JP4700408B2 - Unauthorized outflow detection system, unauthorized outflow detection server, and unauthorized outflow detection program - Google Patents

Description

  The present invention relates to a fraudulent outflow detection system, a fraudulent outflow detection server, and a fraudulent outflow detection program, and in particular, fraudulent outflow detection for realizing with high accuracy the identification of an access right person involved in illegal outflow of a database. The present invention relates to a system, an unauthorized outflow detection server, and an unauthorized outflow detection program.

  In recent years, provision of contents such as images, videos, and music using a communication network such as an intranet has become widespread. Here, when content is transmitted to an access right holder terminal used by the access right holder via a communication network, a technique such as encryption is used to prevent unauthorized eavesdropping or leakage.

Further, recently, when content is illegally distributed, a technique for adding a predetermined digital watermark at the time of providing content is used to specify the secondary distributor (see, for example, Patent Document 1). .) As disclosed in Patent Document 1, by distributing contents embedded with unique watermark information to each user, if any illegal secondary distribution of content is found, which use It can be specified whether the secondary distribution was made by the person.
JP 2002-359835 A

However, the above-described method has a limited range of application to image data, audio data, moving image data, etc. For example, a collection of characters, numerical values, figures, and other information such as a customer information database and an employee database is systematic. It cannot be used for databases configured in Further, in the prior art, it is difficult to identify a leaker of an unauthorized leaker of a database unless an administrator or the like acquires leaked data itself.

  The present invention has been made in view of the above-described problems, and an unauthorized outflow detection system, an unauthorized outflow detection server, and an unauthorized outflow for realizing with high accuracy the identification of an access right person involved in unauthorized outflow of a database. It is an object to provide a person detection program.

  In order to solve the above problems, the present invention employs means for solving the problems having the following characteristics.

The invention described in claim 1 specifies an access right person who has been involved in illegal outflow when an access right person terminal used by the access right person and a database provided to the access right person terminal are illegally leaked. In the fraudulent outflow detection system comprising the fraudulent outflow detection server, the fraudulent outflow detection server uses a c-secure code to assign different code words for each access right person, A dummy entry managing means for generating a dummy entry different from a database entry based on the length of the code word obtained by the code word assigning means, and managing the generated dummy entry in association with the code word ; The dummy entry management means stores a dummy entry that is managed in association with the codeword. A me database and at least one dummy entry corresponding to the code word assigned to the access right holder by the code word assigning means is extracted from the dummy database, and the extracted dummy entry is stored in the access right holder terminal. a data generation unit to insert the database to provide, to generate a extract the dummy entries included in the unauthorized outflow database, allocated from the extracted dummy entry for each of the access owner said codeword And an access right person specifying means for specifying an access right person corresponding to the code word .

According to the first aspect of the present invention, it is possible to quickly and accurately identify the access right owner who has been involved in the illegal outflow of the database using the dummy entry. In addition, a unique dummy entry can be assigned to each access right holder.

The invention described in claim 2 is a fraudulent outflow detection server for identifying an access right holder who has been involved in illegal outflow when a database provided to an access right terminal used by an access right holder is illegally leaked. A codeword allocating means for allocating different codewords for each access right person using a c-secure code, and a length of the codeword obtained by the codeword allocating means for a dummy entry different from an actual database entry And a dummy entry management means for managing the generated dummy entry in association with the codeword, and a dummy for storing dummy entries managed in association with the codeword by the dummy entry management means A database and the code assigned to the access right holder by the codeword assigning means Extracting at least one dummy entries corresponding to words from the dummy database, a data generation unit to insert the database that provides the extracted dummy entry in the access terminal, included in the illegally outflow database the extracts dummy entries that, the extracted to generate the code word assigned to each of the access person from the dummy entries, and access rights user identification means for identifying an access right holder corresponding to the codeword It is characterized by having.

According to the second aspect of the present invention, it is possible to quickly and highly accurately identify the access right person who is involved in the illegal outflow of the database using the dummy entry. In addition, a unique dummy entry can be assigned to each access right holder.

The invention described in claim 3, wherein the access user identification means, said generating a code word from a set of dummy entries, the bit string of the generated code words, a code word using the c-secure code The access right holder is specified by comparing with a bit string.

According to the third aspect of the present invention, the access right holder can be specified with high accuracy based on the bit string.

