A method and system for protecting user location information

Abstract

The present invention provides a method and system for protecting user location information, including: when a user obtains authentication information, receiving a first query request sent by the user; in response to the first query request, determining an anonymous area using a regional adaptive anonymity algorithm, and sending an encrypted query request generated according to the anonymous area to a location service provider; receiving encrypted location point of interest information obtained by the location service provider based on authentication by a certificate issuing authority, and forwarding the encrypted location point of interest information to the user, so that the user can obtain target location information from the encrypted location point of interest information. The present invention improves security when resisting inference attacks by decoupling user personal data and location data, reduces communication overhead and computing overhead of user terminals, and effectively achieves a balance between user location privacy and service quality.

Description

Technical Field

[0001] The present invention relates to the field of network security technology, and in particular to a method and system for protecting user location information. Background Art

[0002] Mobile Social Networks (MSNs) are complex networks that have the characteristics of both traditional online social networks (OSNs) and location-based social networks (LBSNs). With the rapid development of mobile social networks, location-based services (LBS) have also gained greater development, greatly facilitating the lives of users. While users enjoy the many conveniences brought by these applications, their privacy protection is also subject to major security threats. In order to obtain higher quality services, mobile users need to provide accurate location information to location service providers (LSPs). As shown in Table 1, the characteristics of LBS services in mobile social networks can be abstracted as follows: 1) Users need to authenticate their identities to obtain services; 2) Users need to provide personal information to obtain services; 3) Single-point LBS services are the main focus.

[0003] Table 1

[0004]

[0005]

[0006] Since there are potential attackers in location service providers, LBS applications provide convenient services to users, but are also vulnerable to malicious attacks by attackers, and the user's location privacy is at risk of being leaked. The user's location information and query information can be easily obtained by LBS servers or other entities. If these servers are attacked by malicious attackers, the user's personal privacy information will be leaked. Therefore, the location privacy security of users in mobile social networks is an issue that needs to be urgently addressed.

[0007] There are three common ways of location information leakage: 1) Location servers leak users' location privacy. When users seek location services from location service providers, they must first send their own locations and needs to the location server, and then the location server provides corresponding services to users. At this time, the location server contains information such as the user's location and shared content. Once an attacker obtains the user's location information by attacking the server, it will cause immeasurable losses; 2) Users actively share their location and leak their location privacy. Users can directly share their location information on social media such as Moments, QQ Space or Weibo, which may lead to the leakage of users' location privacy. Attackers can indirectly use certain location service applications to infer users' real locations and movement trajectories. For example, WeChat Sports or other applications that support searching for nearby friends may be maliciously used by attackers to infer users' real locations; 3) Location trajectory data leaks user privacy. Attackers obtain personal sensitive information such as personal hobbies, behavioral habits, lifestyle, etc. by mining and analyzing historical trajectory data. They may also combine information such as payment records or social networks to infer user identities. The goal of location privacy protection is to prevent others from obtaining the user's past or present location or trajectory information without the user's knowledge. The specific goals can be expressed as: 1) increase the uncertainty of the user's identity, hide the user's identity or encrypt the user's identity so that the attacker cannot determine the user's identity; 2) increase the uncertainty of the location, hide the location information or encrypt the location information so that the attacker cannot determine the user's specific location; 3) eliminate the association between the user's identity and location so that the attacker cannot associate the user with the location he visits. There are two privacy concepts in mobile social networks: weak location privacy and strong location privacy. The former means that the attacker can infer that the user is in a privacy area, but cannot determine its exact location. The solution is generally based on location perturbation, spatial anonymity and spatial transformation; the latter means that the attacker cannot infer the user's specific location at all. The solution is often combined with encryption technology. In order to deal with the threats faced by users' location privacy, the common location privacy protection mechanisms currently available are mainly divided into the following three categories: (1) k-anonymity-based schemes; (2) obfuscation-based schemes; (3) differential privacy-based schemes.

[0008] The above scheme has the following problems: (1) The introduction of a trusted third-party anonymous server: Typical location privacy protection algorithms are mostly based on a centralized architecture, including a single trusted third party (STTP), that is, an anonymous server. Although the introduction of a trusted third-party anonymous server has greatly facilitated the realization of location privacy protection to some extent, its existence also poses the following threats. 1) STTP records the accurate location information of all users, making it an attractive target for attackers. Once an attacker successfully breaks into the STTP server, the attacker will be able to access all user information processed by the server; 2) All queries submitted by the user end must pass through the STTP server, which not only increases the communication overhead, but also makes the server a central failure point, forming a performance bottleneck; 3) In reality, it is difficult to find a completely trustworthy entity. (2) The balance between user location privacy and service quality: For existing location privacy protection methods based on k-anonymity, obfuscation and other technologies, the most important problem is how to control the service quality. Some existing solutions are too costly and difficult to achieve satisfactory results. For example, solutions based on spatial anonymity technology sometimes need to sacrifice a certain LBS applicability, which makes such solutions difficult to apply in personal location service applications. For LBS service providers, in order to provide higher service quality, when they come into contact with the indirect location information of users, how to obtain information closer to the user's real location based on the indirect information is a key research issue. At the same time, it is necessary to comprehensively consider the limitations of the computing power and storage capacity of the user side to ensure the best user experience.

