JP2012182737A - Secret data leakage preventing system, determining apparatus, secret data leakage preventing method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To strongly prevent leakage of data including secret information without effort of a user and a manager of a document file.SOLUTION: A secret data leakage preventing system includes: image converting means converting file data into image data in a prescribed unit including at least one separation unit which is previously decided as an extraction unit of a feature amount; feature amount extracting means extracting the feature amount from the image data for every prescribed unit; protection object file information storing means storing protection object file information including the feature amount extracted from each image data for every prescribed unit as information of the protection object file; and determining means extracting the feature amount of each image data for every prescribed unit from the file data of an output object file, comparing the extracted feature amount and the feature amount of each image data for every prescribed unit in the stored protection object file and determining identity of the image to determine permission of an output request.

Description

  The present invention relates to a secret material outflow prevention system, a determination device, a secret material outflow prevention method, and a secret material outflow prevention program for preventing outflow of secret material.

  One of the major causes for the outside leakage or theft of confidential information due to deliberate or carelessness is the exchange of electronic data attached to an e-mail. As a method of preventing leakage of confidential information, there are methods of restricting the use of electronic files or detecting an attached file containing a keyword specified in advance.

  However, if an electronic file whose contents can be output as an image is copied and reused, it is difficult to prevent data distribution. For example, in the case of a PowerPoint (registered trademark) or a PDF file, if a part of the file is copied to another document file as an image, it is difficult to detect the leakage in the use restriction or keyword search in units of electronic files.

  Regarding the confidential document leakage prevention technology, for example, Patent Document 1 registers a print document that is a confidential document, an image image of an electronic file, and a feature amount extracted from the image image, and inputs an image in its own device. A document processing system is described that, upon detecting the start of output processing, transmits an image of a processing target image to a confidential document management apparatus and determines whether or not the processing target image matches a registered confidential document image. ing.

JP 2008-042636 A

  One of the major causes for the outside leakage or theft of confidential information intentionally or carelessly is the exchange of electronic data attached to an e-mail. As a method of preventing leakage, there are methods of restricting the use of electronic files and detecting attached files containing keywords specified in advance. However, a part of a PowerPoint or PDF file can be copied and reused. Once done, it is difficult to prevent data distribution.

  In Patent Document 1, the confidential document management device searches the image index from the image image received from the document processing device, the feature amount extracted from the image image, and the text information, and only completely matches the processing target image. In addition, it is described that even when there is registered data having a degree of similarity exceeding a predetermined threshold that partially matches the processing target image, the processing target image is determined to be a confidential document. However, there is no specific description of the partial match determination method in Patent Document 1, for example, when a part of a processing target file matches a part of a document file registered as a confidential document. Whether it can be detected is not certain. When the determination is made by calculating the similarity for each print document or document file registered as a confidential document, it may be considered that whether or not they match depends on the proportion of similar parts in the entire file.

  In the document processing system described in Patent Document 1, when the own apparatus detects the start of image input / output processing, a method of transmitting an image of the processing target image to the confidential document management apparatus is taken. For this reason, there is a problem in that leakage of image data including confidential information cannot be prevented unless an image input / output monitoring program or the like is installed in all terminals used by the user.

  Accordingly, the present invention provides a secret material outflow for preventing the outflow of secret material that can more securely prevent the outflow of data including confidential information without the effort of the user or administrator of the document file. It is an object of the present invention to provide a prevention system, a determination device, a secret material outflow prevention method, and a secret material outflow prevention program.

  A secret material leakage prevention system according to the present invention includes a protection target file data input means for inputting file data of a protection target file that is a file that contains secret information, and the input file data is used as a feature quantity extraction unit. Image conversion means for converting into predetermined unit image data including at least one predetermined delimiter unit, and feature quantity extraction means for extracting feature quantities from each of the predetermined unit image data obtained by the image conversion means; Protected file information storage for storing protected file information including feature quantities extracted from image data for each predetermined unit of the protected file as information of the protected file input by the protected file data input means And the output target file that is the file for which output is requested to the external device. Output target file data input means, and the feature quantity of each image data for each predetermined unit of the output target file is extracted from the file data of the output target file input by the output target file data input means, and the extracted feature quantity Each of the image data for each predetermined unit of the output target file is compared with each feature amount of each image data for each predetermined unit of the protection target file stored in the protection target file information storage means, and the protection target And determining means for determining permission / rejection of the output request by determining the identity of the image with each image data for each predetermined unit of the file.

  The determination apparatus according to the present invention is image data for each predetermined unit converted from file data of an output target file that is a file requested to be output to an external device, and is determined in advance as a feature value extraction unit. A feature amount is extracted from each image data for each predetermined unit including at least one delimiter unit, and each feature amount of each extracted image data and a protection that is a file containing confidential information in a predetermined storage means Compare each feature quantity extracted from each image data for each predetermined unit converted from the file data of the protection target file stored as information of the target file, and each for each predetermined unit of the output target file Judgment of whether or not the output request is permitted by judging the identity of the image between the image data and each image data for each predetermined unit of the protection target file Characterized by comprising a constant section.

