneck of the online distribution method.

[0038] When the present application fills the key supply gap by pre-filling, priority is given to selecting the quantum keys that are surplus to the key demand gap that is closest to the time range corresponding to the key supply gap. When the selected quantum keys are pre-filled, the time from generation to use is short, which can greatly reduce the risk of leakage and thus improve data security. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is a flow chart of the method for quantum key encryption communication in Example 1 of the present application;

[0041] Figure 2 Schematic diagram of the curve of the objective function G(t) in the first embodiment of the present application. DETAILED DESCRIPTION

[0042] The technical solution of the present application will be described clearly and completely in conjunction with the embodiments below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0043] Quantum encryption technology is widely used in the data encryption process due to its outstanding advantages in encryption. The sender encrypts the data to be encrypted through the quantum key, and then the receiver decrypts the encrypted data to obtain the required data. The data encrypted by the quantum key provides unconditional security based on physics, which can ensure the security of encrypted data even if the computer power is greatly improved in the future. Moreover, quantum key distribution can detect any attempt to eavesdrop in real time. Due to the non-cloning of quantum states, any interference with quantum bits will be detected by both parties to the communication, so that measures can be taken immediately to protect the security of communication.

[0044] A virtual private network (VPN) is a technology that establishes a secure connection through a public network (such as the Internet). It creates an encrypted tunnel between the user and the target network, through which data is transmitted to ensure the privacy and security of the data. VPN uses tunneling technology to establish a logical dedicated data channel on a public network. The data is encrypted and encapsulated in a new data packet at the sending end, transmitted through the public network, and then decapsulated and decrypted at the receiving end. However, although VPN has improved the security of data transmission to a certain extent, there is still a risk of being attacked, such as account sharing, forced logout at login time, etc. Therefore, using quantum encryption technology to encrypt data transmitted by VPN to improve data security has become a new trend.

[0045] There are two main ways to distribute quantum keys: online and offline. In the online key distribution mode, the quantum key generated by the quantum key distribution (QKD) network is directly provided to the encryption device, which is more secure, requires less modification to the encryption system, and is highly reproducible. However, there is a performance bottleneck, that is, the number of quantum keys provided in a short period of time is limited. In the offline key distribution mode, it is not restricted by the QKD network, and the required QKD network cost is lower, but because it involves the transmission and storage of quantum keys, it increases the risk of eavesdropping and affects data security.

[0046] A virtual private network connects users and the public network. The security of data is very important, and data security is also very important. This application provides a quantum key encryption communication method based on a virtual private network to take into account both security and encryption capabilities.

[0047] Embodiment 1: This embodiment provides a data transmission encryption service for a virtual private network, which is mainly based on online quantum key distribution and supplemented by offline distribution. It can ensure data security and break through the performance bottleneck of online quantum key distribution.

[0048] See also Figure 1, the first aspect of the present application provides a quantum key encryption communication method based on a virtual private network, which is applied to an encryption gateway in the virtual private network, and the encryption gateway is connected to a secure storage medium, including: predicting the key prediction amount required for virtual private network data transmission based on data transmission records; and obtaining the key supply amount generated by the quantum key distribution network in unit time;

[0049] The key supply gap of the virtual private network is calculated based on the predicted key quantity and the key supply quantity, and the quantum key is stored in a secure storage medium in advance through pre-filling to supplement the key supply gap.

[0050] The quantum key encryption communication method provided in this embodiment is mainly used for encryption gateways, that is, related services are integrated in the encryption gateway, and the online distribution of quantum keys and data encryption can be realized through the encryption gateway. In a virtual private network, there are generally at least two encryption gateways, one for encrypting the data at the sender and the other for decrypting the data received by the receiver. In some other preferred embodiments, an encryption gateway can also be set up to isolate the internal network from the public network to ensure the security of internal data.

[0051] The performance bottleneck of online quantum key distribution mainly refers to the fact that the key generation efficiency cannot meet the number of keys required for data encryption. To solve the performance bottleneck, enough quantum keys are needed for data encryption. Ensuring data security on this basis is the technical problem to be solved in this embodiment.