The invention described in claim 4 is characterized in that the access right person specifying means specifies an access right person based on an e-mail distributed to a mail address included in the dummy entry.

According to the invention described in claim 4, when it is not necessary to track a database that has been illegally leaked and an e-mail or the like is delivered using an e-mail address included in the database, the access right is determined from the destination information. Person can be identified.

The invention described in claim 5, wherein the code word assigning means, in the c-secure code, and characterized in that the frequency of occurrence of the Hamming weight of the inner code is small code words constituting the outer code to be greater To do.

According to the fifth aspect of the present invention, it is possible to reduce the hamming weight of the entire c-secure code by increasing the appearance frequency of the code word having a small hamming weight in the outer code.

The invention described in claim 6 is an unauthorized outflow detection program that causes a computer to function as the unauthorized outflow detection server according to any one of claims 2 to 5 .

According to the sixth aspect of the present invention, it is possible to quickly and highly accurately identify the access right person who has been involved in the illegal outflow of the database using the dummy entry. In addition, a unique dummy entry can be assigned to each access right holder. In addition, the illegal outflow detection process can be realized at low cost. Further, by installing the program, it is possible to easily realize the illegal outflow detection process.

  ADVANTAGE OF THE INVENTION According to this invention, the identification of the access right person who was involved in the illegal leak of a database is realizable with high precision.

  DESCRIPTION OF EMBODIMENTS Embodiments of an unauthorized outflow detection system, an unauthorized outflow detection server, and an unauthorized outflow detection program having features of the present invention will be described below in detail with reference to the drawings.

<Unauthorized outflow detection system>
FIG. 1 is a diagram illustrating a schematic configuration example of an unauthorized outflow detection system. An unauthorized outflow detection system 10 illustrated in FIG. 1 includes an unauthorized outflow detection server 11 and access right person terminals 12-1 to 12-n. 12 is connected in a state where data can be transmitted and received by a communication network 13 typified by, for example, an intranet. The communication network 13 may be wired or wireless.

  The unauthorized leaker detection server 11 is connected to a database (DB) 14, and in response to a database provision request from each access right user terminal 12-1 to 12-n, a predetermined database based on the access authority is DB 14. This is a providing server that is extracted and provided to the requested access right user terminal 12. Therefore, the unauthorized leaker detection server 11 stores the user authentication information (user ID, password, name, address, telephone number, FAX number, etc.) for access from each access right owner terminal 12-1 to 12-n and the DB 14. Access authority and the like for the stored data are set and managed in advance by a user registration process or the like.

  Further, when the unauthorized leaker detection server 11 provides the requested database to the access right owner terminal 12, the unique information (dummy entry) that is different for each access right holder is inserted into the database. As a result, if the provided database is leaked and a copy of the database is found or the email address stored in the database is used for, for example, distribution of spam emails, it differs for each access right person mentioned above Based on the unique information, it is possible to identify the access right person who was involved in the unauthorized leak.

  Here, the dummy entry in the present invention is dummy data generated on the server side, and is a record including data corresponding to each item of the database stored in the DB 14. In addition, in order to insert a different dummy entry for each access right holder, in the present invention, a c-secure code is used. (For the c-secure code, for example, “Don Boneh and James Shaw,“ Collection-secure Fingerprinting for Digital ” Data ", Advances in Cryptology-CRYPTO 1995, Lecture Notes in Computer Science 963, Springer-Verlag, pp 452-465, 1995.).

  Specifically, the unauthorized leaker detection server 11 assigns an individual codeword in the c-secure code to each access right holder. A dummy entry corresponding to the number of bits of the c-secure code is prepared in advance, and these are associated with each bit of the code word.

  Here, when there is a database provision request from each access right user terminal 12-1 to 12-n, the unauthorized leaker detection server 11 extracts a predetermined database based on the access authority from the DB 14, and the database ( A dummy entry corresponding to a bit position to which a predetermined value (for example, “1”) is given in a bit string of codewords assigned to each access right holder is inserted into an actual database. Thereby, a different dummy entry for each access right holder can be inserted into the actual database.

  Also, if the information in the provided database is leaked, the dummy entries inserted in this database are extracted, the code word of the bit string is restored from the set of these dummy entries, and it becomes the source of the leak Identify who has access.

