Privacy protection data association system and privacy protection data association device

Abstract

To generate statistical information that excludes a correspondence relation with individuals without revealing contents of personal information to other devices.SOLUTION: In a data association system including a plurality of devices which maintain user data including a user ID and personal information about a user, each device includes: a de-identification processing unit which performs de-identification processing on the user data and generates de-identified data; an encryption unit which performs first encryption for encrypting the de-identified data using a self-encryption key held by a self-device and second encryption for encrypting the de-identified data subjected to the first encryption received from a partner device using a self-encryption key; and an aggregation processing unit which collates the de-identified data subjected to the second encryption with the de-identified data subjected to the second encryption received from the partner device and aggregates the number of de-identified data subjected to the second encryption whose user ID corresponding parts specified on the basis of structural information of the user data match each other as the number of target users.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a privacy preserving data linkage system and a privacy preserving data linkage device. [Background technology]

[0002] When performing statistical analysis on user data managed in a database in information processing devices (devices broadly including computers, servers, etc., hereinafter referred to as "devices") of multiple organizations, if the user data includes personal information, some measures must be taken from the viewpoint of privacy protection. As an example of such measures, a technology is known that integrates both data to be anonymized and data that may be disclosed while keeping the data to be anonymized confidential by using a system configuration having an interface that can simultaneously handle both data (see Patent Document 1 below). In addition, a technology is known that protects personal information when integrating user data including personal information between multiple devices by performing both reversible encryption processing and irreversible encryption processing on the ID of each personal information, making it difficult for a third party to restore the original ID (see Patent Document 2 below). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-081301 A [Patent Document 2] JP 2010-211590 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, it is essential to select data to be concealed from the input user data, and it is not assumed that the user data does not include data that may be disclosed, that is, the entire input user data is to be concealed, and in this respect there is room for improvement. In the technology of Patent Document 2, it is essential to perform both reversible encryption processing and irreversible encryption processing, and since the reversible encryption processing remains, there is room for improvement in that there remains a possibility of restoration. In addition, in common with Patent Documents 1 and 2, there is room for improvement from the viewpoint of privacy protection in that the possibility of inferring the correspondence between the processing result and an individual cannot be completely eliminated.

[0005] The present disclosure aims to generate statistical information that excludes correspondence with individuals by coordinating between multiple devices that hold personal information, without disclosing the contents of the personal information to other devices. [Means for solving the problem]

[0006] The privacy-preserving data linkage system according to the present disclosure includes a plurality of devices that hold user data including user IDs and personal information related to users, and each of the devices includes a de-identification processing unit that de-identifies the user data to generate de-identified data, an encryption unit that performs a first encryption using its own encryption key held by its own device, and a second encryption using its own encryption key on the first encrypted de-identified data received from a partner device, and a counting processing unit that matches the second encrypted de-identified data with the second encrypted de-identified data received from the partner device, and counts the number of second encrypted de-identified data for which a user ID corresponding portion identified based on predetermined structural information of the user data matches as the number of target users. Effect of the Invention

[0007] According to the present disclosure, by coordinating between multiple devices that hold personal information, it is possible to generate statistical information that excludes correspondence with individuals, without disclosing the contents of the personal information to other devices. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a privacy protection data linking system according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a flow diagram showing processing executed in a privacy-preserving data linkage system according to an embodiment of the present disclosure. [Diagram 3] 1A is a diagram for explaining the process of generating de-identified data by a device of company A, and FIG. 1B is a diagram for explaining the process of generating de-identified data by a device of company B. FIG. [Figure 4] 1A is a diagram for explaining grouping of de-identified data by a device of company A, and FIG. 1B is a diagram for explaining grouping of de-identified data by a device of company B. FIG. [Diagram 5] FIG. 13 is a diagram for explaining encryption processing of de-identified data by devices of companies A and B. [Figure 6] 6 is a diagram for supplementarily explaining the encryption process in FIG. 5. [Figure 7] (a) is a diagram for explaining the process of counting the number of users who have used the service and visited the store, (b) is a diagram for explaining the process of counting the number of users who have used the service but have not visited the store, (c) is a diagram for explaining the process of counting the number of users who have not used the service but have visited the store, and (d) is a diagram for explaining the process of counting the number of users who have not used the service and have not visited the store. [Figure 8] FIG. 13 is a diagram for explaining a confidentiality process. [Figure 9] FIG. 11 is a configuration diagram of a privacy protection data linkage system according to a first modified example. [Figure 10] FIG. 11 is a flow diagram showing processing executed in a privacy protection data linkage system according to a first modified example. [Figure 11]FIG. 11 is a configuration diagram of a privacy protection data linkage system according to a second modified example. [Figure 12] FIG. 11 is a flow chart showing processing executed in a privacy protection data linkage system according to a second modified example. [Figure 13] FIG. 2 illustrates an example of a hardware configuration of each device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of a privacy protection data linkage system and a privacy protection data linkage device according to the present disclosure will be described with reference to the drawings.