  In addition, the secret material leakage prevention method according to the present invention uses the feature amount extracted from each image data converted from the file data of the protection target file as the information of the protection target file that is a file including the secret information. And storing protection target file information including feature amounts extracted from each predetermined unit of image data including at least one delimiter unit that is predetermined as a feature amount extraction unit, and requesting output to an external device The output target file, which is a file that has been processed, is input, the feature amount of each image data for each predetermined unit of the output target file is extracted from the file data of the output target file, and each extracted feature amount is stored. Each of the image data for each predetermined unit of the output target file by comparing the feature amount of each image data for each predetermined unit of the protection target file And over data, by determining the identity of the image between the predetermined unit different for each image data to be protected file, and judging approval or disapproval of the output request.

  Further, the secret material leakage prevention program according to the present invention is a feature amount extracted from each image data converted from the file data of the protection target file as information of the protection target file that is a file that contains secret information. And a protection target file information storage unit that stores protection target file information including feature amounts extracted from each of predetermined units of image data including at least one delimiter unit that is predetermined as a feature amount extraction unit. Or when a file access output request to an external device is detected by a computer accessible to the protection target file information storage means, each file for each predetermined unit of the output target file is detected from the detected file data of the output target file. Extract the feature values of the image data, and extract each feature value and the stored protection target file. The image data between each image data for each predetermined unit of the output target file and each image data for each predetermined unit of the protection target file. It is characterized in that processing for determining whether or not an output request is permitted is executed by determining the characteristics.

  According to the present embodiment, it is possible to more securely prevent the data including confidential information from leaking without taking the trouble of the user or administrator of the document file.

It is a block diagram which shows the structural example of the data management system to which the secret data outflow prevention method by this invention is applied. (A) is explanatory drawing which shows the example of the document information memorize | stored in document DB34, (B) is explanatory drawing which shows the example of the feature-value information memorize | stored in feature-value DB35. It is a sequence diagram which shows an example of operation | movement (material preparation operation | movement) of the material management system of this embodiment. It is a sequence diagram which shows an example of operation | movement (copy material attachment mail transmission operation | movement) of the material management system of this embodiment. It is explanatory drawing which shows the example of the identity judgment object between image data. It is a block diagram which shows the outline | summary of this invention. It is a block diagram which shows the other structural example of the secret data outflow prevention system by this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example when the method for preventing secret material leakage according to the present invention is applied to a material management system. The material management system shown in FIG. 1 includes a material creator terminal 10, a material duplicator terminal 20, a document management server 30, a feature amount extraction server 40, a determination server 50, and a mail server 60. The material creator terminal 10, the material duplicator terminal 20, the document management server 30, the feature amount extraction server 40, the determination server 50, and the mail server 60 are a server device or a personal computer that operates by program control, and a portable terminal device. Are connected to each other via a network 100 such as the Internet.

  The document creator terminal 10 is an information processing apparatus such as a personal computer. The document creator terminal 10 accesses the document management server 30 in response to a user operation, and transmits document data through PowerPoint or PDF format via the network 100. create.

  The material duplicator terminal 20 is an information processing apparatus such as a personal computer, and accesses the document management server 30 in response to a user operation to edit file data in PowerPoint or PDF format. In addition, it has a function of transmitting an e-mail attached with edited file data to the determination server 50 via the network 100.

  The document management server 30 is an information processing apparatus such as a workstation / server installed in a cloud environment such as a data center. The document management server 30 includes a document recording unit 31, a feature amount recording unit 32, a feature amount transmitting unit 33, a document database (DB) 34, and a feature amount DB 35.

  The document storage unit 31 records the document information 341 of the file data received from the material creator terminal 10 in the document management DB 34. The feature amount recording unit 32 records the feature amount information 351 of the feature amount extracted from the file data in the feature amount DB 35. The feature amount transmission unit 33 refers to the feature amount information stored in the feature amount DB 35 and transmits the feature amount information to the determination server 40 via the network 100.

  The document DB 34 is a database that stores document information 341. The feature amount DB 35 is a database that stores feature amount information 351.

  FIG. 2A is an explanatory diagram illustrating an example of document information 341 stored in the document DB 34, and FIG. 2B is an explanatory diagram illustrating an example of feature amount information 351 stored in the feature amount DB 35. is there. As shown in FIG. 2A, the document information 341 may include a document code for identifying a document file, a file name, file data, a creator, and a creation date. That is, the document information 341 may be a document code, file data of the document file, and metadata of the document file. In the present embodiment, the document file to be protected may be a file that can contain confidential information, and the file format is not limited. Each file may or may not include character information. Note that the file format of the document file to be protected includes files such as PowerPoint (registered trademark) and PDF files that output contents as images to the outside, and data contents other than text such as diagrams and mathematical expressions. More preferably, it includes a file format that can contain information.

