A smart meter privacy protection system and method

Abstract

The application discloses a kind of intelligent electric meter privacy protection system and method, it is related to privacy protection field, the system includes: terminal equipment group, concentrator and cloud server, terminal equipment group is responsible for the acquisition of electric data;Concentrator is as intermediate data processing device, is responsible for collecting the electric data that intelligent electric meter terminal equipment in jurisdiction is collected, and data is filtered, then encrypted transmission is carried out to cloud server with screening data;Cloud server carries out aggregate calculation and decryption to the encrypted screening data received, the authenticity of the intelligent electric meter terminal equipment is confirmed by two identity authentication requests in the system, the electric data collected by concentrator is filtered, improve the availability and authenticity of data, the encrypted screening data is encrypted by concentrator, and transmitted to cloud server, to ensure the confidentiality and security in data transmission process.The application can improve the protection effect of data privacy while ensuring the availability of data.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of privacy protection, and in particular to a smart meter privacy protection system and method. BACKGROUND

[0002] As an important two-way communication terminal device between smart grid and users, the smart meter has functions of power metering, meter reading and billing, two-way high-speed data communication and data terminal control, thereby providing more high-quality and diversified services for enterprises and customers. However, the smart meter collects fine-grained power consumption data, which is highly sensitive. Once the data is stolen or tampered with by attackers during the collection, transmission and aggregation analysis process, it will cause serious privacy leakage problems. For example, attackers can analyze the fine-grained power consumption data collected by the smart meter through data mining, and to some extent, obtain information such as user's life pattern, personal preferences and economic status, which seriously discloses personal privacy.

[0003] Generally, the way to protect data privacy is to anonymize the private data, blur the expression of the real meaning of the data, thereby reducing the risk of privacy leakage, but the attacker can still infer the user's private information according to the association between the background knowledge.

[0004] In addition, the differential privacy technology with strict theoretical proof is also often used to protect data privacy. By adding noise to the query results of published data, the attacker cannot infer the user's sensitive data information according to the change of the output results. For example, Qiang Wei Zhong et al. proposed a privacy protection method for smart meter data publishing based on differential privacy technology. The method first collects data and pre-processes to obtain a data set, and performs a plurality of query operations on the data set according to the task requirements; then calculates and analyzes the results of the plurality of query operations according to the predetermined mode, and records the results of the calculation and analysis as the original results; then adds noise to the results of the plurality of query operations based on the differential privacy technology, and performs calculation and analysis again based on the data, and records the results of this calculation and analysis as the interference results; then compares the error δ between the original results and the interference results and the preset threshold Th δ , if δ>Th δ , then add noise to the results of the plurality of query operations again to obtain new interference results by using the differential privacy technology, until δ<Th δ , and the latest interference results are published as the final query results, thereby realizing the protection of the privacy of the smart meter data. The scheme needs to perform multiple query and noise adding operations until δ<Th δThe time period can be ended, so that the required computing power of the scheme is greatly increased; meanwhile, the differential privacy technology needs to add noise to the query result, which reduces the availability of the data and is not conducive to the subsequent calculation and analysis of the data. It can be seen that the differential privacy technology has a good effect on the protection of data privacy, but it is difficult to balance the contradiction between the privacy and the availability of the data.

[0005] In addition, Liang Xiaobing et al. proposed a data aggregation scheme for smart meters in view of the privacy leakage problem that may be caused in the data aggregation process of smart meters. The scheme mainly includes four parts: smart meters, aggregation terminals, control centers and trusted third parties. The trusted third party is responsible for the initialization of the related parameters in the scheme. Then, the smart meters, aggregation terminals and control centers are registered with the trusted third party, the smart meters are registered with the aggregation terminals, and the aggregation terminals are registered with the control centers. Then, the smart meters send the user ID and other data information to the aggregation terminals, and the aggregation terminals obtain the user ID and then forward it to the trusted third party and the control center. Finally, the trusted third party sends the blinding factor generated based on the user ID to the aggregation terminal for data aggregation, so as to achieve the purpose of privacy protection in the data aggregation process. However, the scheme needs the participation of the trusted third party, but in actual application, the third party is not completely trusted, which greatly limits the effect of data privacy protection, and the effect of data privacy protection still needs to be improved. Meanwhile, the scheme involves encryption, decryption and signature verification of data in the data transmission process, so the complexity and cost of the scheme are high.

[0006] In summary, how to improve the protection effect of data privacy while ensuring the availability of data is still a problem to be solved at present. SUMMARY

[0007] Therefore, the embodiments of the present application provide a smart meter privacy protection system and method, which can balance the privacy and availability of data without the participation of a trusted third party, and can improve the protection effect of data privacy while ensuring the availability of data.

[0008] To achieve the above object, the embodiments of the present application provide the following scheme:

[0009] A smart meter privacy protection system, comprising: a terminal device group, a concentrator and a cloud server; the terminal device group and the cloud server are connected with the concentrator; the terminal device group is connected with the cloud server; the terminal device group comprises at least one smart meter terminal device;

[0010] Any of the smart meter terminal devices is configured to:

[0011] collect the power consumption data of a user;

[0012] sending a first identity authentication request to the concentrator; the first identity authentication request comprising: an IP address of the smart meter terminal device, a current time stamp of sending and a data volume of single transmission;

[0013] the concentrator is configured to:

[0014] determining whether the first identity authentication request meets a first set authentication condition; the first set authentication condition comprising: a first request time not exceeding a maximum time range of authentication request, the IP address of the smart meter terminal device being a pre-stored IP address of a real smart meter terminal device and the data volume of single transmission not exceeding a maximum data volume of single transmission; the first request time being an absolute value of a difference between a current time stamp received by the concentrator and the current time stamp of sending in the first identity authentication request;

[0015] if the first set authentication condition is met, the first-time authentication is successful, a response message is returned to the smart meter terminal device, and a same synchronization message as the first identity authentication request is sent to the cloud server; the response message comprising: a credential required for accessing the cloud server, an IP address of the cloud server, the data volume of single transmission and the time stamp of sending;

[0016] any of the smart meter terminal devices is further configured to:

[0017] sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message; the second identity authentication request comprising: the IP address of the smart meter terminal device, the credential required for accessing the cloud server and the current time stamp of sending;

[0018] the cloud server is configured to:

[0019] determining whether the synchronization message meets a second set authentication condition and whether the second identity authentication request meets a third set authentication condition; the second set authentication condition comprising: a second request time not exceeding the maximum time range of authentication request; the third set authentication condition comprising: a third request time not exceeding the maximum time range of authentication request; the second request time being an absolute value of a difference between a current time stamp received by the cloud server and the current time stamp of sending in the synchronization message; the third request time being an absolute value of a difference between the current time stamp received by the cloud server and the current time stamp of sending in the second identity authentication request;

[0020] If the synchronization message meets the second set authentication condition and the second identity authentication request meets the third set authentication condition, it is determined whether the smart meter terminal device IP address in the second identity authentication request is consistent with the smart meter terminal device IP address in the synchronization message, and if consistent, the second authentication is successful;

[0021] The concentrator is further configured to:

[0022] After the second authentication is successful, the power consumption data is filtered based on data density in a sliding window to obtain filtered data, the filtered data is encrypted, and the encrypted filtered data is transmitted to the cloud server by using a sliding window method.

[0023] The cloud server is further configured to:

[0024] The filtered data is aggregated and decrypted to obtain the filtered data.

[0025] Optionally, in the aspect of filtering the power consumption data based on data density in a sliding window to obtain filtered data by using a sliding window method, the concentrator is specifically configured to:

[0026] The power consumption data collected is iteratively filtered multiple times by using a sliding window method, with the data density in the current sliding window being unchanged compared with the data density in the last sliding window, to obtain the filtered data.

[0027] Optionally, in the aspect of iteratively filtering the power consumption data collected multiple times by using a sliding window method, with the data density in the current sliding window being unchanged compared with the data density in the last sliding window, to obtain the filtered data, the concentrator is specifically configured to:

[0028] The power consumption data collected is divided into multiple groups of data, and each group of data includes multiple data;

[0029] An initial center group is randomly selected, and a mean coordinate of the initial center group is calculated;

[0030] An initial sliding window is determined with the mean coordinate of the initial center group as the center and a randomly selected positive integer as the radius;

[0031] A data density of the initial sliding window is determined, and the data density is the number of groups of data in the sliding window;

[0032] A mean coordinate of each group of data in the initial sliding window is determined, and a mean coordinate of a new center group is determined according to the initial data density and the mean coordinate of each group of data in the initial sliding window;

[0033] moving the sliding window to the new center group, determining a new sliding window with the mean coordinate of the new center group as the center and a randomly selected positive integer as the radius;

[0034] determining the data density of the new sliding window, if the data density in the new sliding window is unchanged compared with the data density in the initial sliding window, stopping iteration and determining the data group in the sliding window of each iteration as the screening data, otherwise, performing next iteration.

[0035] Optionally, the concentrator, in aspects of encrypting the screening data and transmitting the encrypted screening data to the cloud server, is specifically used for:

[0036] generating a public key and a private key;

[0037] encrypting the screening data by using the public key to obtain encrypted screening data;

[0038] transmitting the private key and the encrypted screening data to the cloud server.

[0039] Optionally, the concentrator, in aspects of returning a response message to the smart meter terminal device and sending a synchronous message same as the first identity authentication request to the cloud server, is specifically used for:

[0040] encrypting the response message by using the key corresponding to the smart meter terminal device, and returning the encrypted response message to the smart meter terminal device;

[0041] encrypting the synchronous message by using the key of the cloud server, and sending the encrypted synchronous message to the cloud server.

[0042] Optionally, any of the smart meter terminal devices, in aspects of sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message, is specifically used for:

[0043] decrypting the encrypted response message by using the own key to obtain decrypted response message, and sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the decrypted response message.

[0044] Optionally, the cloud server, in aspects of judging whether the synchronous message meets a second set authentication condition, is specifically used for:

[0045] decrypting the encrypted synchronous message by using the own key to obtain decrypted synchronous message;

[0046] judging whether the decrypted synchronous message meets a second set authentication condition.

[0047] Optionally, the concentrator further comprises a database.

[0048] The database is used for storing initialization parameter information; the initialization parameter information comprises maximum data volume of single transmission of the smart meter terminal device, maximum time range of each authentication request, IP address of the smart meter terminal device, key corresponding to each smart meter terminal device and key of the cloud server.

[0049] The application further provides a smart meter privacy protection method, comprising:

[0050] The terminal device group collects user's power consumption data and sends a first identity authentication request to the concentrator; the first identity authentication request comprises IP address of the smart meter terminal device, current time stamp of sending and data volume of single transmission; the terminal device group comprises at least one smart meter terminal device.