[0010] (Configuration of privacy protection data linkage system) As shown in FIG. 1, the privacy protection data linkage system 1 according to the present disclosure includes a plurality of devices 10 (corresponding to privacy protection data linkage devices) that can communicate with each other, and as described later, statistical information on the number of target users is generated by linking one of the plurality of devices 10 with a counterpart device. That is, after both the one device and the counterpart device execute "generation of de-identified data" and "encryption of de-identified data" described later, the one device that receives the double-encrypted de-identified data from the counterpart device executes "counting process" and "secrecy process" to generate statistical information. Note that, for convenience of explanation, two devices 10A and 10B are shown in FIG. 1, but three or more devices may be provided. In the process described later, an example will be described in which the device 10A of company A operates as "one device" and the device 10B of company B operates as "other device", but each device 10 has the same functional block configuration described later and may operate as "one device" or as "other device".

[0011] In addition, each device 10 holds user data including a "user ID" and "personal information" related to the user in an internal memory (not shown). The above-mentioned "user ID" has a data format common to each device, but the above-mentioned "personal information" is not necessarily common to each device because the type of information is predetermined for each device. For example, the user data held by the device 10A of company A shown in the upper part of FIG. 3(a) includes "name" and "date of birth" corresponding to the user ID, and "gender," "age," and "usage status" corresponding to personal information, while the user data held by the device 10B of company B shown in the upper part of FIG. 3(b) includes "name" and "date of birth" corresponding to the user ID, and "store visit information" and "purchase information" corresponding to personal information. In this way, the "name" and "date of birth" corresponding to the user ID are in a common data format, but the type of information corresponding to personal information is different between the two. For example, the "usage status" included in the personal information of company A above is information indicating whether or not a service provided by company A is being used (presence or absence of use), the "store visit information" included in the personal information of company B above is information indicating whether or not a store operated by company B has been visited (presence or absence of visit), and the "purchase information" is information indicating products purchased when visiting the store (personal computer (PC), microwave oven, etc.). Note that structural information of the user data held by each device 10 is shared between the devices in advance, and based on the structural information, it is possible to identify the "user ID corresponding portion" in the double encrypted de-identified data generated in each device 10 described later, and it is possible to match the "user ID corresponding portion" between the double encrypted de-identified data described later.

[0012] Below, the functional block configuration of each device 10 will be described using device 10A of company A as an example. As shown in FIG. 1, device 10A includes a de-identification processing unit 11, an encryption unit 12, a counting processing unit 13, and a confidentiality processing unit .

[0013] Of these, the de-identification processing unit 11 is a functional unit that performs irreversible conversion processing into a user ID and processing for privacy protection of personal information on user data held by its own device 10A, and generates de-identified data corresponding to user data whose personal information satisfies a condition that the personal information in the user data must satisfy in order to extract a target user.

[0014] In this embodiment, the device 10A of company A and the device 10B of company B cooperate with each other to extract target users based on a total of four conditions corresponding to a combination of personal information "usage status" (used / not used) in the user data of company A and personal information "visit information" (visited / not visited), and a process of counting the number of target users for each condition and generating statistical information will be described later. In addition, in this embodiment, as an example of "irreversible conversion processing", an example of executing hashing processing using a hash function shared in advance between the devices 10 will be described, but the irreversible conversion processing is not limited to hashing processing. In addition, as an example of "privacy protection", k-anonymization will be described, but other methods such as l-diversity and t-approximation may be used, or a combination of two or more methods may be used.

[0015] The encryption unit 12 is a functional unit that generates double-encrypted de-identified data after double encryption using a self encryption key held by the own device 10A and a partner encryption key held by the partner device 10B by coordinating between the own device 10A, which is one device, and the partner device 10B as follows. That is, the encryption unit 12 performs a first encryption based on the self encryption key and the keyed one-way commutative operation on the deidentified data generated by the deidentification processing unit 11 of its own device 10A, exchanges the deidentified data after the first encryption with the other device 10B (i.e., the other device 10B that performed the first encryption based on the other device encryption key and the keyed one-way commutative operation on the deidentified data generated by the deidentification processing unit 11 of the device 10B), and performs a second encryption based on the self encryption key and the keyed one-way commutative operation on the deidentified data after the first encryption received from the other device 10B, to generate doubly encrypted deidentified data after doubly encryption using the self encryption key and the other device encryption key. At this time, the encryption unit 12 of the other device 10B also performs a second encryption based on the other device encryption key and the keyed one-way commutative operation in the same manner as above, to generate doubly encrypted deidentified data after doubly encryption using the self encryption key and the other device encryption key. The encryption process by the encryption unit 12 for the de-identified data is performed by dividing the de-identified data into a "portion corresponding to a user ID" and a "portion corresponding to personal information."