  Further, the unauthorized leaked person detection server 11 uses a spam mail distributed to a mail address included in a dummy entry when a spam mail or the like is distributed using a mail address stored in a database by a third party or the like. The code word of the bit string is restored, and the access right person who is the source of the beta base leak is specified. A specific method for specifying the access right holder using the dummy entry will be described later.

  Further, each access right user terminal 12-1 to 12-n is a terminal used by a user having access right, and is stored in the DB 14 via the unauthorized outflow detection server 11 based on the access right for each user. Information can be acquired. In this embodiment, in order to explain specific functions of the unauthorized leaker detection server 11, for example, any access right holder (for example, the access right holder 12-2) collaborates with another unauthorized user. In the following description, the database stored in the DB 14 is illegally leaked.

  The DB 14 is a variety of information databases (contents) in which a collection of characters, numerical values, graphics, and other information is systematically configured. In the present embodiment, a customer information database is used as an example. Each entry (database record) is configured in the customer information database by the customer's name, e-mail address, address, and the like.

  Here, the system configuration shown in FIG. 1 is configured to have a plurality of (n) access right owner terminals 12-1 to 12-n for one unauthorized outflow detection server 11. The system configuration is not limited to this. For example, the relationship between the unauthorized leaker detection server 11 and the access right holder terminal 12 may be n-to-n, or may be one-to-one or n-to-one. . Further, the DB 14 may be provided in the unauthorized leaker detection server 11 or may be connected to the unauthorized leaker detection server 11 via the communication network 13 in a state where data can be transmitted and received.

  Next, a functional configuration example of the unauthorized outflow detection server 11 in the above-described embodiment will be described with reference to the drawings.

<Unauthorized Outflow Detection Server 11>
FIG. 2 is a diagram illustrating an example of a functional configuration of the unauthorized outflow detection server in the present embodiment. The unauthorized outflow detection server 11 in FIG. 2 includes a user management means 21, a code word generation means 22, a code word allocation means 23, a dummy entry management means 24, a data generation means 25, and an unauthorized outflow identification means 26. And a transmission / reception means 27.

  The user management unit 21 manages new registration, change, and update setting contents of each user's access right for each database or data stored in the DB 14. The user management unit 21 may manage a user ID, a password, and the like necessary for user authentication when accessing from the access right terminal 12 and also manage access from the access right terminal 12. .

  As described above, the codeword generation unit 22 generates a unique codeword for each access right person who has accessed by the access right person terminal 12 using, for example, a c-secure code. The code word may be generated so as to increase the code length in response to the increase in the number of registered access rights holders, or a predetermined code length corresponding to the preset maximum user registration number. It may be generated. Details of the codeword generation method will be described later. The codeword assigning unit 23 assigns the codeword generated by the codeword generating unit 22 to each access right person managed by the user managing unit 21.

  The dummy entry management means 24 manages a dummy database (dummy DB) 28 in which preset dummy information is stored. The dummy DB 28 has a dummy database having data items corresponding to various databases stored in the DB 14. The dummy entry management unit 24 generates a dummy entry corresponding to each bit of the codeword generated by the codeword generation unit 22. For example, when the code length of a codeword using a c-secure code is “L”, L dummy entries are generated and stored in the dummy DB 28. The dummy entry management means 24 performs management by associating each dummy entry with each bit of the code word.

  Further, the data generation means 25, based on the database provision request from the access right terminal 12 received by the transmission / reception means 27, provides a database that can be provided based on the authority of the access right person from the DB 14 in which the actual database is stored. Extract. Further, the data generation means 25 extracts a dummy entry corresponding to the code word assigned to each access right holder by the code word assignment means 23 from the dummy DB 28, and inserts the set of dummy entries into the extracted database. Generate a database containing dummy data. The data generation unit 25 can also manage the update and deletion of data stored in the DB 14.

  Further, the unauthorized leaker specifying means 26 extracts dummy entries included in the illegally leaked database, generates a code word from the set of the extracted dummy entries, and specifies an access right holder corresponding to the code word. To do. As a result, it is possible to quickly and accurately identify the access right person who is involved in the unauthorized leakage of the database. Further, for example, even when the access right holder terminal 12 is infected with a computer virus or the like and the database is illegally leaked without being recognized by the access right holder, the access right holder is identified and It is possible to quickly respond to the access right holder. In this case, the unauthorized leaker specifying means 26 generates a message indicating that an unauthorized leak has occurred to the specified access right holder, and transmits it to the access right holder terminal 12 from the transmission / reception means 27. Notification (warning) can also be performed. Thereby, further expansion of illegal outflow can be prevented.