[0052] First determine how many quantum keys are needed for data transmission in the virtual private network to determine whether there is a performance bottleneck in the online distribution of quantum keys. This embodiment predicts the predicted amount of keys required for data transmission in the virtual private network based on data transmission records, specifically including the following steps:

[0053] Data collection: Collect VPN data transmission records, which mainly include timestamps, data transmission volume, user activities, network traffic and other factors that can reflect or affect data transmission volume;

[0054] Feature extraction: Extract useful features from data transmission records, such as total duration, total number of packets, total packet length, average sending interval, total sending time interval, etc.; use the extracted features as training data sets after preprocessing;

[0055] Model construction: define the LSTM (Long Short-Term Memory) network structure, including the number of hidden layers and neurons; train the defined LSTM using a training data set, and perform hyperparameter tuning, such as learning rate, batch size, number of iterations, etc.; in some other preferred embodiments, other artificial intelligence models suitable for time series prediction may also be used, such as support vector machine models, random forest models, etc.;

[0056] Predict data transmission volume: Predict data transmission volume by inputting future time periods or trend features into the trained LSTM.

[0057] There are many existing methods for predicting future data transmission volume based on data transmission records. Of course, you can also use existing public technical solutions for predicting future network (virtual private network) data transmission volume, and you don't have to be limited to the technical solutions given in this embodiment.

[0058] After the data transmission volume of the virtual private network is predicted, the number of quantum keys required for the data transmission volume can be determined according to the set quantum key distribution method, that is, the predicted key volume for virtual private network data transmission is predicted. It should be noted that this embodiment does not limit the quantum key distribution method, and a quantum key can be assigned to each data packet or to each user.

[0059] After predicting the number of quantum keys required by the virtual private network, it is also necessary to know how many quantum keys the quantum key distribution network can generate per unit time. In this embodiment, obtaining the key supply amount generated by the quantum key distribution network per unit time includes:

[0060] By formula Calculate the key generation rate R of the quantum key distribution network; where η is the basis efficiency, QBER is the quantum bit error rate, (1-2QBER) is the effective bit rate remaining after taking into account the bit error rate, For protocol efficiency, the protocol efficiency of BB84 protocol is usually taken as 0.5; multiplying the key generation rate by the set unit time can obtain the number of keys generated per unit time, that is, the key supply.

[0061] It should be considered that the key generation rate is actually the number of quantum keys generated per unit time. The unit time in this application is artificially set. Therefore, when calculating the key generation amount through the key generation rate, the relationship between the corresponding unit times of the two needs to be considered.

[0062] The above key supply calculation formula is a simplified formula, and many factors are not considered or are considered as fixed values. This embodiment also provides a calculation method with more accurate calculation results, and the specific steps are as follows:

[0063] Step 1: Determine system parameters;

[0064] q is the protocol efficiency, which is usually q=0.5 for the BB84 protocol;

[0065] Y μμ′ is the successful event response rate when both Alice and Bob send single photons encoded in the same basis;

[0066] Qμμ′ is the response rate under a given signal state;

[0067] E μμ′ is the bit error rate under a given signal state;

[0068] f(E μμ′ ) is the error correction efficiency function, which depends on the bit error rate E μμ′ ;

[0069] H2(x) is the binary entropy function, defined as H2(x)=-xlog2(x)-(1-x)log2(1-x).

[0070] Step 2: Calculate the amount of information leakage;

[0071] Information leakage I AE The phase error rate e p Estimate, using the binary Shannon entropy function H(e p )calculate.

[0072] Step 3: Security correction;

[0073] The security correction factor Δ takes into account potential side channel attacks and imperfections in the quantum channel. Its value is usually less than 1. It reduces the theoretical key generation rate to ensure security.

[0074] Step 4: Substitute into the GLLP formula:

[0075] The formula for calculating the key generation rate R is: R≥Δ·{max(q[-Q μμ′ f(E μμ′ )H2(E μμ′ )+G1[1-H2(e1)]],0)}; The key generation rate R at this time is the result after taking security correction into consideration.

[0076] After the predicted key quantity and the key supply quantity are determined, the relationship between the two at each time can be calculated, and then the key supply gap can be calculated. This embodiment provides a method for calculating the key supply gap of a virtual private network, including:

[0077] Taking time as the independent variable and the key prediction amount as the dependent variable, a key prediction function is established; taking time as the independent variable and the key supply amount as the dependent variable, a key generation function is established;

[0078] According to the key supply and demand relationship, the key prediction function and the key generation function can be combined to construct the objective function. Solving the objective function can obtain the key supply gap.