[0016] In the encryption as described above, the deidentified data after the first encryption exchanged between the devices 10A and 10B is encrypted based on the other device's encryption key that is not disclosed to the own device, so the own device cannot decrypt the deidentified data and cannot recognize the contents of the deidentified data (personal information, etc.). Similarly, the other device cannot decrypt the deidentified data after the first encryption obtained by the exchange and cannot recognize the contents of the deidentified data (personal information, etc.). In this way, the encryption unit 12 can generate double encrypted deidentified data after double encryption using the own encryption key and the other device's encryption key, without disclosing to the other device 10B either the personal information in the unencrypted user data held by the own device 10A or the own encryption key. In addition, since both encryptions are based on keyed one-way commutative operations, it is possible to determine whether the doubly encrypted de-identified data generated in one's own device 10A and the doubly encrypted de-identified data generated in the other device 10B correspond to user data of the same user depending on whether the bit strings of the user ID corresponding portion identified based on structural information of the user data shared in advance between devices 10A and 10B match or mismatch.

[0017] The counting processing unit 13 is a functional unit that counts the number of target users by comparing the double encrypted deidentified data generated by the encryption unit 12 of the other device 10B with the double encrypted deidentified data generated by the encryption unit 12 of its own device 10A and counting the number of double encrypted deidentified data whose "portions corresponding to user IDs" match. As described above, it is possible to determine whether or not these two pieces of double encrypted deidentified data correspond to user data of the same user depending on whether the "portions corresponding to user IDs" specified based on the data structure of the user data match between the two pieces of double encrypted deidentified data. Therefore, the counting processing unit 13 counts the number of double encrypted deidentified data whose "portions corresponding to user IDs" match as a result of the above matching, that is, the number of double encrypted deidentified data determined to correspond to user data of the same user, thereby counting the "number of target users" corresponding to the number of double encrypted deidentified data whose personal information satisfies the condition of a target user.

[0018] The concealment processing unit 14 is a functional unit that performs concealment processing on the counting results obtained by the counting processing unit 13, and generates concealed statistical information. Note that in this embodiment, as an example of the "concealment processing", an example of performing concealment processing that adds noise having a certain level of intensity or more, that is, concealment processing based on differential privacy will be described, but the concealment processing is not limited to the concealment processing based on differential privacy.

[0019] Each device 10 constituting the privacy protection data link system 1 has the above-mentioned functional units, and the details of these functions will be made clear in the following description of the processes based on FIGS. 2 to 8.

[0020] (Processing executed in the privacy protection data linkage system) An example will be described below in which a device 10A of company A operates as a "first device" and a device 10B of company B operates as a "second device".

[0021] In the device 10A of company A, the de-identification processing unit 11 k-anonymizes the "target attribute information" which is personal information in the user data held by its own device 10A (step A1), executes a hashing process using a hash function shared in advance between the devices 10 for the "user ID" in the user data, and then discards the salt used in the hashing process (step A2). To supplement the processes of steps A1 and A2 above based on FIG. 3(a), in an example in which the user data to be processed includes the name "Yamada Taro" and the date of birth "January 1, 2000" corresponding to the "user ID", the name and date of birth are formatted as "Yamada Taro 20000101" in the format of "name + YYYYMMDD" for subsequent processing, and k-anonymizes the gender, age, and usage status corresponding to the "target attribute information", and further executes a hashing process on the "user ID" using the salt to convert the user ID into a hash value, and then discards the salt. As a result, de-identified data including the hash value "a12f7d9" corresponding to the "user ID" and the k-anonymized "target attribute information" is obtained.

[0022] As described above, in this embodiment, a total of four conditions according to the combination of personal information "usage status" (used / not used) in the user data of company A and personal information "visit information" (visited / not visited) in the user data of company B are used as conditions for extracting target users, and the number of target users is counted for each condition and statistical information is generated. Then, the non-identification processing unit 11 of the device 10A of company A binarizes the target attribute information (step A3) and separates it into bit strings of the target attribute information (step A4). Here, the processing of steps A3 and A4 will be supplementarily explained based on FIG. 4(a). Note that, in FIG. 4(a), for ease of explanation, an example is shown in which only "usage status" (used / not used) is focused on as the target attribute information corresponding to personal information. Similarly, FIG. 4(b) described later shows an example in which only "visit information" (visited / not visited) is focused on as the target attribute information corresponding to personal information.

[0023] As shown in the upper part of FIG. 4(a), when the de-identified data to be processed includes a "hash value" corresponding to a user ID and a "use status (1: yes, 0: no)" corresponding to the target attribute information, the de-identification processing unit 11 binarizes the target attribute information according to the use status (1: yes, 0: no). At this time, as shown in the middle part of FIG. 4(a), for example, the data of the hash value "4a3" has a use status, so it is converted into data in which the bit of "use status yes" is "1" and the bit of "use status no" is "0", while the data of the hash value "3c0" has no use status, so it is converted into data in which the bit of "use status yes" is "0" and the bit of "use status no" is "1". Then, the de-identification processing unit 11 separates the de-identified data for each bit string of the target attribute information (here, "10" or "01"), and as a result, as shown in the lower part of FIG. 4(a), it is separated into a group in which the bit string of the target attribute information is "10" and a group in which the bit string of the target attribute information is "01".