[0009] In summary, existing technical solutions have problems such as high communication overhead, high computing overhead of user devices, high correlation between user personal data and location data information, and imbalance between user location privacy and service quality. Summary of the invention

[0010] The present invention provides a user location information protection method and system to solve the defects in the prior art of high communication overhead, high calculation overhead of user equipment, high correlation between user personal data and location data information, and imbalance between user location privacy and service quality.

[0011] In a first aspect, the present invention provides a method for protecting user location information, comprising:

[0012] After the user obtains authentication information, a first query request sent by the user is received;

[0013] In response to the first query request, determine an anonymous area using a region-adaptive anonymity algorithm, and send an encrypted query request generated according to the anonymous area to a location service provider;

[0014] The encrypted location POI information obtained by the location service provider through authentication by a certificate issuing authority is received, and the encrypted location POI information is forwarded to the user, so that the user can obtain target location information according to the encrypted location POI information.

[0015] According to a user location information protection method provided by the present invention, the user to be a user obtains authentication information and receives a first query request sent by the user, including:

[0016] The user sends a location request to the location service provider and registers with the certificate issuing authority, and the user receives a pseudonym, certificate and key including a certificate period issued by the certificate issuing authority;

[0017] The first query request sent by the user based on the location mapping table is received.

[0018] According to a user location information protection method provided by the present invention, the receiving the first query request sent by the user based on the location mapping table includes:

[0019] Obtaining any user location coordinate value, calculating a hash value of the any user location coordinate value, and performing a modulo operation on the number of anonymous servers to obtain any anonymous server serial number;

[0020] Constructing the location mapping table based on any anonymous server serial number and any user location coordinate value;

[0021] The user determines a receiving anonymous server according to the location mapping table, and the receiving anonymous server receives the pseudonym, the certificate, the certificate period, query request content, query radius and anonymity level sent by the user.

[0022] According to a user location information protection method provided by the present invention, in response to the first query demand, an anonymous area is determined by using a regional adaptive anonymity algorithm, and an encrypted query request generated according to the anonymous area is sent to a location service provider, including:

[0023] receiving the first query requirement, and if it is determined that the same pseudonym as the user exists within the certificate period, sending a first mark to the user, and generating the anonymous region based on the region adaptive anonymity algorithm;

[0024] Otherwise, cache the first query demand, send a second tag to the user, receive a second query demand sent by the user, wherein the second query demand includes the second tag and the user query location, and cache after associating the user query location, the pseudonym, and the certificate expiration date;

[0025] The pseudonym, the certificate, the certificate period, the query request content, the query radius and the anonymous area are combined to obtain a comprehensive query request, and the comprehensive query request is encrypted using the public key of the location service provider to obtain an encrypted query request.

[0026] According to a user location information protection method provided by the present invention, the generating of the anonymous area based on the area adaptive anonymity algorithm comprises:

[0027] receiving the first query request sent by the user and carrying the user query location;

[0028] Generate a query area based on the user query location and the query radius;

[0029] Obtaining the minimum number of users and the minimum number of requested contents in the query area based on historical statistical experience;

[0030] Respectively determine all users whose distance to the user is less than or equal to the query radius as the first user neighborhood of the user, and all users whose distance to the user is greater than the query radius as the second user neighborhood of the user;

[0031] If it is determined that the first user neighborhood is greater than or equal to the minimum number of users, and the second user neighborhood is greater than or equal to the minimum number of requested contents, then the query area is a densely populated area; otherwise, the query area is a sparsely populated area;

[0032] Divide the query area into n×n cells. If the query area is the densely populated area, sort the position of each cell in descending order according to the current request number, determine k-1 positions in the sorted list that are closest to the user query position number, and use the k-anonymity algorithm with the user query position to generate the anonymous area;

[0033] If the query area is the sparsely populated area, a virtual location algorithm is used to sort the location of each cell in descending order according to the historical query probability, and k-1 locations closest to the user query location number in the sorted list are determined, and the k-anonymity algorithm is used to generate the anonymous area.

[0034] According to a user location information protection method provided by the present invention, the receiving of encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority and forwarding the encrypted location point of interest information to the user comprises:

[0035] The location service provider receives the encrypted query request, decrypts the encrypted query request using a private key, verifies the pseudonym through the certificate issuing authority, and receives the key sent by the certificate issuing authority;

[0036] The location service provider obtains the location point of interest information in the service database according to the anonymous area, the query request content and the query radius, and symmetrically encrypts the location point of interest information using the key to obtain the encrypted location point of interest information;

[0037] The encrypted location point of interest information is received from the location service provider, and the encrypted location point of interest information is forwarded to the user.