  Further, when the unauthorized user is distributed spam mail using the email address included in the data entry, the unauthorized leaker identifying means 26 identifies the dummy entry included in the dummy DB 28 from the email address. A code word is generated from the set of dummy entries, and an access right person corresponding to the code word is specified. The details of the unauthorized outflower identifying method in the unauthorized outflower identifying means 26 will be described later.

  The transmission / reception means 27 receives the database provision request from the access right holder terminals 12-1 to 12-n. Further, the transmission / reception means 27 transmits the database generated by the data generation means 25 to the access right person terminal 12 that has made the provision request. The transmission / reception means 27 can also receive an electronic mail. That is, when the dummy entry includes a mail address, the transmission / reception means 27 can receive spam mail or the like distributed by the unauthorized user to the mail address.

<Example database>
Here, an example of a database stored in the DB 14 and the dummy DB 28 will be described with reference to the drawings. FIG. 3 is a diagram illustrating an example of a database in the present embodiment. FIG. 3A shows an example of an actual database stored in the DB 14, and FIG. 3B shows an example of dummy entries stored in the dummy DB 28.

  As shown in FIGS. 3A and 3B, each database item includes “name”, “mail address”, “address”, and the like. That is, the items included in the dummy entry correspond to various data items stored in the DB 14.

  In FIG. 3, for convenience, the dummy entry and the database entry are easily distinguished from each other. However, in reality, it is not possible to specify that the entry is a dummy entry even when the data is viewed by a person other than the administrator. Such data is accumulated. In addition to the “name”, “mail address”, and “address” described above, personal information such as “telephone number” and “FAX number” is also stored in the database.

<Codeword generation method>
Next, a code word generation method in the code word generation means 22 will be described. FIG. 4 is a diagram illustrating an example of a c-secure code in the present embodiment. In the example of FIG. 4, the correspondence between the dummy entries 1, 2,... And the code words w _{1 to} w _i is shown, and different sets of dummy entries are assigned to the code words w _{1 to} w _i , respectively. Yes.

The codeword generation means 22 arbitrarily selects a c-secure code composed of n codewords and assigns a different codeword to each access right holder. For _{example, w} 1, _w 2 a code word in the c-secure codes,..., And _{w n,} the access right person _u 1, _{u 2,} ..., When _{u n,} access holders _{u i} to a code word w _i is assigned.

Accordingly, as shown in FIG. 4, for example, in the case of the access right person u ₁ , the code word w ₁ is assigned, so the dummy 1,... Is extracted, and in the case of the access right person u ₂ , the code word w ₂ is Since it is assigned, dummy 1, dummy 3,... Are extracted, and the set of extracted dummy entries is inserted into the actual database.

<Database generation method>
Next, a method for generating a database provided to the access right holder will be described. First, the dummy entry generation unit 24 generates a dummy entry corresponding to the length (code length) of a code word using a c-secure code. As described above, for example, when the code length of the c-secure code is “L”, L dummy entries are generated. Here, let L dummy entries be e ₁ , e ₂ ,..., E _L.

Next, it is assumed that an access right user u _i makes a database provision request. The data generation unit 25 refers to the c-secure code of the code word (for example, w _i ) corresponding to the access right user u _i , and refers to the bit in which “1” is set in the code bit string. Here, it is assumed that the value of the j-th bit of I _i = {jε {1,..., L} | w _i is “1”}. At this time, the data generation means 25 extracts a set of corresponding dummy entries {e _j | jεI _i } from the dummy DB 28.

Next, the data generation means 25 extracts an actual database corresponding to the authority of the access right user u _i from the DB 14, and inserts a set of dummy entries {e _j | j∈I _i } into the extracted actual database. Database DB _i is generated. The data generation means 25 provides the generated DB _i to the access right user u _i . According to the above-described method, the data amount of DB _i depends on the Hamming weight, not the code length of the c-secure code.

  Here, FIG. 5 is a diagram showing an example of a database provided to the access right holder in the present embodiment. In the database shown in FIG. 5, the “dummy 2” entry is inserted into the actual database entry at a predetermined position set by a random number or the like. As a result, it is possible to make it difficult for a person other than the administrator to extract all dummy entries from the actual entries.