[0024] Similarly, in device 10B of company B, the de-identification processing unit 11 k-anonymizes the “target attribute information” in the user data held by device 10B (step B1), hashes the “user ID” in the user data using a hash function previously shared between devices 10, and then discards the salt used in the hashing (step B2). To add a supplement based on FIG. 3(b), in an example where the raw data to be processed includes the name "Yamada Taro" and date of birth "January 1, 2000" corresponding to the "user ID," the name and date of birth are formatted as "Yamada Taro 20000101" in the format "name+YYYYMMDD" (i.e., a format where YYYY represents the year, MM represents the month, and DD represents the day) for subsequent processing, the store visited and purchase information corresponding to the "target attribute information" are k-anonymized, and further, a hashing process is performed on the "user ID" using a salt to convert the user ID into a hash value, and then the salt is discarded. As a result, de-identified data including the hash value "a12f7d9" corresponding to the "user ID" and the k-anonymized "target attribute information" is obtained.

[0025] Furthermore, the de-identification processing unit 11 of the device 10B of company B binarizes the target attribute information (step B3) and separates it into bit strings of the target attribute information (step B4). Here, to supplement the processing of steps B3 and B4 based on FIG. 4(b), in an example in which the de-identified data to be processed includes a "hash value" corresponding to the user ID and "visit information (1: yes, 0: no)" corresponding to the target attribute information as shown in the upper part of FIG. 4(b), the de-identification processing unit 11 binarizes the target attribute information according to the visit information (1: yes, 0: no). At this time, as shown in the middle part of FIG. 4(b), for example, the data of the hash value "4a3" has visit information, so it is converted to data in which the bit of "visit information present" is "1" and the bit of "no visit information" is "0", and the data of the hash value "3c0" does not have visit information, so it is converted to data in which the bit of "visit information present" is "0" and the bit of "no visit information" is "1". Then, the de-identification processing unit 11 separates the de-identified data for each bit sequence of the target attribute information (here, "10" or "01"), and as a result, as shown in the lower part of Figure 4(b), the data is separated into a group where the bit sequence of the target attribute information is "10" and a group where the bit sequence of the target attribute information is "01".

[0026] Next, the device 10A of company A and the device 10B of company B cooperate to encrypt the deidentified data as shown in FIG. 5 as follows.

[0027] In device 10A of company A, encryption unit 12 performs a first encryption on the deidentified data generated by deidentification processing unit 11 of device 10A based on the encryption key held by device 10A and the keyed one-way commutative operation (step A5 in FIG. 2; process (1A) in FIG. 5). Also, in device 10B of company B, encryption unit 12 performs a first encryption on the deidentified data generated by deidentification processing unit 11 of device 10B based on the encryption key held by device 10B and the keyed one-way commutative operation (step B5 in FIG. 2; process (1B) in FIG. 5). Then, the deidentified data after the first encryption is exchanged between devices 10A and 10B (steps A6 and B6 in FIG. 2; process (2) in FIG. 5). Since the de-identified data after the first encryption exchanged between devices 10A and 10B is encrypted based on the other device's encryption key that is not disclosed to the own device, the own device cannot decrypt the de-identified data and cannot recognize the contents of the de-identified data (personal information, etc.). Similarly, the other device cannot decrypt the de-identified data after the first encryption obtained by the exchange and cannot recognize the contents of the de-identified data (personal information, etc.).

[0028] Then, in the device 10A of company A, the encryption unit 12 performs a second encryption based on the encryption key held by the device 10A and the keyed one-way commutative operation on the deidentified data after the first encryption received from the device 10B of the other party, thereby generating doubly encrypted deidentified data after double encryption using the encryption key of the device 10A and the encryption key of the device 10B (step A7 in FIG. 2; process (3A) in FIG. 5). Also, in the device 10B of company B, the encryption unit 12 performs a second encryption based on the encryption key held by the device 10B and the keyed one-way commutative operation on the deidentified data after the first encryption received from the device 10A of the other party, thereby generating doubly encrypted deidentified data after double encryption using the encryption key of the device 10A and the encryption key of the device 10B (step B7 in FIG. 2; process (3B) in FIG. 5).

[0029] Furthermore, the encryption unit 12 of device 10B of company B transmits the double encrypted deidentified data obtained in step B7 to the encryption unit 12 of device 10A of company A (step B8; process (4) in Figure 5), and the encryption unit 12 of device 10A of company A receives the double encrypted deidentified data from device 10B of company B (step A8).

[0030] Here, the above encryption process will be explained in more detail with reference to FIG. 6. Let a be the data of company A and b be the data of company B. Let ka be the private key held by device 10A of company A and kb be the private key held by device 10B of company B. Let f be the process of encrypting x with private key k. k (x) (where f k (x is a keyed one-way commutative hash function), then the first encryption produces f ka (a) and f kb (b) is obtained, and these are exchanged between the devices 10A and 10B. Next, the second encryption is performed in the device 10A of the company A using the private key ka of the company A, resulting in f ka (f kb (b)) is obtained, and the second encryption is performed in the device 10B of company B using the private key kb of company B, and f kb (f ka (a)) is obtained. Then, f is sent from the device 10B of company B to the device 10A of company A. kb (f ka (a)) is sent.