[0038] In a second aspect, the present invention provides a method for protecting user location information, comprising:

[0039] Obtain authentication information and send a first query request to the anonymous server;

[0040] After the anonymous server generates an anonymous area using a region-adaptive anonymous algorithm and sends an encrypted query request generated according to the anonymous area to a location service provider, the anonymous server receives the encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority;

[0041] The encrypted location point of interest information forwarded by the anonymous server from the location service provider is received, and the encrypted location point of interest information is decrypted to obtain the target location information.

[0042] According to a user location information protection method provided by the present invention, the step of obtaining authentication information and sending a first query request to an anonymous server includes:

[0043] Sending a location request to the location service provider and registering with the certificate issuing authority, the user receiving a pseudonym including a certificate expiration date, a certificate and a key issued by the certificate issuing authority;

[0044] The first query request determined based on the location mapping table is sent to the anonymous server.

[0045] In a third aspect, the present invention further provides a user location information protection system, comprising:

[0046] A receiving module, configured to wait for a user to obtain authentication information and receive a first query request sent by the user;

[0047] an anonymous module, used to respond to the first query request, determine an anonymous area using a region-adaptive anonymous algorithm, and send an encrypted query request generated according to the anonymous area to a location service provider;

[0048] The forwarding module is used to receive the encrypted location point of interest information obtained by the location service provider based on the certification of the certificate issuing agency, and forward the encrypted location point of interest information to the user so that the user can obtain the target location information based on the encrypted location point of interest information.

[0049] In a fourth aspect, the present invention further provides a user location information protection system, comprising:

[0050] A sending module, used to obtain authentication information and send a first query request to an anonymous server;

[0051] An acquisition module, configured to receive encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority after the anonymous server generates an anonymous area using a region-adaptive anonymous algorithm and sends an encrypted query request generated according to the anonymous area to the location service provider;

[0052] The processing module is used to receive the encrypted location point of interest information forwarded by the anonymous server from the location service provider, decrypt the encrypted location point of interest information, and obtain the target location information.

[0053] In a fifth aspect, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for protecting user location information as described in any one of the above is implemented.

[0054] In a sixth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the user location information protection methods described above.

[0055] In a seventh aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the user location information protection methods described above.

[0056] The user location information protection method and system provided by the present invention improve security when resisting inference attacks by decoupling user personal data and location data, reduce communication overhead and computing overhead of user terminals, and effectively achieve a balance between user location privacy and service quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0058] Figure 1 This is a TTP architecture diagram for deploying multiple anonymizers provided by the present invention;

[0059] Figure 2 This is one of the flow charts of the user location information protection method provided by the present invention;

[0060] Figure 3 It is a principle diagram of the user location information protection method provided by the present invention;

[0061] Figure 4 This is the second flow chart of the user location information protection method provided by the present invention;

[0062] Figure 5 It is one of the structural schematic diagrams of the user location information protection system provided by the present invention;

[0063] Figure 6 This is the second structural diagram of the user location information protection system provided by the present invention;

[0064] Figure 7 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] In view of the many deficiencies in the protection of user location information in the prior art, the present invention proposes a new method for protecting user location information for mobile social networks. The method is implemented based on the TTP architecture of multiple anonymizers deployed, such as Figure 1As shown in Figure 1, the architecture mainly includes four entities: user User, Certificate Authority (CA), anonymous server group (Multiple Anonymizers, MAs) and location service provider LSP, where the anonymous server MAs is located between the user User and the location service provider LSP, with a total of N anonymizers. By adopting this architecture, the performance bottleneck caused by single point failure is solved and the information transmission performance is improved.

[0067] User: A user can be an operating device with wireless communication, computing and storage capabilities, but more importantly, with positioning capabilities; the user performs various functions such as location prediction, selection of virtual locations, caching and refinement of query results.

[0068] Certificate issuing authority CA: This entity is completely trustworthy, and its main function is to register different users and LSPs; in the model of the present invention, CA can also issue pseudonyms and corresponding certificates and keys to users.

[0069] Anonymous server group MAs: MAs are semi-trusted entities that can be deployed on intermediate nodes of the network; the main function of MAs is to forward query requests and results between users and LSPs, and MAs can perform anonymization to obfuscate the exact location of users; in the model of the present invention, MAs can also perform calculations, local caching, generate random numbers, and other functions.

[0070] Location Service Provider LSP: LSP is an online location service solution provider, such as Twitter, Foursquare or Google Maps, which operates some location service-related resources. In the model of the present invention, LSP is considered to be an honest but curious entity, which may also leak sensitive user information.