  In addition, as described above, since the contents of the set of dummy entries inserted for each access right holder are unique to each access right holder, even if multiple access right holders collide, It is difficult to extract all dummy entries.

<Illegal outflow identification method>
Here, a method for identifying an unauthorized outflow when a database including dummy entries as shown in FIG. 5 is leaked will be described.

  For example, it is assumed that an unauthorized access right person leaks a database DB ′ including a dummy entry due to collusion by a plurality of persons. Here, when the illegally leaked DB ′ is acquired, the unauthorized leaker specifying unit 26 extracts a dummy entry from the data group included in the DB ′. As a method for extracting a dummy entry, for example, it can be easily extracted by comparing with a dummy entry stored in the dummy DB 28.

  Further, when the spam address is distributed using the mail address included in the DB ′ obtained by the unauthorized user, the mail sent to the dummy entry mail address is received by the transmission / reception means 27. Further, the unauthorized leaker specifying means 26 extracts a corresponding dummy entry by referring to the dummy DB 28 from the destination mail address described in the mail.

  The e-mail address set in the dummy entry does not have to be an e-mail address that can be received by the unauthorized leaker detection server 11. For example, a plurality of e-mail transmission / reception terminals or e-mail servers are installed on the communication network 13. These mail addresses may be set as dummy entry mail addresses, and when spam mail is received by the terminal or server, the mail address may be forwarded to the unauthorized leaker detection server 11.

Next, the fraudulent outflower identifying means 26 sets the set of dummy entries extracted by the above-described method as I′⊂ {e ₁ , e ₂ ,..., E _L }, and uses, for example, the following expression (1) The codeword w ′ = (b ₁ || b ₂ ||... || b _L ) is generated based on the above condition.

最後に、不正流出者特定手段２６は、符号語ｗ’をｃ−ｓｅｃｕｒｅ符号の追跡アルゴリズムに入力し、これによって出力されたアクセス権者をＤＢ’の漏洩に関与したアクセス権者として検出する。

Finally, the unauthorized outflower identifying means 26 inputs the code word w ′ to the c-secure code tracking algorithm, and detects the access right person outputted as an access right person involved in the leakage of DB ′.

  Here, the tracking algorithm of the c-secure code will be described. First, a technique for flexibly adjusting the Hamming weight in the c-secure code as shown in FIG. 4 described above will be described. Here, as an example, the number of code words is n = 6, and the inner code at this time is configured as shown in the following equation (2).

ここで、符号語ｗ^〜 _１〜ｗ^〜 _４の長さ（符号長）は、それぞれ３Ｄビットとする。また、外符号は以下に示す（３）式のように構成する。

Here, the length of the code word ^w _~ 1 ^~w _{~ 4} (code length), respectively the 3D bit. Further, the outer code is configured as shown in the following equation (3).

上述した条件において、以下に示すようにｗ’からＤＢ’の漏洩に関与したアクセス権者の追跡を行う。

Under the conditions described above, the access right person who is involved in the leakage of DB ′ from w ′ is traced as shown below.

Now, the code word w '= (w ~ a' || w ~ b '|| w ~ c' || w ~ d '|| w ~ e') and defined. Here, w ~ if there is "1" somewhere D bits at the head of a ', it w ~ that described above (2) "1" at the beginning of the D bit in is set 1 because there is only, replace the w ~ a 'to w ~ 1. Also, w ~ a 'when there is a significant bias in the distribution of the D bit and the next D bit of the first of the "0""1", w ~ a' replace the w ~ 2. Also, w ~ a 'when there is a last D-bit and significant deviation in the distribution of the in the D bit of the immediately preceding "0" and "1" of, w ~ a' replace the w ~ 3, w ~ 'If the case there is a "0" somewhere in the last of the D-bit, w ~ a' a replace to w ~ 4.

Next, w ^to _b ′, w ^to _c ′, w ^to _d ′, and w ^to _e ′ are also replaced with any of w ^to ₁ ^to w ^to _{4 in} the same manner as in the case of w ^to _a ′ described above. After performing such processing, a code word that is most similar to w ′ is extracted from w ₁ to w ₆ shown in the above-described equation (3). Also, if the extracted code word is w _i , it can be seen that the access right person u _i corresponding to the code word w _i is most likely an access right person involved in the unauthorized leakage of DB ′, Access rights are identified.