[0031] As described above, the device 10A of company A and the device 10B of company B perform encryption twice in total without disclosing the secret keys ka and kb held by their own devices to the other device. k Since (x) is a keyed one-way commutative hash function, according to the properties of commutative hash functions, when a=b, f kb (f ka (a))=f ka (f kb (b)) is true.

[0032] Next, in the device 10A of company A, the tallying process for each combination of conditions is executed as shown in Fig. 7. That is, the tallying process unit 13 of the device 10A of company A compares the doubly encrypted de-identified data after the second encryption for each combination of conditions (step A9 in Fig. 2), and counts the number of data items with matching "user ID parts" specified based on the structural information of the user data shared in advance between the devices 10A and 10B, thereby tallying up the number of target users (step A10 in Fig. 2).

[0033] Here, the processing of steps A9 and A10 above will be supplementarily explained using an example in which the double encrypted de-identified data obtained by the processing of FIGS. 4(a) and 4(b) are compared with each other.

[0034] For the combination of conditions "used and visited" shown in Fig. 7(a), only data with hash value 4a3 was obtained (matchable) as data with a matching user ID (hash value) portion after double encryption, so the count value "1" of the number of data with a matching user ID portion after double encryption is obtained as the tally result. For the combination of conditions "used and not visited" shown in Fig. 7(b), only data with hash value 6f8 was obtained (matchable) as data with a matching user ID portion after double encryption, so the count value "1" of the number of data with a matching user ID portion after double encryption is obtained as the tally result.

[0035] Similarly, for the combination of conditions "no use and visit" shown in Figure 7(c), two pieces of data, data with hash value 1e5 and data with hash value 5d9, were obtained as data with matching user ID parts after double encryption (matching was possible), so the count value "2" of the number of pieces of data with matching user ID parts after double encryption is obtained as the tabulation result. For the combination of conditions "no use and no visit" shown in Figure 7(d), only data with hash value 3c0 was obtained as data with matching user ID parts after double encryption (matching was possible), so the count value "1" of the number of pieces of data with matching user ID parts after double encryption is obtained as the tabulation result.

[0036] Next, in the device 10A of company A, the anonymity processing unit 14 performs anonymity processing based on differential privacy on the tabulated results obtained in step A10, and generates and outputs statistical information from which correspondence with individuals has been excluded (step A11 in FIG. 2). To explain this using the tabulated results obtained in FIG. 7(a) to FIG. 7(d) as an example, the anonymity processing unit 14 performs anonymity processing based on differential privacy on the tabulated results for each of the four conditions of combinations of "with / without use" and "with / without visit" shown in FIG. 8, and generates and outputs statistical information for each of the four conditions from which correspondence with individuals has been excluded (n1, n2, n3, and n4 in the example of FIG. 8).

[0037] According to the embodiment of the present disclosure described above, by linking the device 10A of company A and the device 10B of company B, it is possible to generate statistical information that excludes correspondence with individuals, without disclosing to other devices either the personal information in the unencrypted user data held by each device or the encryption key of each device. In the above example, it is possible to generate statistical information for each of four conditions, which are combinations of "with / without use" of the service of company A and "with / without visit" to the store of company B, and it is possible to realize data linking between companies A and B while protecting privacy, and to obtain useful statistical information. Such useful statistical information can be effectively used for advertising measures, customer attraction measures, and the like for both companies A and B.

[0038] Furthermore, when the conditions that the personal information must satisfy in order to extract the target users include multiple conditions, the de-identification processing unit 11 generates de-identified data (grouped de-identified data) corresponding to a group of user data whose personal information satisfies each of the multiple conditions, thereby making it possible to obtain statistical information regarding the number of multiple target users who satisfy each of the multiple conditions.

[0039] Furthermore, the encryption unit 12 cooperates with the encryption unit 12 of the other device to execute the series of processes (first encryption → data exchange → second encryption) shown in Figures 5 and 6 described above, so that both device 10A of Company A and device 10B of Company B can execute a total of two encryptions without disclosing the private keys ka, kb held by their own devices to the other device, thereby generating doubly encrypted de-identified data after doubly encryption using the private keys ka, kb.

[0040] Moreover, the irreversible conversion process executed by the de-identification processor 11 includes a hashing process. Therefore, it is not necessary to apply a special irreversible conversion process, and it is possible to apply a general irreversible conversion process, namely a hashing process, thereby improving ease of implementation.

[0041] In addition, after executing the hashing process on the user ID, the de-identification processing unit 11 discards the salt used in the hashing process. By discarding the salt used in the hashing process in this way, it is possible to take every possible measure to eliminate the possibility of data restoration.

[0042] In addition, the privacy protection performed by the de-identification processing unit 11 includes at least one of k-anonymization, l-diversity, and t-closeness. Therefore, it is not necessary to apply special privacy protection, and general privacy protection such as k-anonymization, l-diversity, and t-closeness can be applied, improving ease of implementation.

[0043] In addition, the concealment processing executed by the concealment processing unit 14 includes a concealment processing based on differential privacy. Therefore, it is not necessary to apply a special concealment processing, and it is possible to apply a general concealment processing, that is, a concealment processing based on differential privacy, and it is possible to improve ease of implementation.