[0051] The concentrator judges whether the first identity authentication request meets first set authentication conditions; the first set authentication conditions comprise that first request time does not exceed maximum time range of authentication request, IP address of the smart meter terminal device is IP address of the pre-stored real smart meter terminal device and data volume of single transmission does not exceed maximum data volume of single transmission; the first request time is absolute value of difference between current time stamp received by the concentrator and current time stamp of sending in the first identity authentication request.

[0052] If the first set authentication conditions are met, first authentication is successful, a response message is returned to the smart meter terminal device and a synchronous message same as the first identity authentication request is sent to the cloud server; the response message comprises credential required for accessing the cloud server, IP address of the cloud server, data volume of single transmission and time stamp of sending.

[0053] The smart meter terminal device sends a second identity authentication request to the cloud server according to IP address of the cloud server in the response message; the second identity authentication request comprises IP address of the smart meter terminal device, credential required for accessing the cloud server and current time stamp of sending.

[0054] The cloud server judges whether the synchronization message satisfies a second set authentication condition and whether the second identity authentication request satisfies a third set authentication condition; the second set authentication condition comprises that a second request time does not exceed a maximum time range of the authentication request; the third set authentication condition comprises that a third request time does not exceed the maximum time range of the authentication request; the second request time is an absolute value of a difference between a current time stamp received by the cloud server and a sent current time stamp in the synchronization message; and the third request time is an absolute value of a difference between the current time stamp received by the cloud server and a sent current time stamp in the second identity authentication request.

[0055] If the synchronization message satisfies the second set authentication condition and the second identity authentication request satisfies the third set authentication condition, it is judged whether an intelligent electric meter terminal device IP address in the second identity authentication request is consistent with an intelligent electric meter terminal device IP address in the synchronization message; if the two are consistent, the second authentication is successful.

[0056] After the second authentication is successful, the concentrator adopts a sliding window method to filter the power consumption data based on data density in the sliding window, obtains filtered data, encrypts the filtered data, and transmits the encrypted filtered data to the cloud server.

[0057] The cloud server aggregates and decrypts the encrypted filtered data to obtain the filtered data.

[0058] Optionally, the sliding window method is adopted to filter the power consumption data based on data density in the sliding window to obtain filtered data, and the filtering specifically comprises:

[0059] The sliding window method is adopted to perform multiple iterative filtering on the collected power consumption data with the data density in a current sliding window being unchanged compared with the data density in a previous sliding window as a target to obtain filtered data.

[0060] According to the embodiments of the present application, the following technical effects are provided:

[0061] The embodiment of the present application proposes a smart meter privacy protection system and method, which comprehensively protects the personal privacy information of users in the whole process of data collection, transmission and aggregation analysis from two aspects of identity authentication and data privacy protection of the smart meter terminal device. Firstly, the authenticity of the smart meter terminal identity is confirmed through twice identity authentication requests to prevent the access of false devices. Secondly, the sliding window method is adopted to filter the power consumption data collected by the smart meter terminal based on the data density in the sliding window, and the abnormal data is removed to improve the availability and authenticity of the data, and the filtered data is encrypted. Finally, the encrypted filtered data is transmitted to the cloud server for subsequent aggregation calculation and decryption to prevent data theft and improve data confidentiality. The present application can balance the privacy and availability of data without the participation of a trusted third party, and can improve the protection effect of data privacy while ensuring the availability of data. BRIEF DESCRIPTION OF DRAWINGS

[0062] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0063] Figure 1 The structural diagram of the smart meter privacy protection system provided by the embodiment of the present application is shown in the figure.

[0064] Figure 2 The specific implementation process diagram of the smart meter privacy protection system provided by the embodiment of the present application is shown in the figure.

[0065] Figure 3 The identity authentication mechanism schematic diagram provided by the embodiment of the present application is shown in the figure.

[0066] Figure 4 The data preprocessing flowchart provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0068] With the transformation and upgrading of smart grid, a large amount of power consumption data is generated in each link of the power system operation, and the data is analyzed and calculated by using data mining and cloud computing, which brings efficient and high-quality services to enterprises and customers. However, there is a serious risk of privacy leakage in the process of smart meter data collection, transmission and aggregation analysis, and the data is easily stolen by illegal persons, and then the data is frequently mined to obtain the sensitive personal privacy information of the user.

[0069] In view of the problem that the prior art needs a trusted third party to participate and the noise added to the data has a large impact on the availability of the data, the present application provides a smart meter privacy protection method and system, which comprehensively protects the personal privacy information of the user in the process of data collection, transmission and aggregation analysis from two aspects of terminal device identity authentication and data privacy protection, so as to realize the purpose of improving the protection effect of data privacy while ensuring the availability of data.

[0070] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0071] Embodiment one

[0072] Referring to Figure 1 The smart meter privacy protection system of the present embodiment comprises a terminal device group, a concentrator and a cloud server; the terminal device group and the cloud server are connected with the concentrator; the terminal device group is connected with the cloud server; the terminal device group comprises at least one smart meter terminal device.

[0073] Any of the smart meter terminal devices is used for collecting power consumption data of a user, sending a first identity authentication request to the concentrator, and the first identity authentication request comprises a smart meter terminal device IP address, a current time stamp of sending and a data volume of single transmission.

[0074] The concentrator is used for judging whether the first identity authentication request meets a first set authentication condition; the first set authentication condition comprises that a first request time does not exceed a maximum time range of authentication request, the smart meter terminal device IP address is a pre-stored IP address of a real smart meter terminal device and the data volume of single transmission does not exceed a maximum data volume of single transmission; the first request time is an absolute value of a difference between a current time stamp received by the concentrator and the current time stamp of sending in the first identity authentication request.