[0079] The key supply and demand relationship refers to the relationship between the key demand and key supply of a virtual private network at the same time, which can be converted into the relationship between the key prediction and key supply. Therefore, through the objective function, we can know whether the key is surplus or insufficient at a certain moment, laying a theoretical foundation for the subsequent key pre-filling.

[0080] The objective function is constructed to establish a relationship between the key prediction amount and the key supply amount. The objective function can be constructed by referring to the following steps:

[0081] The key prediction function is marked as f(t), and the key generation function is marked as g(t); based on the key prediction function and the key generation function, an objective function is constructed according to the key supply and demand relationship, and the objective function is: H(t) = f(t) - g(t); where t is time.

[0082] See also Figure 2 , the horizontal axis is the time axis, and the vertical axis is H(t). When the value of H(t) is greater than 0, according to the definition of the objective function, it can be seen that the demand for quantum keys at the corresponding time is greater than the supply of quantum keys, that is, the continuous time period corresponding to the area above the horizontal axis is the key supply gap. Similarly, the continuous time period corresponding to the area below the horizontal axis is the key demand gap.

[0083] The key prediction function is used to represent the relationship between the predicted key quantity (key demand) and time in the future of the virtual private network, and the key generation function refers to the relationship between the key supply quantity distributed online by the quantum key distribution network and time in the future. It can be understood that if the quantum key distribution network does not change, the number of quantum keys generated per unit time can be regarded as a fixed value, that is, the key generation function is a straight line parallel to the time axis.

[0084] The objective function is expressed as demand minus supply. If the objective function is greater than 0, it means that the demand is greater than the supply, and the supply is insufficient, which will form a key supply gap. Similarly, if the objective function is less than 0, it means that the demand is less than the supply, and the demand is insufficient, which will form a key demand gap. The steps to solve the objective function are as follows:

[0085] Let the function value of the objective function be 0, and obtain a number of zero points; combine adjacent zero points among the number of zero points into time periods, and obtain a number of time periods; determine whether the function value of the objective function in each time period is greater than 0; if yes, mark the corresponding time period as a key supply gap, otherwise mark it as a key demand gap.

[0086] Following the technical solution of this embodiment, when demand is insufficient and supply is sufficient, the ability of the quantum key distribution network to generate quantum keys online should be maintained, and the excess quantum keys should be stored in a pre-filled manner to fill the subsequent key supply gap. Since the storage capacity of the pre-filled quantum keys is much smaller than that of the offline distribution method, it is possible to achieve sufficient supply of quantum keys while effectively reducing the cost of storing quantum keys.

[0087] Storing quantum keys in a secure storage medium in advance by pre-filling means using the surplus quantum keys in the front to supplement the quantum key supply gap in the back, so that under the capacity of the existing quantum key distribution network, it is possible to ensure that there are enough quantum keys available in each time period. Therefore, it is necessary to first use the time period corresponding to the key supply gap as the integration area, integrate the objective function to obtain the key gap amount, that is, the number of quantum keys that still need to be supplemented on the basis of the quantum key distribution network providing quantum keys online corresponding to the key supply gap. The surplus quantum keys before the start time of the above-mentioned integration area are supplemented according to the key gap amount.

[0088] It is worth noting that the quantum key can directly encrypt the data, or it can be used in combination with an encryption algorithm (such as a symmetric encryption algorithm, an asymmetric encryption algorithm), that is, the encryption algorithm used by the quantum key encryption, so as to improve the encryption efficiency. Whether it is directly encrypting the data or the encryption algorithm used for encryption, the generation of the quantum key will have a performance bottleneck, so the present embodiment scheme is applicable to the above two encryption methods. The data recorded in this application is encrypted by the quantum key, and the data solved can be the data to be transmitted itself if the scene permits, and of course it can also be the data encrypted by the encryption algorithm. The encryption behavior of the quantum key in this application can be understood by referring to the existing scheme that the quantum key is encrypted twice on the basis of the encryption algorithm.

[0089] Embodiment 2: Based on the technical solution disclosed in Embodiment 1, the pre-filled and stored quantum key is limited in time, that is, the time from the generation, pre-filling and use of the quantum key is shortened as much as possible, which can reduce the risk of quantum key leakage and improve data security.