As described above, by using the c-secure code in the present invention, it is possible to adjust the Hamming weight by adjusting only the outer code without modifying the inner code. More specifically, the inner code and the outer code are usually designed independently of each other. However, due to system limitations, it may be necessary to design the outer code according to the system requirements once the inner code is determined. For example, in the content described in the above-mentioned document “Collation-secure Fingerprinting for Digital Data”, the outer code is designed so that the appearance frequency of each codeword becomes equal. However, in the present invention, the case where the appearance frequency of each code word is non-uniform is allowed, and in particular, the appearance frequency of a code word (for example, w ₄ ^{to in} Equation (2)) with a small Hamming weight of the outer code is reduced. By increasing it, it is possible to reduce the Hamming weight of the entire c-secure code. Further, as described above, the Hamming weight can be adjusted by adjusting only the outer code without modifying the inner code.

  Accordingly, in the present invention, the amount of data in the database provided to the access right holder depends on the Hamming weight, and therefore the amount of data to be provided can be reduced. As described above, the unauthorized leaker detection server 11 according to the present invention can identify the access right person involved in the unauthorized leak with high accuracy.

  Here, the unauthorized leaker detection server 11 according to the present invention can perform the unauthorized leaker detection process according to the present invention using the above-described dedicated device configuration, etc., but it is possible to cause a computer to execute the process in each configuration. By generating an executable execution program and installing the program in, for example, a general-purpose personal computer, workstation, or the like, the unauthorized outflow detection process in the present invention can be realized.

<Hardware configuration>
Here, an example of a hardware configuration of a computer capable of executing the illegal outflow detection process according to the present invention will be described with reference to the drawings. FIG. 6 is a diagram illustrating an example of a hardware configuration capable of realizing the unauthorized outflow detection process according to the present invention.

  6 includes an input device 31, an output device 32, a drive device 33, an auxiliary storage device 34, a memory device 35, a CPU (Central Processing Unit) 36 for performing various controls, and a network connection device. 37, and these are connected to each other by a system bus B.

  The input device 31 has a pointing device such as a keyboard and a mouse operated by a user who uses a computer, and inputs various operation signals such as execution of a program from the user. The output device 32 has a display (monitor) for displaying various windows and data necessary for operating the computer main body for performing the processing in the present invention. Execution progress and results can be displayed.

  Here, in the present invention, the execution program installed in the computer main body is provided by, for example, the recording medium 38 such as a CD-ROM. The recording medium 38 on which the program is recorded can be set in the drive device 33, and the execution program included in the recording medium 38 is installed in the auxiliary storage device 34 from the recording medium 38 via the drive device 33.

  The auxiliary storage device 34 is a storage means such as a hard disk, and can store an execution program according to the present invention, a control program provided in a computer, the above-described dummy DB 28, and the like, and can perform input / output as necessary.

  Based on a control program such as an OS (Operating System) and an execution program read and stored by the memory device 35, the CPU 36 performs various operations and inputs / outputs data to / from each hardware component. Each process in the unauthorized outflow detection program can be realized by controlling the process. Various information necessary during the execution of the program can be acquired from the auxiliary storage device 34 and can be stored.

  The network connection device 37 acquires an execution program from another terminal connected to the communication network by connecting to a communication network or the like, or an execution result obtained by executing the program or an execution in the present invention The program can be provided to other terminals.

  With the hardware configuration as described above, a special device configuration is not required, and unauthorized outflow detection processing can be realized at low cost. Further, by installing the program, it is possible to easily realize the illegal outflow detection process. Next, an unauthorized outflow detection process procedure in the unauthorized outflow detection program will be described with reference to a flowchart. In addition, as an illegal leaked person detection processing procedure, a process for providing data to an access right holder and a process for acquiring the illegal leaked data and identifying the access right person involved in the illegal leak will be described separately.

<Unauthorized Outflow Detection Processing Procedure: Database Provision Processing>
FIG. 7 is a flowchart illustrating an example of a database providing process procedure in the unauthorized outflow detection process. In the database providing process procedure shown in FIG. 7, a part for performing user registration for access from a new user will also be described. However, the following processes of S01 to S03 are performed for an already registered access authority. I will not.