[0071] To summarize, in this model, the certificate issuing authority CA and the user User are considered to be fully trusted entities; in addition, it is assumed that the two communication channels between CA and User and between CA and LSP are secure, and MAs cannot collude with LSP; at the same time, existing security authentication technologies such as two-factor authentication and multi-factor authentication can be used to ensure that users and LSPs are authenticated at CA.

[0072] Figure 2 This is one of the flow charts of the method for protecting user location information provided by the present invention, and the corresponding execution subject is the anonymous server MAs, such as Figure 2 As shown, including:

[0073] Step 101, after the user obtains authentication information, a first query request sent by the user is received;

[0074] Step 102, responding to the first query request, determining an anonymous area using a region-adaptive anonymity algorithm, and sending an encrypted query request generated according to the anonymous area to a location service provider;

[0075] Step 103, receiving the encrypted location POI information obtained by the location service provider through authentication by a certificate issuing authority, and forwarding the encrypted location POI information to the user, so that the user can obtain target location information according to the encrypted location POI information.

[0076] Specifically, when a user accesses the network and obtains the corresponding authentication information after registration and authentication, the anonymous server receives the first query request initiated by the user. Based on the first query request, the anonymous server will calculate the corresponding anonymous area according to the regional adaptive anonymous algorithm, add other information of the user on the basis of the anonymous area to generate an encrypted query request, and send the encrypted query request to the location service provider. The location service provider decrypts the encrypted query request and verifies the validity of the user information through the certificate issuing agency. The location service provider symmetrically encrypts the location points of interest in the service database based on the verified information, and after obtaining the encrypted location points of interest information, it is sent to the anonymous server, which forwards it to the user. The user selects the location points of interest he needs according to his own location, and obtains the target location information.

[0077] The present invention adopts distributed transmission based on a centralized architecture and a phased encrypted communication mode, combined with a regional adaptive anonymity scheme, to solve the problems of high communication overhead, high computing overhead of user equipment, and high correlation between user personal data and location data in traditional schemes.

[0078] Based on the above embodiment, step 101 includes:

[0079] The user sends a location request to the location service provider and registers with the certificate issuing authority, and the user receives a pseudonym, certificate and key including a certificate period issued by the certificate issuing authority;

[0080] The first query request sent by the user based on the location mapping table is received.

[0081] The receiving the first query request sent by the user based on the location mapping table includes:

[0082] Obtaining any user location coordinate value, calculating a hash value of the any user location coordinate value, and performing a modulo operation on the number of anonymous servers to obtain any anonymous server serial number;

[0083] Constructing the location mapping table based on any anonymous server serial number and any user location coordinate value;

[0084] The user determines a receiving anonymous server according to the location mapping table, and the receiving anonymous server receives the pseudonym, the certificate, the certificate period, query request content, query radius and anonymity level sent by the user.

[0085] Specifically, when a user User uses a single-point LBS service for the first time, the user must register with the certificate issuing authority CA. After registration, the user can obtain a pseudonym and a corresponding certificate, as well as his or her own key, and can apply to the CA for and update the pseudonym and key as many times as needed. Multiple applications here mean that if the certificate expires, you can apply again.

[0086] If the user applies for or updates a pseudonym from the CA for the jth time, that is, at any time, the CA will issue the pseudonym to the user. and the corresponding certificates The certificate period is T, and the key is assigned to the User. The pseudonym, certificate and key are all valid within time T, and the pseudonym is specified. It is unique within time T and there will be no duplicate names.

[0087] Furthermore, by constructing a location mapping table, query requests from different locations are mapped to different anonymous servers. Assume that there are N anonymous servers A1, A2, ..., A N , by calculating the hash value of the location coordinate (x+y), performing a modulo operation on N, and obtaining the serial number l (l=1,2,...,N) of the anonymous server, the query request sent by the location (x+y) is mapped to the corresponding anonymous server A l .

[0088] A l =Hash(x+y)modN,(1≤l≤N)

[0089] In order to ensure security, the present invention sends user information and location information to the anonymous server A respectively. l , the user User first sends a query request without location to the anonymous server, that is, the first query request, denoted as

[0090]

[0091] Among them, Q is the user's query request content, R is the query radius, and k is the user-defined anonymity level.

[0092] The present invention splits the traditional location triple {identity, location, timestamp} and sends the identity and location twice, thus breaking the association between user information and location and effectively resisting inference attacks.

[0093] Based on any of the above embodiments, step 102 includes:

[0094] receiving the first query requirement, and if it is determined that the same pseudonym as the user exists within the certificate period, sending a first mark to the user, and generating the anonymous region based on the region adaptive anonymity algorithm;

[0095] Otherwise, cache the first query demand, send a second tag to the user, receive a second query demand sent by the user, wherein the second query demand includes the second tag and the user query location, and cache after associating the user query location, the pseudonym, and the certificate expiration date;

[0096] The pseudonym, the certificate, the certificate period, the query request content, the query radius and the anonymous area are combined to obtain a comprehensive query request, and the comprehensive query request is encrypted using the public key of the location service provider to obtain an encrypted query request.