[0044] (About modified examples) The privacy protection data linkage system according to the present disclosure described above can employ the following first and second modified examples.

[0045] The first modified example is a form in which statistical information on the number of target users is generated by cooperation between a total of three devices, including a "first device", a "second device", and a "third device" among the multiple devices constituting the privacy protection data linking system. The second modified example is a form in which the privacy protection data linking system is composed of two types of devices, a plurality of encryption devices that perform up to the encryption process, and a counting device that performs the counting process and beyond. Each of the modified examples will be described in order below.

[0046] (First Modification) As shown in Fig. 9, the privacy protection data linkage system 1A according to the first modified example is a system that generates statistical information on the number of target users through linkage between a total of three devices, namely, "one device", "other device", and further, "third device". Fig. 9 shows an example in which the privacy protection data linkage system 1A is configured to include a plurality of devices 10A, 10B, and 10C. Note that, for convenience of explanation, Fig. 9 shows three devices 10A to 10C, but four or more devices may be provided.

[0047] In the first variant, an example will be described in which device 10A of company A operates as "one device", device 10B of company B operates as "other device", and device 10C of company C operates as "third device". Each device has the same functional block configuration, and may operate as "one device", "other device", or "third device".

[0048] The functions and effects of the "de-identification processing unit 11", "encryption unit 12", "counting processing unit 13" and "secrecy processing unit 14" of each device are similar to those described in the embodiment of the present disclosure, and therefore a duplicated description will be omitted here. Note that structural information of the user data held by each device is shared in advance between the devices, and based on the structural information, it is possible to identify the "user ID corresponding portion" in the double encrypted de-identified data generated in each of devices 10A and 10B described below, and it is possible to match the "user ID corresponding portion" between the double encrypted de-identified data described below.

[0049] FIG. 10 shows a series of processes executed in the privacy protection data linkage system 1A of the first modified example. Note that the same reference numerals are used for the processes similar to those in FIG. 2 described in the embodiment of the present disclosure above. In FIG. 10, the processes related to the generation of deidentified data executed by the deidentification processing unit 11 of the device 10A of company A (steps A1 to A4), the processes related to the encryption of deidentified data executed by the encryption unit 12 of the device 10A of company A (steps A5 to A8S), the processes related to the generation of deidentified data executed by the deidentification processing unit 11 of the device 10B of company B (steps B1 to B4), and the processes related to the encryption of deidentified data executed by the encryption unit 12 of the device 10B of company B (steps B5 to B8) are almost similar to the processes in FIG. 2 described above, and therefore repeated explanations will be omitted. However, in steps A8S and B8, the double encrypted deidentified data after the second encryption is transmitted to the device 10C of company C operating as the "third device".

[0050] The double encrypted deidentified data from each of the device 10A of the company A and the device 10B of the company B is received by the counting processing unit 13 of the device 10C of the company C (step C1). Thereafter, the counting processing unit 13 of the device 10C of the company C refers to the structural information of the user data shared in advance between the devices in the same manner as in step A9 of Fig. 2 described above, and compares the double encrypted deidentified data from the device 10A with the double encrypted deidentified data from the device 10B (step C2), and counts the number of data whose user ID parts match in the same manner as in step A10 of Fig. 2 described above, thereby counting the number of target users (step C3). Furthermore, the concealment processing unit 14 of the device 10C of the company C performs concealment processing based on differential privacy on the counting results obtained in step C3 in the same manner as in step A11 of Fig. 2 described above, generates statistical information in which the correspondence with individuals is excluded, and outputs it to each of the device 10A of the company A and the device 10B of the company B (step C4).

[0051] In the first modification as described above, by realizing mutual data linkage between the device 10A of company A, the device 10B of company B, and the device 10C of company C while protecting privacy, statistical information in which the correspondence with individuals is excluded can be generated without disclosing to other devices the personal information and encryption key in the unencrypted user data held by companies A and B. In this way, data linkage between companies A, B, and C can be realized while protecting privacy, and useful statistical information can be obtained. Such useful statistical information can be effectively used for advertising measures, customer attraction measures, and the like by both companies A and B who hold the user data.

[0052] (Second Modification) As shown in Fig. 11, the privacy protection data linkage system 1B according to the second modification is composed of two types of devices, namely, encryption devices 10X and 10Y which perform processes up to encryption, and a tallying device 10Z which performs processes after tallying, and is a system which generates statistical information on the number of target users through cooperation between a total of three devices, namely, the encryption devices 10X and 10Y and the tallying device 10Z. Note that, for convenience of explanation, Fig. 11 shows two encryption devices 10X and 10Y and one tallying device 10Z, but three or more encryption devices and two or more tallying devices may be provided.

[0053] The second variant is similar to the first variant described above in that statistical information regarding the number of target users is generated through cooperation between a total of three devices, but differs in that there are two types of devices: an encryption device that specializes in performing processes up to the encryption process, and a counting device that specializes in performing processes from the counting process onwards.