[0075] If the first set authentication condition is met, the first authentication is successful, and a response message is returned to the smart meter terminal device, and a same synchronization message as the first identity authentication request is sent to the cloud server; the response message includes: a credential required for accessing the cloud server, an IP address of the cloud server, a data volume of a single transmission, and a timestamp of transmission.

[0076] Any of the smart meter terminal devices further configured to: send a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message; the second identity authentication request includes: an IP address of the smart meter terminal device, a credential required for accessing the cloud server, and a current timestamp of transmission.

[0077] The cloud server is configured to: determine whether the synchronization message meets a second set authentication condition, and whether the second identity authentication request meets a third set authentication condition; the second set authentication condition includes: a second request time does not exceed a maximum time range of authentication request; the third set authentication condition includes: a third request time does not exceed the maximum time range of authentication request; the second request time is an absolute value of a difference between a current timestamp received by the cloud server and a current timestamp of transmission in the synchronization message; the third request time is an absolute value of a difference between the current timestamp received by the cloud server and a current timestamp of transmission in the second identity authentication request.

[0078] If the synchronization message meets the second set authentication condition and the second identity authentication request meets the third set authentication condition, it is determined whether the IP address of the smart meter terminal device in the second identity authentication request is consistent with the IP address of the smart meter terminal device in the synchronization message, and if so, the second authentication is successful.

[0079] The concentrator is further configured to: after the second authentication is successful, filter the power consumption data based on a data density in a sliding window by using a sliding window method, obtain filtered data, encrypt the filtered data, and transmit the encrypted filtered data to the cloud server.

[0080] The cloud server is further configured to: aggregate and decrypt the encrypted filtered data to obtain the filtered data.

[0081] In one example, the concentrator, in the aspect of filtering the power consumption data based on a data density in a sliding window by using a sliding window method, is specifically configured to:

[0082] The method of the sliding window is adopted, and the data density in the current sliding window is compared with the data density in the last sliding window, and the data density is not changed as the target, and the collected power consumption data is iterated and screened multiple times to obtain screened data. The specific screening process is:

[0083] The collected power consumption data is divided into multiple data groups, and each data group includes multiple data; a group is randomly selected as an initial center group, and the mean coordinates of the initial center group are calculated; the mean coordinates of the initial center group are taken as the center, and a random positive integer is taken as the radius to determine an initial sliding window; the data density of the initial sliding window is determined; the data density is the number of data groups in the sliding window; the mean coordinates of each data group in the initial sliding window are determined, and the mean coordinates of a new center group are determined according to the initial data density and the mean coordinates of each data group in the initial sliding window; the sliding window is moved to the new center group, the mean coordinates of the new center group are taken as the center, and a random positive integer is taken as the radius to determine a new sliding window; the data density of the new sliding window is determined, if the data density in the new sliding window is unchanged compared with the data density in the initial sliding window, the iteration is stopped, and the data groups in the sliding window of each iteration are determined as screened data, otherwise, the next iteration is performed.

[0084] In one example, the concentrator, in the aspect of encrypting the screened data and transmitting the encrypted screened data to the cloud server, is specifically used for: generating a public key and a private key; encrypting the screened data by using the public key to obtain encrypted screened data; and transmitting the private key and the encrypted screened data to the cloud server.

[0085] The specific process of generating the public key and the private key is: a) generating a public key. Randomly selecting three integers a, b and g, and taking n=ab, the public key k pub is (n, g). b) generating a private key. Taking λ=lcm(a-1, b-1), and defining a function x as an independent variable, calculating μ=(L(g λ mod n 2 )) -1 mod n, the private key k pri is (λ, μ).

[0086] In the above two steps a) and b), a and b need to satisfy gcd((a-1)(b-1), n)=1, wherein lcm() returns the least common multiple, gcd() returns the greatest common divisor, and mod represents the modulo operation.

[0087] The specific process of encrypting and transmitting the screened data is:

[0088] A random integer r is selected, satisfying 0 < r < n, and c = g m r n mod n 2 The data is encrypted, where m is the plaintext data (i.e., the screening data), c is the encrypted ciphertext data (i.e., the encrypted screening data) using k pub .

[0089] After the data encryption is completed, the concentrator sends the data to the cloud server in the form of a binary tuple (k pri , c), where k pri represents the private key generated by the concentrator, which is used by the cloud server to subsequently decrypt the ciphertext result.

[0090] In one example, the cloud server, in terms of aggregating and decrypting the encrypted screening data, obtains the screening data, and is specifically used for:

[0091] After the encrypted transmission is completed, the cloud server performs aggregating calculation on the encrypted screening data according to specific needs, and specifically uses homomorphic encryption technology to perform calculation, and the calculation principle is as follows:

[0092] Dec(c⊙c) = Dec(c)⊙Dec(c), that is, calculating first and then decrypting is equivalent to decrypting first and then calculating, where Dec() is a decryption function, and represents a specific operation, for example, multiplication or addition. The operation form is selected according to actual needs, and is not limited here.

[0093] After the calculation is completed, the aggregated and calculated ciphertext data is decrypted, and the decryption steps are as follows:

[0094] According to m = L(c1 λ mod n 2 )*μmod n, the aggregated and calculated ciphertext data is decrypted, where c1 is the aggregated and calculated ciphertext data, m is the plaintext data obtained after decryption, and mod represents a remainder operation.

[0095] In one example, the concentrator, in terms of returning a response message to the smart meter terminal device and sending a synchronization message identical to the first identity authentication request to the cloud server, is specifically used for: encrypting the response message using the key corresponding to the smart meter terminal device, and returning the encrypted response message to the smart meter terminal device; and encrypting the synchronization message using the key of the cloud server, and sending the encrypted synchronization message to the cloud server.