[0097] Wherein, generating the anonymous area based on the area adaptive anonymity algorithm includes:

[0098] receiving the first query request sent by the user and carrying the user query location;

[0099] Generate a query area based on the user query location and the query radius;

[0100] Obtaining the minimum number of users and the minimum number of requested contents in the query area based on historical statistical experience;

[0101] Respectively determine all users whose distance to the user is less than or equal to the query radius as the first user neighborhood of the user, and all users whose distance to the user is greater than the query radius as the second user neighborhood of the user;

[0102] If it is determined that the first user neighborhood is greater than or equal to the minimum number of users, and the second user neighborhood is greater than or equal to the minimum number of requested contents, then the query area is a densely populated area; otherwise, the query area is a sparsely populated area;

[0103] Divide the query area into n×n cells. If the query area is the densely populated area, sort the position of each cell in descending order according to the current request number, determine k-1 positions in the sorted list that are closest to the user query position number, and use the k-anonymity algorithm with the user query position to generate the anonymous area;

[0104] If the query area is the sparsely populated area, a virtual location algorithm is used to sort the location of each cell in descending order according to the historical query probability, and k-1 locations closest to the user query location number in the sorted list are determined, and the k-anonymity algorithm is used to generate the anonymous area.

[0105] Specifically, Figure 3 As shown, when the anonymous server A l After receiving the query request from the user User, search the local cache list to see if there is a pseudonym in T If the user has initiated a request, the first mark is sent to the user, which is generally set to 1. At the same time, the user's query location within the validity period is generated according to the user's request R,k, and an anonymous region Region is generated; if not, the information Cache it locally and send a second tag to the user, usually a random number M (M≠1). After receiving M, the user sends a second query message

[0106]

[0107] Anonymous Server A l receive Then, the user's query location Location and pseudonym The certificate is associated with a validity period of T and is cached locally.

[0108] Anonymous Server A l Generate an anonymous region Region based on the Location and R, k requested by the user, and combine Region with other user information to form a new query request, using the LSP's public key PK S Encryption; then, the encrypted query request message MSG A2S Sent to LSP.

[0109]

[0110] It should be noted that the anonymous server generates the anonymous region Region using a regional adaptive anonymity scheme based on user distance and request content:

[0111] First, the anonymous server receives the user u i Query request information sent

[0112] The anonymous server uses the user u i The sent location Location and query radius R generate the area Reg, u i ∈Reg;

[0113] The anonymous server obtains the minimum number of users MinU and the minimum number of requested contents MinC in the region Reg based on historical experience;

[0114] The anonymizer calculates user u i The R neighborhood (first neighborhood) and the θ neighborhood (second neighborhood) of Reg satisfy u i All users whose distance is not greater than R are called u i The R neighborhood of R (u i ) means:

[0115] N R (u i )={u j ∈Reg|dist(u i ,u j )≤R}

[0116] Reg satisfies the request content with u i All users who do not meet this condition are called u i The θ neighborhood of θ (u i ) means:

[0117] N θ (u i )={u j ∈Reg|boolean(u i ,u j )=false}

[0118] Among them, boolean() is a Boolean value, which indicates whether the user's request content is the same.

[0119] The anonymous server further determines whether Reg is a sparsely populated area or a densely populated area. If Reg satisfies the conditions |N R (u i )|≥MinU and|N θ (u i )|≥MinC, then Reg is a densely populated area; otherwise, Reg is judged to be a sparsely populated area;

[0120] Reg is divided into n×n cells. If Reg is a densely populated area, the position of each cell in Reg is sorted in descending order according to the current number of requests, and k-1 positions with the closest number to the user's query position in the sorted list are selected to generate an anonymous area together with the user's query position to achieve k-anonymity; if Reg is a sparsely populated area, the classic virtual position algorithm is adopted to sort the position of each cell in Reg in descending order according to the historical query probability, and k-1 virtual positions with the closest number to the user's query position in the sorted list are selected to achieve k-anonymity.

[0121] Here, the k-anonymity technology used was originally proposed by P. Samarati and L. Seweney at the Symposium on Principles of Database Systems (PODS) in 1998. It is mainly used in relational databases to process private data that needs to be published in the database in an anonymous manner. It requires a certain number of records (at least k), and these records are indistinguishable from the quasi-identifiers in the published data. Attackers cannot identify the specific individual to whom private information belongs, thereby protecting personal privacy, and k-anonymity specifies the maximum information leakage risk that a user can bear through the parameter k. In 2002, L. Seweney proposed the k-anonymity privacy protection model. In 2003, Marco Gruteser first applied the k-anonymity method to LBS privacy protection and proposed the location k-anonymity model. The principle is to generate an anonymous region (Cloaking Region, CR) with at least k users, use the anonymous region as the user's real location, and directly send the anonymous region to the LBS service provider when the user submits a query request. The probability that the service provider identifies a specific user in this way is no more than 1 / k. Since the idea of ​​the k-anonymity method has high security, many location privacy protection schemes are currently based on this method.