[0054] Therefore, as shown in Fig. 11, each of the encryption devices 10X and 10Y includes a "de-identification processing unit 11" and an "encryption unit 12" among the components of each device shown in Fig. 1 and Fig. 9, and the tallying device 10Z includes a "tallying processing unit 13" and a "secrecy processing unit 14" among the components of each device shown in Fig. 1 and Fig. 9. The functions and effects of each of these components are similar to those described in the embodiment of the present disclosure, and therefore repeated description will be omitted here.

[0055] Fig. 12 shows a series of processes executed in the privacy protection data linkage system 1B of the second modified example, and the same processes as those in Fig. 10 described in the first modified example above are given the same reference numerals. As is clear from comparing Fig. 12 with Fig. 10, the series of processes in steps A1 to A8S, B1 to B8, and C1 to C4 are the same as those in Fig. 10.

[0056] Therefore, the deidentification processing unit 11 and the encryption unit 12 of the encryption device 10X in Fig. 11 respectively perform the same operations as the deidentification processing unit 11 and the encryption unit 12 of the device 10A of company A in Fig. 9, and the deidentification processing unit 11 and the encryption unit 12 of the encryption device 10Y in Fig. 11 respectively perform the same operations as the deidentification processing unit 11 and the encryption unit 12 of the device 10A of company B in Fig. 9. At this time, the double encrypted deidentified data generated by a total of two encryptions while protecting privacy in each of the encryption devices 10X and 10Y is received by the counting processing unit 13 of the counting device 10Z (step C1 in Fig. 12), and the counting processing unit 13 and the concealment processing unit 14 of the counting device 10Z respectively perform the same operations as the counting processing unit 13 and the concealment processing unit 14 of the device 10C of company C in Fig. 9. As a result, a confidentiality process based on differential privacy is performed on the aggregated results obtained in step C3 of FIG. 12, and statistical information that excludes correspondence with individuals is generated and output to each of the encryption devices 10X and 10Y.

[0057] In the second modification as described above, by realizing mutual data linkage between the encryption devices 10X and 10Y and the counting device 10Z while protecting privacy, statistical information in which the correspondence with individuals is excluded can be generated without disclosing to other devices the personal information and the encryption key in the unencrypted user data held by the encryption devices 10X and 10Y. In this way, data linkage between the encryption devices 10X and 10Y and the counting device 10Z can be realized while protecting privacy, and useful statistical information can be obtained. Such useful statistical information can be effectively used for advertising measures, customer attraction measures, etc. for both the organization holding the encryption device 10X and the organization holding the encryption device 10Y.

[0058] (Explanation of terms, explanation of hardware configuration (Fig. 13), etc.) The block diagrams used to explain the above embodiments and modifications show functional blocks. These functional blocks (components) are realized by any combination of at least one of hardware and software. The method of realizing each functional block is not particularly limited. That is, each functional block may be realized by using one device that is physically or logically combined, or may be realized by using two or more devices that are physically or logically separated and directly or indirectly connected (for example, by wire, wirelessly, etc.). The functional blocks may be realized by combining the one device or the multiple devices with software.

[0059] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs the function of transmission is called a transmitting unit or a transmitter. As described above, there is no particular limitation on the method of realization of each of these.

[0060] For example, an apparatus according to an embodiment of the present disclosure may function as a computer that performs the processing according to this embodiment. Fig. 13 is a diagram showing an example of a hardware configuration of an apparatus 10 according to an embodiment of the present disclosure. The apparatus 10 collectively refers to the above-mentioned apparatuses 10A to 10C, the encryption apparatuses 10X and 10Y, and the tallying apparatus 10Z. The above-mentioned apparatus 10 may be physically configured as a computer apparatus including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, and the like.

[0061] In the following description, the term "apparatus" may be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus 10 may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0062] Each function of the device 10 is realized by loading a specific software (program) onto hardware such as a processor 1001 and a memory 1002, causing the processor 1001 to perform calculations, control communication by a communication device 1004, and control at least one of reading and writing of data in the memory 1002 and the storage 1003.

[0063] The processor 1001 controls the entire computer by running, for example, an operating system. The processor 1001 may be configured with a central processing unit (CPU) including an interface with peripheral devices, a control device, an arithmetic unit, a register, and the like.

[0064] Furthermore, the processor 1001 reads out programs (program codes), software modules, data, etc. from at least one of the storage 1003 and the communication device 1004 into the memory 1002, and executes various processes according to these. As the programs, those that cause a computer to execute at least a part of the operations described in the above-mentioned embodiments are used. Although the above-mentioned various processes have been described as being executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0065] The memory 1002 is a computer-readable recording medium, and may be configured by at least one of, for example, a Read Only Memory (ROM), an Erasable Programmable ROM (EPROM), an Electrically Erasable Programmable ROM (EEPROM), a Random Access Memory (RAM), etc. The memory 1002 may be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 can store a program (program code), software modules, etc. that are executable to implement a wireless communication method according to an embodiment of the present disclosure.

[0066] Storage 1003 is a computer-readable recording medium, and may be composed of at least one of, for example, an optical disk such as a CD-ROM (Compact Disc ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray (registered trademark) disk), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy (registered trademark) disk, a magnetic strip, and the like. Storage 1003 may be referred to as an auxiliary storage device. The above-mentioned storage medium may be, for example, a database including at least one of memory 1002 and storage 1003, or other suitable medium.