[0096] Any of the smart meter terminal devices, in terms of sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message, is specifically used for: decrypting the encrypted response message by using the own key to obtain the decrypted response message, and sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the decrypted response message.

[0097] The cloud server, in terms of judging whether the synchronization message meets the second set authentication condition, is specifically used for: decrypting the encrypted synchronization message by using the own key to obtain the decrypted synchronization message; and judging whether the decrypted synchronization message meets the second set authentication condition.

[0098] In one example, the concentrator further comprises a database; the database is used for storing initialization parameter information; the initialization parameter information includes: maximum data volume of single transmission of the smart meter terminal device, maximum time range of each authentication request, IP address of the smart meter terminal device, key corresponding to each smart meter terminal device and key of the cloud server.

[0099] In actual application, a more specific implementation process of the smart meter privacy protection system of the above embodiment is as follows:

[0100] In view of the problem of privacy leakage possibly caused by the smart meter in the process of data collection, transmission and cloud aggregation analysis, a smart meter privacy protection scheme based on homomorphic encryption is proposed, which mainly involves three parts of a terminal device group, a concentrator and a cloud server, wherein the terminal device group refers to the smart meter installed on the user side, mainly responsible for collecting high-frequency household fine-grained power consumption data; the concentrator is an intermediate data processing device, mainly responsible for collecting the data collected by the smart meter terminal in the jurisdiction, and pre-processing the data, and then transmitting the encrypted data to the cloud server; the cloud server is mainly responsible for initializing the related parameter information and aggregating and calculating the received encrypted data to understand the user power consumption in the jurisdiction and timely adjust the strategy to provide better service for enterprises and customers.

[0101] Firstly, the terminal device identity authentication mechanism proposed by the embodiment of the application confirms the authenticity of the terminal device through two communication authentication requests to prevent the access of false terminal devices; secondly, the concentrator pre-processes the collected data to remove abnormal data and improve the availability and authenticity of the data; finally, the concentrator encrypts the pre-processed data by using an encryption algorithm and transmits the data to the cloud server to ensure the confidentiality and security in the data transmission process. The flow of the privacy protection method is as shown in Figure 2

[0102] (1) Terminal device identity authentication mechanism.​

[0103] In order to prevent false devices from tampering and destroying data, the present application proposes a terminal device identity authentication mechanism, and the identity authentication mechanism process is as shown in the figure. Figure 3

[0104] a) initialization parameter information. The cloud server initializes the parameter information, and sends the initialization information to the built-in database of the concentrator for storage, which is used for subsequent identity authentication. The content of the initialization information is represented by a five-tuple as I=(D max ,T max ,E ip ,K ip ,K server ), wherein D max represents the maximum data amount of single transmission of the smart meter terminal, T max represents the maximum time range of each authentication request, E ip represents the IP address of the smart meter terminal device, K ip represents the key corresponding to the smart meter terminal device, each terminal device has its own key, and K server represents the key of the cloud server.

[0105] b) authentication request. The terminal device sends a first identity authentication request M1 to the concentrator, and M1 is represented by a three-tuple as (E ip ,T,D), wherein E ip represents the IP address of the smart meter terminal device, T represents the current timestamp, and D represents the data amount of single transmission.

[0106] c) parameter information judgment.

[0107] ⅰ. After the concentrator receives the information M1, the current timestamp is recorded as T now , the size of |T now -T| and T max is compared, and it is judged whether the information M1 is invalid due to exceeding the maximum time range of the authentication request. If |T now -T|>T max , the maximum time range of single request authentication is exceeded, the message M1 is invalid, and the authentication fails; if |T now -T|<T max , it indicates that the time range of single request authentication is not exceeded, the message M1 is valid, and the next step is continued.

[0108] ⅱ. According to E ip in M1, it is judged whether the smart meter exists in the built-in data of the concentrator, and whether the identity of E ip is real. Whether the smart meter exists is to see whether E ip ​If it is not found, the device is considered to be a fake device and the authentication fails; if it is found ip , it means the terminal device identity is authentic, proceed to the next step.

[0109] ⅲ. According to D in M1, D is stored in the database built into the concentrator. max Compare and determine whether the maximum amount of data transmitted in a single time is exceeded. max , it means that the amount of single data that the terminal device wants to transmit exceeds the limit, and the authentication is terminated; if D<D max , it means that the amount of data transmitted by the terminal device in a single time is legal, and proceed to the next step.

[0110] d) Authentication feedback. If |T now -T|<T max , that is, M1 is effective; D<D max , that is, the maximum amount of data for a single transmission is not exceeded; and the E ip , that is, the identity of this terminal device is real (that is, when the timestamp is legal, the identity of the terminal device is real and the amount of data is legal), the concentrator sends a ip Return a response message R1 and use the K of the current terminal device ip Encryption, the R1 = (ricket, S ip ,D,T), where ticket represents the credentials required to access the cloud server, S ip It represents the IP address of the cloud server, D represents the amount of data transmitted in a single time, and T represents the timestamp.

[0111] e) Synchronous transmission of device information. The concentrator returns a response message R1 to the terminal device and sends a message S1 to the cloud server = (E ip ,T,D), and S1 uses the key K of the cloud server server encryption.

[0112] f) Obtain access credentials. After receiving the response message R1, the terminal device uses its own key to obtain the ticket and S ip Since only real terminal devices have the key, fake devices cannot have this key and cannot decrypt message R1.