[0090] This embodiment provides a method for pre-filling a remaining key into a secure storage medium, including:

[0091] Constructing secondary functions based on the objective function Among them, i is the number of the key demand gap. The smaller i is, the later the corresponding time range is. The time period corresponding to the key demand gap is [Ti d , Ti u ];

[0092] Mark the key gap amount as MQL and solve the formula The time range corresponding to the remaining keys is obtained, and the remaining keys within the time range are injected into the secure storage medium.

[0093] Since H(t) = f(t) - g(t), that is, the difference between the quantum key demand and the quantum key supply when the virtual private network is transmitting data, and the integral value of H(t) in the time period corresponding to the key demand gap represents the difference between the quantum key supply and the quantum key demand, the result obtained by integrating the time is the surplus quantum key. In theory, the surplus quantum key can fill the quantum key supply gap.

[0094] As mentioned above, the key gap can be obtained by integrating the objective function, that is, the number of surplus quantum keys needs to be greater than the key gap. Therefore, a secondary function is constructed based on the objective function. It refers to the integration of the time period corresponding to the i-th key demand gap, that is, obtaining the surplus quantum keys in the time period. When the sum of the surplus quantum keys of multiple key demand gaps is greater than the key gap amount, the integral value without the absolute value sign should also be a positive value.

[0095] The specific key demand gaps can be solved by solving the constructed inequality Assuming that the time period corresponding to the key supply gap is j, the time period corresponding to i is before j, that is, the remaining keys of the key demand gap before the key supply gap are pre-filled. Moreover, the smaller the value of i, the closer the distance between its corresponding time period and the corresponding time period of j on the time axis. The solution process of the above inequality is actually to calculate which of the key demand gaps closest to j have surplus quantum keys that can fill the key gap amount corresponding to the key supply gap corresponding to j.

[0096] For example, suppose that the value of H(t) and the time axis in time period 1 is less than 0, the value in time period 2 is equal to 0, the value in time period 3 is less than 0, the value in time period 4 is equal to 0, and the value in time period 5 is greater than 0. This means that the key demand in time period 5 is greater than the key supply, and this part of the key gap needs to be supplemented by the surplus quantum keys in time period 1 and time period 3. If the surplus quantum keys in time period 3 are exactly equal to the key gap in time period 5, the surplus quantum keys in time period 3 are stored in a secure storage medium by pre-filling; if the surplus quantum keys in time period 3 are not enough to make up for the key gap in time period 5, the surplus quantum keys in time period 3 and time period 1 are combined to make up for the key gap in time period 5. It should be noted that no matter when the pre-filled keys are used, the quantum keys generated at the time closest to time period 5 should be given priority to, which can reduce the risk of leakage of the pre-filled quantum keys. The above process is also an inequality. The solution logic.

[0097] In addition to calculating which quantum keys with surplus key demand gaps are needed, the construction of the secondary function also considers that the quantum keys closest to the key supply gap should be selected to avoid storing the pre-filled quantum keys in the secure storage medium for too long, which is prone to leakage risks, that is, reducing the security of quantum key encryption. It can be understood that if there are multiple key supply gaps, the quantum keys with surplus key demand gaps before the corresponding time can be shared.

[0098] In this way, when data is transmitted through a virtual private network, the encryption gateway uses the quantum key generated online or the quantum key pre-filled in the secure storage medium for encrypted transmission. If the quantum key generated online is sufficient, it will be used. If not, the quantum key pre-filled in the secure storage medium will be extracted, and the data will be encrypted with the quantum key before transmission, thereby improving data security.

[0099] The second aspect of the present application provides a quantum key encryption communication system based on a virtual private network, including: a virtual private network, and encryption gateways at both ends of the virtual private network; the encryption gateway encrypts the data to be transmitted through a quantum key; the encryption gateway is connected to a secure storage medium, and the secure storage medium is used to store pre-charged quantum keys.

[0100] The above embodiments are only used to illustrate the technical method of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical method of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present application.

Claims

1. A quantum key encryption communication method based on a virtual private network, applied to an encryption gateway in a virtual private network, wherein the encryption gateway is connected to a secure storage medium, and characterized in that: include: Predicting the amount of keys required for VPN data transmission based on data transmission records; and, obtaining the key supply amount generated by the quantum key distribution network per unit time; The key supply gap of the virtual private network is calculated according to the predicted key amount and the key supply amount, and the quantum key is stored in a secure storage medium in advance by pre-filling to supplement the key supply gap.