[0122] The present invention divides densely populated areas and sparsely populated areas based on user distance and request content, and adopts different anonymity schemes for different areas. By adopting different anonymity schemes for different areas, it is possible to achieve effective anonymity and protect user privacy while reducing the loss of service quality obtained by users, thereby better achieving a balance between user location privacy and service quality, overcoming the defects of traditional schemes that are too costly and need to sacrifice a certain LBS applicability, resulting in LBS services being difficult to achieve user satisfaction.

[0123] Based on any of the above embodiments, step 103 includes:

[0124] The location service provider receives the encrypted query request, decrypts the encrypted query request using a private key, verifies the pseudonym through the certificate issuing authority, and receives the key sent by the certificate issuing authority;

[0125] The location service provider obtains the location point of interest information in the service database according to the anonymous area, the query request content and the query radius, and symmetrically encrypts the location point of interest information using the key to obtain the encrypted location point of interest information;

[0126] The encrypted location point of interest information is received from the location service provider, and the encrypted location point of interest information is forwarded to the user.

[0127] Specifically, Figure 3 As shown, upon receiving the query request message MSG A2S After that, LSP uses its own private key SK S Decrypt and verify the validity of the user's pseudonym through CA. If valid, CA sends the user key to LSP.

[0128] LSP queries the POIs in the service database based on the anonymous region Region, request content Q and query radius R, and then uses the user key Symmetrically encrypt these POIs and get Then, LSP sends the result to anonymous server A l ;

[0129] Anonymous Server A l Receive message Forward the message to user User, and user User receives the message Use your own key Decrypt and you will get the POIs you need.

[0130] In order to reduce communication overhead and computing overhead, the present invention does not adopt an encryption method when the user sends a query request. The location privacy protection scheme in the mobile social network scenario proposed by the present invention enhances the security of user information through dynamic pseudonym technology; by sending identity and location separately, the use of necessary encryption means when sending {identity, location, timestamp} at the same time is avoided; by allocating keys to LSP by CA, the transmission of user keys through channels is avoided, the risk of user privacy leakage when the channel is monitored is reduced, and the communication overhead and computing overhead of the old scheme are greatly reduced.

[0131] Figure 4This is the second flow chart of the user location information protection method provided by the present invention, and the corresponding execution subject is the user, such as Figure 4 As shown, including:

[0132] Step 201, obtaining authentication information, and sending a first query request to an anonymous server;

[0133] Step 202, after the anonymous server generates an anonymous area using a region-adaptive anonymous algorithm and sends an encrypted query request generated according to the anonymous area to a location service provider, the anonymous server receives the encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority;

[0134] Step 203: receiving the encrypted location point of interest information forwarded by the anonymous server from the location service provider, decrypting the encrypted location point of interest information, and obtaining the target location information.

[0135] Specifically, when a user accesses the network and obtains the corresponding authentication information after registration and authentication, the anonymous server receives the first query request initiated by the user. Based on the first query request, the anonymous server will calculate the corresponding anonymous area according to the regional adaptive anonymous algorithm, add other information of the user on the basis of the anonymous area to generate an encrypted query request, and send the encrypted query request to the location service provider. The location service provider decrypts the encrypted query request and verifies the validity of the user information through the certificate issuing agency. The location service provider symmetrically encrypts the location points of interest in the service database based on the verified information, and after obtaining the encrypted location points of interest information, it is sent to the anonymous server, which forwards it to the user. The user selects the location points of interest he needs according to his own location, and obtains the target location information.

[0136] The present invention adopts distributed transmission based on a centralized architecture and a phased encrypted communication mode, combined with a regional adaptive anonymity scheme, to solve the problems of high communication overhead, high computing overhead of user equipment, and high correlation between user personal data and location data in traditional schemes.

[0137] Based on any of the above embodiments, step 201 includes:

[0138] A location request is sent to the location service provider, and registration is performed with the certificate issuing authority, and the user receives a pseudonym, a certificate and a key including a certificate period issued by the certificate issuing authority.

[0139] The first query request determined based on the location mapping table is sent to the anonymous server.

[0140] Specifically, when a user User uses a single-point LBS service for the first time, the user must register with the certificate issuing authority CA. After registration, the user can obtain a pseudonym and a corresponding certificate, as well as his or her own key, and can apply to the CA for and update the pseudonym and key as many times as needed. Multiple applications here mean that if the certificate expires, you can apply again.

[0141] If the user applies for or updates a pseudonym from the CA for the jth time, that is, at any time, the CA will issue the pseudonym to the user. and the corresponding certificates The certificate period is T, and the key is assigned to the User. The pseudonym, certificate and key are all valid within time T, and the pseudonym is specified. It is unique within time T and there will be no duplicate names.