[0113] g) Authentication request. The terminal device receives the authentication request according to S ip Send the second identity authentication request M2 to the cloud server = (E ip ,ticket,T).

[0114] h) Parameter information judgment.

[0115] i. The cloud server uses its own key to decrypt S1, compares the timestamp T in 11 with the current timestamp T now to determine whether the information S1 is invalid due to exceeding the maximum time range of the authentication request. If |T now -T| > T max , the maximum time range of a single request authentication is exceeded, the message S1 is invalid, and the authentication fails; if |T now -T| < T max , it means that the maximum time range of a single request authentication is not exceeded, the message S1 is valid, and the next step is continued.

[0116] ii. The cloud server compares the timestamp T in M2 with the current timestamp T now to determine whether the information M2 is invalid due to exceeding the maximum time range of the authentication request.

[0117] iii. Authentication message comparison. If S1 and M2 are both not invalid, compare the E ip obtained in S1 with the E ip obtained in M2. If they are consistent, the device identity authentication is successful; if they are not consistent, the device identity authentication fails.

[0118] (2) Data preprocessing.

[0119] After the terminal device identity verification, the concentrator pre-processes the data transmitted by the terminal devices in the jurisdiction to remove abnormal data, thereby improving the usability and authenticity of the data. Referring to Figure 4 , the data preprocessing steps and processes are as follows:

[0120] a) Data division: each data is represented as (x i , yi) in a two-dimensional coordinate system, where 1≤i≤n, and the data collected by the concentrator is divided into k groups, each group containing q data.

[0121] b) Determine the center group: randomly select one group as the initial center group G to facilitate the iteration of the subsequent algorithm and reduce the computational overhead. Calculate the mean coordinate of the initial center group. The coordinate calculation method of the initial center group G is

[0122] c) Generate a sliding window: randomly select a positive integer w, and take the mean coordinate of the initial center group as the center and w as the radius to generate a circle as the sliding window.

[0123] d) Obtain the window density p: the window density is the number of data groups in the current window.

[0124] e) Obtain the mean coordinate of each data group in the window: the mean coordinate of the data in the window is calculated as and the calculation result is taken as the new center group coordinate of the current window, wherein (x', y') represents the center group coordinate of each group. i i

[0125] f) window moving: the window is moved to the new center point coordinate, and the above steps are repeated iteratively until the density p in the window no longer changes compared with the last time, and then the iteration is ended.

[0126] g) data processing: the data contained in the multiple sliding windows generated by multiple iterations is retained, and the remaining data is discarded as abnormal data.

[0127] (3) key generation.

[0128] After the data preprocessing is completed, in order to prevent the data from being intercepted in the transmission process from the concentrator to the cloud server, a pair of keys k pub -k pri are generated locally in the concentrator for data encryption, and the specific generation steps of the public key and the private key in the key pair are not repeated here.

[0129] (4) data encryption and transmission. The specific process of this step is not repeated here.

[0130] (5) data calculation and analysis. In order to ensure that the source data is not exposed in the process of cloud server aggregation analysis, the ciphertext data is directly calculated based on the homomorphic encryption technology principle here. The calculation and analysis process is not repeated here.

[0131] (6) data decryption. After the calculation is completed, the ciphertext result is decrypted to improve the security and confidentiality of the data. The decryption process is not repeated here.

[0132] The embodiment of the application proposes a smart meter privacy protection system based on homomorphic encryption from the aspects of terminal device identity authentication and data privacy protection. The application confirms the authenticity of the smart meter identity through two identity authentications of the device terminal, which can prevent the damage to the data caused by the false device access. At the same time, the device itself key is used in the two communication authentication request processes, and the false device cannot obtain the key and cannot decrypt the information in the communication process. Then, the data set is grouped, a sliding window is set for data preprocessing, which can effectively reduce the iteration number of the algorithm and improve the real-time performance of data transmission. At the same time, the algorithm based on density is less affected by the mean than other algorithms. In addition, the preprocessed data is encrypted and transmitted, and then specific calculation and analysis are performed on the data without exposing the original data, which can greatly improve the security and confidentiality of the data.

[0133] ​​In addition, for the proposed system of the present embodiment, there are still other alternatives to achieve the effect. For example, differential privacy is used to disturb data in the process of transmitting data to the cloud server to achieve the purpose of protecting data. However, the damage caused by this method to the data is irreversible, so it will cause the availability of the data to decrease.

[0134] Embodiment two

[0135] In order to realize the system corresponding to the above-mentioned embodiment one, to obtain the corresponding function and technical effect, the following provides an intelligent electric meter privacy protection method. The method comprises:

[0136] The terminal device group collects the user's power consumption data and sends a first identity authentication request to the concentrator; the first identity authentication request includes: intelligent electric meter terminal device IP address, current timestamp of sending and single transmission data volume; the terminal device group includes: at least one intelligent electric meter terminal device.

[0137] The concentrator judges whether the first identity authentication request meets the first set authentication condition; the first set authentication condition includes: the first request time does not exceed the maximum time range of authentication request, the intelligent electric meter terminal device IP address is the IP address of the pre-stored real intelligent electric meter terminal device and the single transmission data volume does not exceed the maximum data volume of single transmission; the first request time is the absolute value of the difference between the current timestamp received by the concentrator and the current timestamp of sending in the first identity authentication request.

[0138] If the first set authentication condition is met, the first authentication is successful, and a response message is returned to the intelligent electric meter terminal device, and a synchronous message same as the first identity authentication request is sent to the cloud server; the response message includes: the credential required for accessing the cloud server, the IP address of the cloud server, the single transmission data volume and the timestamp of sending.