2. The virtual private network-based quantum key encryption communication method according to claim 1, characterized in that: Predicting the amount of keys required for data transmission over the virtual private network includes: Obtaining data transmission records of the virtual private network, and extracting characteristic data from the data transmission records; wherein the characteristic data includes timestamp, data transmission volume, user activity and network traffic; Preprocessing the feature data to obtain a training data set; training a machine learning model constructed by the training data set to obtain a prediction model; wherein the preprocessing includes data cleaning and normalization processing, and the machine learning model refers to an artificial intelligence model suitable for time series prediction; The data transmission volume of the virtual private network is predicted based on the prediction model, and the key prediction volume is calculated according to the data transmission volume.

3. The virtual private network-based quantum key encryption communication method according to claim 1, characterized in that: The obtaining of the key supply amount generated by the quantum key distribution network per unit time comprises: By formula Calculate the key generation rate R of the quantum key distribution network; where η is the basis efficiency, QBER is the quantum bit error rate, and (1-2QBER) is the effective bit rate remaining after taking into account the bit error rate; The key generation rate is multiplied by the unit time to obtain the key supply amount; wherein the unit time includes 1 second, 10 seconds or one minute.

4. The virtual private network-based quantum key encryption communication method according to claim 1, characterized in that: Calculating the key supply gap of the virtual private network includes: Establishing a key prediction function according to the key prediction amount, and constructing a key generation function according to the key supply amount; wherein the independent variables of the key prediction function and the key generation function are time; The key prediction function and the key generation function are constructed as an objective function according to the key supply and demand relationship, and the objective function is solved to obtain the key supply gap corresponding to the objective function; wherein the key supply gap refers to that the key prediction amount is greater than the key supply amount.

5. The virtual private network-based quantum key encryption communication method according to claim 4, characterized in that: Constructing the objective function includes: The key prediction function is marked as f(t), and the key generation function is marked as g(t); Based on the key prediction function and the key generation function, an objective function is constructed according to the key supply and demand relationship, and the objective function is: H(t)=f(t)-g(t); wherein t is time.

6. The virtual private network-based quantum key encryption communication method according to claim 5, characterized in that: Solving the objective function includes: The function value of the objective function is set to 0, and a number of zero points are obtained; adjacent zero points among the number of zero points are combined into time periods, and a number of time periods are obtained; Determine whether the function value of the objective function in each time period is greater than 0; if yes, mark the corresponding time period as a key supply gap, otherwise mark it as a key demand gap.

7. The virtual private network-based quantum key encryption communication method according to claim 6, characterized in that: The quantum key is stored in a secure storage medium in advance by pre-filling, including: Taking the time period corresponding to the key supply gap as the integration region, integrating the objective function to obtain the key gap amount; The remaining keys of the key demand gap before the key supply gap are pre-filled into a secure storage medium to fill the key supply gap; wherein the number of remaining keys is greater than or equal to the key gap amount.

8. The virtual private network-based quantum key encryption communication method according to claim 7, characterized in that: Pre-filling the remaining key into the secure storage medium, comprising: Constructing secondary functions based on the objective function Among them, i is the number of the key demand gap. The smaller i is, the later the corresponding time range is. The time period corresponding to the key demand gap is [Ti d , Ti u ]; Mark the key gap amount as MQL and solve the formula The time range corresponding to the remaining keys is obtained, and the remaining keys within the time range are injected into the secure storage medium.

9. The virtual private network-based quantum key encryption communication method according to claim 1, characterized in that: When data is transmitted through the virtual private network, the encryption gateway performs encrypted transmission using a quantum key generated online or a quantum key pre-filled in the secure storage medium.

10. A quantum key encryption communication system based on a virtual private network, used to run the quantum key encryption communication method based on a virtual private network according to any one of claims 1 to 9, characterized in that: include: A virtual private network, and encryption gateways at both ends of the virtual private network; The encryption gateway encrypts the data to be transmitted by using a quantum key; The encryption gateway is connected to a secure storage medium, and the secure storage medium is used to store the pre-filled quantum key.

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