[0142] Furthermore, by constructing a location mapping table, query requests from different locations are mapped to different anonymous servers. Assume that there are N anonymous servers A1, A2, ..., A N , by calculating the hash value of the location coordinate (x+y), performing a modulo operation on N, and obtaining the serial number l (l=1,2,...,N) of the anonymous server, the query request sent by the location (x+y) is mapped to the corresponding anonymous server A l .

[0143] A l =Hash(x+y)modN,(1≤l≤N)

[0144] In order to ensure security, the present invention sends user information and location information to the anonymous server A respectively. l , the user User first sends a query request without location to the anonymous server, that is, the first query request, denoted as

[0145]

[0146] Among them, Q is the user's query request content, R is the query radius, and k is the user-defined anonymity level.

[0147] The present invention splits the traditional location triple {identity, location, timestamp} and sends the identity and location twice, thus breaking the association between user information and location and effectively resisting inference attacks.

[0148] The user location information protection system provided by the present invention is described below. The user location information protection system described below and the user location information protection method described above can be referenced to each other.

[0149] Figure 5 is one of the structural diagrams of the user location information protection system provided by the present invention, such as Figure 5 As shown, it includes: a receiving module 51, an anonymous module 52 and a forwarding module 53, wherein:

[0150] The receiving module 51 is used for waiting for a user to obtain authentication information and receiving a first query request sent by the user;

[0151] The anonymous module 52 is used to respond to the first query request, determine the anonymous area by using the area adaptive anonymous algorithm, and send an encrypted query request generated according to the anonymous area to the location service provider;

[0152] The forwarding module 53 is used to receive the encrypted location POI information obtained by the location service provider based on the certification of the certificate issuing agency, and forward the encrypted location POI information to the user so that the user can obtain the target location information based on the encrypted location POI information.

[0153] The present invention improves security when resisting inference attacks by decoupling user personal data and location data, reduces communication overhead and computing overhead of user terminals, and effectively achieves a balance between user location privacy and service quality.

[0154] Figure 6 This is the second structural diagram of the user location information protection system provided by the present invention, such as Figure 6 As shown, it includes: a sending module 61, an acquisition module 62 and a processing module 63, wherein:

[0155] The sending module 61 is used to obtain authentication information and send a first query request to the anonymous server;

[0156] The acquisition module 62 is used for receiving the encrypted location point of interest information obtained by the location service provider through authentication by the certificate issuing authority after the anonymous server generates the anonymous area using the region adaptive anonymous algorithm and sends the encrypted query request generated according to the anonymous area to the location service provider;

[0157] The processing module 63 is used to receive the encrypted location point of interest information forwarded by the anonymous server from the location service provider, decrypt the encrypted location point of interest information, and obtain the target location information.

[0158] The present invention improves security when resisting inference attacks by decoupling user personal data and location data, reduces communication overhead and computing overhead of user terminals, and effectively achieves a balance between user location privacy and service quality.

[0159] Figure 7An example of a physical structure diagram of an electronic device is shown in FIG. Figure 7 As shown, the electronic device may include: a processor 710, a communication interface 720, a memory 730 and a communication bus 740, wherein the processor 710, the communication interface 720 and the memory 730 complete mutual communication through the communication bus 740. The processor 710 may call the logic instructions in the memory 730 to execute the user location information protection method, which includes: waiting for the user to obtain authentication information, receiving a first query request sent by the user; responding to the first query request, determining an anonymous area using a regional adaptive anonymity algorithm, and sending an encrypted query request generated according to the anonymous area to a location service provider; receiving the encrypted location interest point information obtained by the location service provider through authentication by a certificate issuing authority, and forwarding the encrypted location interest point information to the user, so that the user can obtain the target location information according to the encrypted location interest point information.

[0160] In addition, the logic instructions in the above-mentioned memory 730 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0161] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the user location information protection method provided by the above methods, which includes: waiting for the user to obtain authentication information, receiving a first query request sent by the user; responding to the first query request, determining an anonymous area using a regional adaptive anonymity algorithm, and sending an encrypted query request generated according to the anonymous area to a location service provider; receiving the encrypted location point of interest information obtained by the location service provider based on the certification of the certificate issuing agency, and forwarding the encrypted location point of interest information to the user, so that the user can obtain the target location information based on the encrypted location point of interest information.

[0162] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the user location information protection method provided by the above-mentioned methods. The method includes: waiting for the user to obtain authentication information, receiving a first query request sent by the user; responding to the first query request, determining an anonymous area using a regional adaptive anonymity algorithm, and sending an encrypted query request generated according to the anonymous area to a location service provider; receiving the encrypted location point of interest information obtained by the location service provider based on the authentication of the certificate issuing authority, and forwarding the encrypted location point of interest information to the user, so that the user can obtain the target location information based on the encrypted location point of interest information.