[0139] The intelligent electric meter terminal device sends a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message; the second identity authentication request includes: intelligent electric meter terminal device IP address, credential required for accessing the cloud server and current timestamp of sending.

[0140] The cloud server judges whether the synchronization message meets a second set authentication condition and whether the second identity authentication request meets a third set authentication condition; the second set authentication condition includes that a second request time does not exceed a maximum time range of an authentication request; the third set authentication condition includes that a third request time does not exceed the maximum time range of the authentication request; the second request time is an absolute value of a difference between a current time stamp received by the cloud server and a sent current time stamp in the synchronization message; and the third request time is an absolute value of a difference between the current time stamp received by the cloud server and a sent current time stamp in the second identity authentication request.

[0141] If the synchronization message meets the second set authentication condition and the second identity authentication request meets the third set authentication condition, it is judged whether an intelligent electric meter terminal device IP address in the second identity authentication request is consistent with an intelligent electric meter terminal device IP address in the synchronization message; if yes, the second authentication is successful.

[0142] After the second authentication is successful, the concentrator adopts a sliding window method to filter the power consumption data based on data density in the sliding window, obtain filtered data, encrypt the filtered data, and transmit the encrypted filtered data to the cloud server.

[0143] The cloud server aggregates and decrypts the encrypted filtered data to obtain the filtered data.

[0144] In one example, the sliding window method is adopted to filter the power consumption data based on data density in the sliding window to obtain filtered data, and the filtering specifically includes:

[0145] The sliding window method is adopted to perform multiple iteration filtering on the collected power consumption data with the data density in a current sliding window being unchanged compared with the data density in a previous sliding window as a target to obtain filtered data.

[0146] The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the method disclosed in the embodiments, since it corresponds to the system disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the system part description.

[0147] The principles and implementation manners of the present application are described by using specific examples in the present application, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for the general technical personnel in the art, the specific implementation manners and application ranges will be changed according to the idea of the present application. In conclusion, the content of the present specification should not be understood as the limitation of the present application.

Claims

1. A smart meter privacy protection system, characterized in that: include: Terminal device clusters, concentrators, and cloud servers; The terminal device group and the cloud server are both connected to the concentrator; The terminal device group is connected to the cloud server; the terminal device group includes: at least one smart meter terminal device; Any of the above-mentioned smart meter terminal devices is used for: Collect users' electricity consumption data; Sending a first identity authentication request to the concentrator; the first identity authentication request includes: the IP address of the smart meter terminal device, the current timestamp of the transmission, and the amount of data transmitted in a single transmission; The concentrator is used to: Determining whether the first identity authentication request satisfies a first set authentication condition; the first set authentication condition includes: the first request time does not exceed the maximum time range of the authentication request, the smart meter terminal device IP address is a pre-stored real smart meter terminal device IP address, and the amount of data transmitted in a single transmission does not exceed the maximum amount of data transmitted in a single transmission; the first request time is the absolute value of the difference between the current timestamp received by the concentrator and the current timestamp sent in the first identity authentication request; If the first set authentication condition is met, the first authentication is successful, and a response message is returned to the smart meter terminal device, and a synchronization message identical to the first identity authentication request is sent to the cloud server; the response message includes: the credentials required to access the cloud server, the IP address of the cloud server, the amount of data transmitted in a single transmission, and the timestamp of the transmission; Any of the above-mentioned smart meter terminal devices is further used for: Sending a second identity authentication request to the cloud server based on the IP address of the cloud server in the response message; the second identity authentication request includes: the IP address of the smart meter terminal device, the credentials required to access the cloud server, and the current timestamp of the sending; The cloud server is used to: Determine whether the synchronization message satisfies a second set authentication condition and whether the second identity authentication request satisfies a third set authentication condition; the second set authentication condition includes: the second request time does not exceed the maximum time range of the authentication request; the third set authentication condition includes: the third request time does not exceed the maximum time range of the authentication request; the second request time is the absolute value of the difference between the current timestamp received by the cloud server and the current timestamp sent in the synchronization message; the third request time is the absolute value of the difference between the current timestamp received by the cloud server and the current timestamp sent in the second identity authentication request; If the synchronization message satisfies the second set authentication condition and the second identity authentication request satisfies the third set authentication condition, determining whether the smart meter terminal device IP address in the second identity authentication request is consistent with the smart meter terminal device IP address in the synchronization message. If they are consistent, the second authentication is successful. The concentrator is further configured to: When the second authentication is successful, the power consumption data is filtered based on the data density within the sliding window using a sliding window method to obtain filtered data, the filtered data is encrypted, and the encrypted filtered data is transmitted to the cloud server; The cloud server is also used for: Aggregate calculation and decryption are performed on the encrypted screening data to obtain the screening data.

2. The smart meter privacy protection system according to claim 1, characterized in that: The concentrator, in adopting a sliding window method, filters the power consumption data based on the data density within the sliding window to obtain filtered data, is specifically used to: The sliding window method is adopted, with the goal of keeping the data density in the current sliding window unchanged compared with the data density in the previous sliding window, and the collected electricity consumption data are iteratively screened multiple times to obtain screened data.