[0067] The communication device 1004 is hardware (transmission / reception device) for performing communication between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0068] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that accepts input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that performs output to the outside. The input device 1005 and the output device 1006 may be integrated (e.g., a touch panel). Each device such as the processor 1001 and the memory 1002 is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0069] Each aspect / embodiment described in this disclosure may be used alone, in combination, or switched according to execution. In addition, notification of specific information (e.g., notification that "X is the case") is not limited to being done explicitly, but may be done implicitly (e.g., not notifying the specific information).

[0070] Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be implemented in modified and altered forms without departing from the spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0071] The order of the steps, sequences, flow charts, etc. of each aspect / embodiment described in this disclosure may be changed unless inconsistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0072] The input and output information may be stored in a specific location (e.g., memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0073] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0074] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Further, when used in this disclosure, the term "or" is not intended to be an exclusive or.

[0075] In this disclosure, where articles have been added due to translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0076] In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "coupled" may also be interpreted in the same way as "different." [Explanation of symbols]

[0077] 1, 1A, 1B... privacy protection data linkage system, 10, 10A, 10B, 10C... device, 10X, 10Y... encryption device, 10Z... aggregation device, 11... de-identification processing unit, 12... encryption unit, 13... aggregation processing unit, 14... confidentiality processing unit, 1001... processor, 1002... memory, 1003... storage, 1004... communication device, 1005... input device, 1006... output device, 1007... bus.

Claims

1. A plurality of devices are provided for storing user data including user IDs and personal information relating to users, Each of the devices comprises: a de-identification processing unit that de-identifies the user data to generate de-identified data; an encryption unit that performs a first encryption process on the de-identified data using its own encryption key held by its own device, and a second encryption process on the de-identified data that has been first encrypted and received from the other device using its own encryption key; a counting processing unit that compares the second encrypted de-identified data with the second encrypted de-identified data received from the other device, and counts the number of second encrypted de-identified data that match a portion corresponding to a user ID specified based on predetermined structural information of the user data as the number of target users; Including, Privacy-preserving data linkage system.

2. A plurality of devices are provided for storing user data including user IDs and personal information relating to users, Each of the devices comprises: a de-identification processing unit that de-identifies the user data to generate de-identified data; an encryption unit that performs a first encryption process on the de-identified data using a first encryption key held by a first device, and performs a second encryption process on the de-identified data that has been first encrypted and received from a second device using the first encryption key; a third device, a counting processing unit that compares the second encrypted de-identified data of the first device with the second encrypted de-identified data of the second device, and counts the number of second encrypted de-identified data in which a portion corresponding to a user ID specified based on predetermined structural information of the user data matches as the number of target users; Including, Privacy-preserving data linkage system.

3. The system includes a plurality of encryption devices for holding and encrypting user data including a user ID and personal information related to the user, and a counting device; Each of the encryption devices comprises: a de-identification processing unit that de-identifies the user data to generate de-identified data; an encryption unit that performs a first encryption process on the de-identified data using its own encryption key held by its own device, and a second encryption process on the de-identified data that has been first encrypted and received from the other device using its own encryption key; Including, The counting device is a counting processing unit that compares the second encrypted de-identified data received from the encryption device with the second encrypted de-identified data received from a device other than the encryption device, and counts the number of second encrypted de-identified data in which a portion corresponding to a user ID specified based on predetermined structural information of the user data matches as the number of target users; Including, Privacy-preserving data linkage system.

4. the de-identification processing unit extracts the user data based on a condition that the personal information should satisfy, and generates de-identified data corresponding to the extracted user data. The privacy protection data linkage system according to any one of claims 1 to 3.

5. When the conditions to be satisfied by the personal information include a plurality of conditions, the de-identification processing unit generates grouped de-identified data corresponding to groups of user data in which the personal information satisfies each of the plurality of conditions. The privacy-preserving data linkage system according to claim 4.

6. The de-identification processing unit further performs processing for privacy protection of the personal information. A privacy protection data linkage system according to any one of claims 1 to 5.

7. Each of the devices comprises: a concealment processing unit that performs concealment processing on the tally results obtained by the tally processing unit to generate concealed statistical information; The privacy-preserving data linking system according to claim 1 or 2, further comprising:

8. The counting device is a concealment processing unit that performs concealment processing on the tally results obtained by the tally processing unit to generate concealed statistical information; The privacy-preserving data linkage system of claim 3 , further comprising:

9. a de-identification processing unit that de-identifies user data including at least a user ID to generate de-identified data; an encryption unit that performs a first encryption process on the de-identified data using its own encryption key held by its own device, and a second encryption process on the de-identified data that has been first encrypted and received from the other device using its own encryption key; a counting processing unit that compares the second encrypted de-identified data with the second encrypted de-identified data received from the other device, and counts the number of second encrypted de-identified data that match a portion corresponding to a user ID specified based on predetermined structural information of the user data as the number of target users; Including, Privacy-preserving data linkage device.

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