  First, user registration is performed in response to a user registration request from a user (S01). In addition, as user registration, when performing user authentication at the time of access, user ID, a password, a name, etc. are registered, and also the access authority to the database provided to each user is set. Also, codewords are assigned to the new user (access rights holder) set in S01 (S02). Further, when the code length of the code word is increased by the process in S02, a new data entry is generated (S03). This is done depending on the number of codewords increasing due to the combination of codewords in the c-secure code.

  Next, when a provision request for a database stored in advance is received from the access right holder terminal (S04), user authentication of the access right holder is performed, and the actual data is configured based on the access right corresponding to the access right holder. The actual database to be extracted is extracted (S05). Also, a dummy entry set having at least one dummy entry corresponding to the access right holder is extracted (S06). At this time, from the dummy entry set, for example, as described above, a dummy entry associated with the code word of the c-secure code is extracted.

  Next, the dummy entry set extracted in S06 is inserted into the actual database extracted in S05 (S07), and a database including dummy entries is provided to the requested access right terminal (S08).

  Thereby, the dummy entry which is information peculiar to every access right holder can be easily inserted in an actual database. Thereby, when a database leaks, an access right person can be easily specified by a dummy entry.

  Next, an unauthorized outflower identification processing procedure for identifying an access right holder who is an unauthorized outflower when the database is illegally outflowed will be described with reference to a flowchart.

  In addition, as an example of the access right person specifying process shown below, it is included in a processing procedure (first access right person specifying process) for specifying an unauthorized outflow person from an illegally leaked database and an illegally leaked database. A processing procedure (second access right person specifying process) for specifying an unauthorized outflow person when an e-mail (spam mail) is distributed using the e-mail address currently used will be described.

<Unauthorized Outflow Detection Processing Procedure: First Access Right User Identification Processing>
FIG. 8 is a flowchart illustrating an example of a first access right person specifying process procedure in the unauthorized outflow detection process. In FIG. 8, a database that has been illegally leaked is acquired (S11), and dummy entries are extracted from the acquired database by the extraction method described above (S12).

  Next, a set of extracted data entries is generated (S13), and a code word is generated from the dummy entry set based on, for example, the conditions shown in the above-described equation (1) (S14). Further, the access right person is specified from the bit string of the code word generated in S14 as described above (S15).

  By the above-described processing, it is possible to realize with high accuracy the identification of the access right person who is involved in the unauthorized leakage of the database. In addition, the illegal outflow detection process can be realized at low cost. Further, by installing the program, it is possible to easily realize the illegal outflow detection process.

<Unauthorized Outflow Detection Processing Procedure: Second Access Right User Identification Processing>
Next, a processing procedure (second access right person specifying process) for specifying an unauthorized outflow person when an email address included in the illegally outflowed database is used for spam mail will be described.

  FIG. 9 is a flowchart illustrating an example of a second access right person identifying process procedure in the unauthorized outflow detection process. In FIG. 9, first, a spam mail is transmitted from an unauthorized user to a mail address included in the provided database, the spam mail is received, and a dummy entry is acquired from the mail destination (S21).

  Next, a set of dummy entries acquired in S21 is generated (S22), and a code word is generated from the set of dummy entries based on, for example, the condition shown in the above-described equation (1) (S23). Next, the access right person is specified from the bit string of the code word generated in S23 as described above (S24).

  By the above-described processing, it is possible to realize with high accuracy the identification of the access right person who is involved in the unauthorized outflow of the database. In addition, even if the database itself such as leaked customer information cannot be obtained, if the email address contained in the database is used for spam mail distribution etc., the leakage of the database using that destination ( It is possible to identify the access right person who was involved in the fraud. In addition, the illegal outflow detection process can be realized at low cost. Further, by installing the program, it is possible to easily realize the illegal outflow detection process.

  As described above, according to the present invention, it is possible to identify the access right person who is involved in the unauthorized outflow of the database with high accuracy. In the present invention, the hamming weight can be adjusted by adjusting only the outer code without modifying the inner code when using the c-secure code. In particular, the outer code is allowed to have a non-uniform appearance frequency of the inner code, and in particular, by increasing the appearance frequency of a code word having a small Hamming weight in the outer code, the Hamming weight of the entire c-secure code is reduced. can do.

  In addition, even if the database itself such as leaked customer information cannot be obtained, if the email address contained in the database is used for spam mail distribution etc., the leakage of the database using that destination ( It is possible to identify the access right person who was involved in the fraud.