3. The smart meter privacy protection system according to claim 2, characterized in that: The concentrator uses a sliding window method, with the goal of ensuring that the data density in the current sliding window remains unchanged compared to the data density in the previous sliding window, to perform multiple iterative screenings on the collected power consumption data to obtain the screened data, specifically for: The collected electricity consumption data is divided into multiple data groups, each of which includes multiple data; Randomly select a group as an initial center group, and calculate the mean coordinates of the initial center group; Determine an initial sliding window with the mean coordinate of the initial central group as the center and a randomly selected positive integer as the radius; Determining the data density of the initial sliding window; the data density is the number of data groups within the sliding window; Determine the mean coordinates of each data group in the initial sliding window, and determine the mean coordinates of a new center group based on the data density of the initial sliding window and the mean coordinates of each data group in the initial sliding window; Move the sliding window to the new central group, and determine a new sliding window with the mean coordinate of the new central group as the center and a randomly selected positive integer as the radius; Determine the data density of the new sliding window. If the data density in the new sliding window is unchanged compared with the data density in the initial sliding window, stop the iteration and determine the data group in the sliding window of each iteration as the screening data. Otherwise, proceed to the next iteration.

4. The smart meter privacy protection system according to claim 1, characterized in that: The concentrator, in terms of encrypting the screening data and transmitting the encrypted screening data to the cloud server, is specifically configured to: Generate public and private keys; encrypting the screening data using the public key to obtain encrypted screening data; The private key and the encrypted screening data are transmitted to the cloud server.

5. The smart meter privacy protection system according to claim 1, characterized in that: The concentrator, in terms of returning a response message to the smart meter terminal device and sending a synchronization message identical to the first identity authentication request to the cloud server, is specifically configured to: Encrypting the response message using the key corresponding to the smart meter terminal device, and returning the encrypted response message to the smart meter terminal device; The synchronization message is encrypted using the key of the cloud server, and the encrypted synchronization message is sent to the cloud server.

6. The smart meter privacy protection system according to claim 5, characterized in that: Any of the smart meter terminal devices, in sending a second identity authentication request to the cloud server according to the IP address of the cloud server in the response message, is specifically configured to: The encrypted response message is decrypted using its own key to obtain a decrypted response message, and a second identity authentication request is sent to the cloud server based on the IP address of the cloud server in the decrypted response message.

7. The smart meter privacy protection system according to claim 5, characterized in that: The cloud server, in determining whether the synchronization message satisfies the second set authentication condition, is specifically configured to: Decrypt the encrypted synchronization message using its own key to obtain the decrypted synchronization message; It is determined whether the decrypted synchronization message meets a second set authentication condition.

8. The smart meter privacy protection system according to claim 1, characterized in that: The concentrator further includes: a database; The database is used to store initialization parameter information; the initialization parameter information includes: the maximum amount of data transmitted by the smart meter terminal device in a single transmission, the maximum time range of each authentication request, the IP address of the smart meter terminal device, the key corresponding to each smart meter terminal device and the key of the cloud server.

9. A smart meter privacy protection method, characterized in that: include: The terminal device group collects the user's electricity consumption data and sends the first identity authentication request to the concentrator; The first identity authentication request includes: the IP address of the smart meter terminal device, the current timestamp sent, and the amount of data transmitted in a single transaction; The terminal device group includes: at least one smart meter terminal device; the concentrator determines whether the first identity authentication request meets a first set authentication condition; the first set authentication condition includes: the first request time does not exceed the maximum time range of the authentication request; the IP address of the smart meter terminal device is a pre-stored IP address of a real smart meter terminal device; and the amount of data transmitted in a single transmission does not exceed the maximum amount of data transmitted in a single transmission; the first request time is the absolute value of the difference between a current timestamp received by the concentrator and a current timestamp sent in the first identity authentication request; If the first set authentication condition is met, the first authentication is successful, and a response message is returned to the smart meter terminal device, and a synchronization message identical to the first identity authentication request is sent to the cloud server; the response message includes: the credentials required to access the cloud server, the IP address of the cloud server, the amount of data transmitted in a single transmission, and the timestamp of the transmission; The smart meter terminal device sends a second identity authentication request to the cloud server based on the IP address of the cloud server in the response message; the second identity authentication request includes: the IP address of the smart meter terminal device, the credentials required to access the cloud server, and the current timestamp of the sending; The cloud server determines whether the synchronization message satisfies a second set authentication condition and whether the second identity authentication request satisfies a third set authentication condition; the second set authentication condition includes: the second request time does not exceed the maximum time range of the authentication request; the third set authentication condition includes: the third request time does not exceed the maximum time range of the authentication request; the second request time is the absolute value of the difference between the current timestamp received by the cloud server and the current timestamp sent in the synchronization message; the third request time is the absolute value of the difference between the current timestamp received by the cloud server and the current timestamp sent in the second identity authentication request; If the synchronization message satisfies the second set authentication condition and the second identity authentication request satisfies the third set authentication condition, determining whether the smart meter terminal device IP address in the second identity authentication request is consistent with the smart meter terminal device IP address in the synchronization message. If they are consistent, the second authentication is successful. When the second authentication is successful, the concentrator uses a sliding window method to filter the power consumption data based on the data density within the sliding window to obtain filtered data, encrypts the filtered data, and transmits the encrypted filtered data to the cloud server; The cloud server performs aggregate calculation and decryption on the encrypted screening data to obtain the screening data.

10. A smart meter privacy protection method according to claim 9, characterized in that: The sliding window method is used to filter the electricity consumption data based on the data density within the sliding window to obtain filtered data, specifically including: The sliding window method is adopted, with the goal of keeping the data density in the current sliding window unchanged compared with the data density in the previous sliding window, and the collected electricity consumption data are iteratively screened multiple times to obtain screened data.

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