[0163] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0164] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0165] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for protecting user location information, applied to an anonymous server, characterized in that: include: After the user obtains authentication information, a first query request sent by the user is received; In response to the first query request, determine an anonymous area using a region-adaptive anonymity algorithm, and send an encrypted query request generated according to the anonymous area to a location service provider; Receiving the encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority, and forwarding the encrypted location point of interest information to the user, so that the user can obtain target location information according to the encrypted location point of interest information; The target location information is a target location point of interest; The user to be used obtains authentication information and receives a first query request sent by the user, including: the user sends a location request to the location service provider and registers with the certificate issuing authority, and the user receives a pseudonym, certificate and key including a certificate period issued by the certificate issuing authority; and receives the first query request sent by the user based on the location mapping table; The receiving the first query request sent by the user based on the location mapping table includes: obtaining a location coordinate value of any user, calculating a hash value of the location coordinate value of any user, and performing a modulo operation on the number of anonymous servers to obtain a serial number of any anonymous server; constructing the location mapping table based on the serial number of any anonymous server and the location coordinate value of any user; the user determines a receiving anonymous server according to the location mapping table, and the receiving anonymous server receives the pseudonym, the certificate, the certificate term, the query request content, the query radius, and the anonymity level sent by the user; The responding to the first query request, using a region-adaptive anonymity algorithm to determine an anonymous region, and sending an encrypted query request generated according to the anonymous region to a location service provider, includes: receiving the first query request, and if it is determined that the same pseudonym as the user exists within the certificate period, sending a first tag to the user, and generating the anonymous region based on the region-adaptive anonymity algorithm; otherwise, caching the first query request, sending a second tag to the user, receiving a second query request sent by the user, wherein the second query request includes the second tag and the user query location, and caching the user query location, the pseudonym, and the certificate period after associating them; synthesizing the pseudonym, the certificate, the certificate period, the query request content, the query radius, and the anonymous region to obtain a comprehensive query request, and encrypting the comprehensive query request using the public key of the location service provider to obtain an encrypted query request; The receiving of the encrypted location POI information obtained by the location service provider through authentication by a certificate issuing authority, and forwarding the encrypted location POI information to the user, includes: the location service provider receiving the encrypted query request, decrypting the encrypted query request with a private key, verifying the pseudonym with the certificate issuing authority, and receiving the key sent by the certificate issuing authority; the location service provider obtaining the location POI information in a service database based on the anonymous area, query request content and query radius, and symmetrically encrypting the location POI information with the key to obtain the encrypted location POI information; receiving the encrypted location POI information sent by the location service provider, and forwarding the encrypted location POI information to the user.

2. The user location information protection method according to claim 1, characterized in that: The generating the anonymous region based on the region adaptive anonymity algorithm comprises: receiving the first query request sent by the user and carrying the user query location; Generate a query area based on the user query location and the query radius; Obtaining the minimum number of users and the minimum number of requested contents in the query area based on historical statistical experience; Respectively determine all users whose distance to the user is less than or equal to the query radius as the first user neighborhood of the user, and all users whose distance to the user is greater than the query radius as the second user neighborhood of the user; If it is determined that the first user neighborhood is greater than or equal to the minimum number of users, and the second user neighborhood is greater than or equal to the minimum number of requested contents, then the query area is a densely populated area; otherwise, the query area is a sparsely populated area; The query area is divided into cells, if the query area is the densely populated area, the position of each cell is sorted in descending order according to the current request number, and the cell closest to the user's query position number in the sorted list is determined. A location and a user query location are used to generate the anonymous area using a k-anonymity algorithm; If the query area is a sparsely populated area, a virtual location algorithm is used to sort the location of each cell in descending order according to the historical query probability, and determine the cell closest to the user's query location number in the sorted list. The k-anonymity algorithm is used to generate the anonymous area.

3. A user location information protection method, applied to the user side, and corresponding to the user location information protection method as claimed in claim 1, characterized in that: include: Obtain authentication information and send a first query request to the anonymous server; After the anonymous server generates an anonymous area using a region-adaptive anonymous algorithm and sends an encrypted query request generated according to the anonymous area to a location service provider, the anonymous server receives the encrypted location point of interest information obtained by the location service provider through authentication by a certificate issuing authority; receiving the encrypted location point of interest information forwarded by the anonymous server from the location service provider, decrypting the encrypted location point of interest information, and obtaining target location information; The target location information is a target location point of interest; The obtaining of authentication information and sending a first query request to the anonymous server includes: sending a location request to the location service provider and registering with the certificate issuing authority, and the user receiving a pseudonym, certificate and key including a certificate period issued by the certificate issuing authority; The first query request determined based on the location mapping table is sent to the anonymous server.

4. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the user location information protection method as described in any one of claims 1 to 3 is implemented.

5. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the user location information protection method as described in any one of claims 1 to 3 is implemented.

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