  In the above-described embodiment, the case where the fraudulent leaker is mainly identified from the email address included in the entry has been described. However, the present invention is not limited to this. For example, other information included in the dummy entry (for example, When a direct mail or the like is sent using an address, telephone number, FAX number, etc.), a dummy entry is extracted from the information, and the extracted dummy entry is collected. The access right holder can be specified based on the above.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be changed.

It is a figure which shows the schematic structural example of an unauthorized outflow detection system. It is a figure which shows an example of a function structure of the unauthorized outflow detection server in this embodiment. It is a figure which shows an example of the database in this embodiment. It is a figure which shows an example of the c-secure code | symbol in this embodiment. It is a figure which shows an example of the database provided to the access right holder in this embodiment. It is a figure which shows an example of the hardware constitutions which can implement | achieve the illegal outflow detection process in this invention. It is a flowchart which shows an example of the database provision process sequence in an unauthorized outflow detection process. It is a flowchart which shows an example of the 1st access right person specific process procedure in an unauthorized outflow detection process. It is a flowchart which shows an example of the 2nd access right person specific process procedure in an unauthorized outflow detection process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Unjustly leaked person detection system 11 Unjustly leaked person detection server 12 Access right person terminal 13 Communication network 21 User management means 22 Codeword generation means 23 Codeword allocation means 24 Dummy entry management means 25 Data generation means 26 Unauthorized leaker identification means 27 Transmission / reception means 28 Dummy DB
31 Input Device 32 Output Device 33 Drive Device 34 Auxiliary Storage Device 35 Memory Device 36 CPU
37 Network connection device 38 Recording medium

Claims (6)

An fraud consisting of an access right terminal used by an access right person and an unauthorized outflow detection server that identifies the access right person involved in the illegal outflow when the database provided to the access right terminal is illegally leaked In the spill detection system,
The unauthorized outflow detection server obtains a dummy entry different from an actual database entry by a codeword allocating unit that allocates a different codeword for each access right user using a c-secure code. Generated based on the length of the codeword, and the dummy entry management means that manages the generated dummy entry in association with the codeword, and is managed in association with the codeword by the dummy entry management means. A dummy database for storing dummy entries, and at least one dummy entry corresponding to the codeword assigned to the access right holder by the codeword assigning means is extracted from the dummy database, and the extracted dummy entry is a database to be provided to the access terminal A data generating means to insert, to generate the illegally included in the outflow database to extract the dummy entry, extracted said codeword allocated from the dummy entry for each of the access right person, the code An unauthorized leaker detection system comprising: an access right person specifying means for specifying an access right person corresponding to a word . In the unauthorized leaked person detection server that identifies the authorized accessor who has been involved in the unauthorized leak when the database provided to the authorized accessor terminal used by the authorized accessor is illegally leaked,
codeword assigning means for assigning different codewords for each access right using a c-secure code ;
Dummy entry management for generating a dummy entry different from an actual database entry based on the length of the codeword obtained by the codeword allocating means and managing the generated dummy entry in association with the codeword Means,
A dummy database for storing dummy entries managed in association with the codeword by the dummy entry management means;
At least one dummy entries corresponding to the codeword allocated to the access owner by the code word assignment means extracted from the dummy database, extracted the dummy entries to the database to be provided to the access terminal and data generation means to insert,
To generate a extract the dummy entries included in the unauthorized outflow database, allocated from the extracted dummy entry for each of the access right person the codeword, an access right holder corresponding to the codeword An unauthorized leaker detection server comprising: an access right person specifying means for specifying. The access right person specifying means is:
Wherein generating a code word from a set of dummy entries, the bit string of the generated code word, and identifies the access rights who by comparing the bit string of code words using the c-secure code The unauthorized outflow detection server according to claim 2 . The access right person specifying means is:
4. The unauthorized leaker detection server according to claim 2 , wherein an access right person is specified based on an e-mail distributed with the e-mail address included in the dummy entry as a destination. The codeword assigning means includes
The fraudulent outflower according to any one of claims 2 to 4 , wherein, in the c-secure code, an outer code is configured so that an appearance frequency of a code word having a small Hamming weight of the inner code is increased. Discovery server. Computer
6. A fraudulent outflow detection program that functions as the fraudulent outflow detection server according to any one of claims 2 to 5 .

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