  As shown in FIG. 2B, the feature amount information 351 includes feature amount codes for identifying feature amount data, document codes of document files from which feature amounts are extracted, and feature amount extraction. It may include a page number as identification information for identifying the target range, and feature amount data indicating the actually extracted feature amount. In the present invention, when archiving a file, the feature amount is extracted for each predetermined delimiter unit of the file, such as for each slide, page, or book, by a feature amount extraction server 40 described later. It should be noted that, within a range that can be identified from the file data, a plurality of different units such as each page and each drawing can be provided as the feature quantity extraction unit. The feature quantity extraction unit includes at least one delimiter unit used to delimit the data of the file. This ensures completeness of file data. As a delimiter unit, for example, in consideration of the user's usage mode, when printing the file, the print area when delimited from the units that are normally used to delimit the output image of the file is the smallest. A unit (hereinafter referred to as a standard output minimum unit) may be used. Hereinafter, in the present embodiment, a case where a feature amount is extracted for each page is described as an example.

  The feature quantity extraction server 40 is an information processing apparatus such as a workstation server installed in a cloud environment such as a data center. The feature amount extraction server 40 includes an image conversion unit 41, a feature amount extraction unit 42, a recording unit 43, and a feature amount transmission unit 44.

  The image conversion unit 41 converts the file data received from the determination server 50 into an image file in a predetermined delimiter unit. The feature amount extraction unit 42 extracts the feature amount of each image file converted by the image conversion unit 41 using a video signature technique. The storage unit 43 stores the feature amount extracted by the feature amount extraction unit 42. The feature amount transmission unit 44 transmits the feature amount stored in the recording unit 43 to the document management server 30 and the determination server 50 via the network 100.

  The determination server 50 is an information processing apparatus such as a workstation / server installed in a cloud environment such as a data center. The determination server 50 includes a file extraction unit 51, a feature amount reference unit 52, a comparison unit 53, a determination unit 54, and a recording unit 55.

  The file extraction unit 51 extracts the attached file data of the email received from the material duplicator terminal 20. The feature amount reference unit 52 accesses the document management server 30 via the network 100 to refer to (acquire) the feature amount DB 35. The comparison unit 53 compares the feature amount referred to by the feature amount reference unit 52 with the feature amount stored in the recording unit 55. The determination unit 54 determines whether mail can be transmitted from the comparison result by the comparison unit 53, and instructs the material duplicator terminal 20 or the mail server 60 to perform processing. The recording unit 55 stores the feature amount of the attached file data extracted by the file extraction unit 51.

  The mail server 60 is, for example, an information processing apparatus such as a workstation server installed in a cloud environment such as a data center, and distributes an electronic mail permitted to be transmitted from the determination server 50.

  Next, the operation of this embodiment will be described. 3 and 4 are sequence diagrams showing an example of the operation of the material management system of this embodiment. FIG. 3 is a sequence diagram showing an example of a material creation operation by this system, and FIG. 4 is a sequence diagram showing an example of a duplicate material attached mail transmission operation by this system.

  First, the material creation operation will be described. In the example shown in FIG. 3, first, the material creator operates the material creator terminal 10 to store document information (file name, file data, creator, creation date, etc.) of the new document file A in the document management server 30. Is transmitted (step A1).

  For example, the document creator terminal 10 may access a URL for registering new document information in response to a user operation. In response to this, the document management server 30 transmits document information registration screen data to the material creator terminal 10. Then, the material creator terminal 10 displays a screen document information registration screen from the received data, and transmits the document information of the document file A to the document management server 30 in response to a user operation on the displayed document information registration screen. May be.

  When the document recording unit 31 of the document server 30 receives the document information from the material creator terminal 10, the document recording unit 31 transmits the file data to the feature amount extraction server 40 (step A2). At that time, in order to identify the file data of the file data, a document code (here, a document code that can identify the file as a registration target file) is assigned and transmitted together with the assigned document code. Also good.

  In the feature amount extraction server 40, the image conversion unit 41 converts the received file data into image data (JPEG format or the like) in units of one page (step A3). A method for converting file data of a document file into image data can be achieved by, for example, generating image data of a print image of each page of a target file by using a function of PowerPoint or existing software for imaging a PDF file. Good. The image conversion unit 41 temporarily stores in the recording unit 43 the image data for each page obtained by the conversion. When a plurality of units are provided as feature quantity extraction units, they may be converted into image data according to each unit. For example, after converting into image data for each predetermined delimiter unit, the image data is recognized, and when an area that is regarded as a drawing or table is detected, the image data in that area is converted to image data by drawing or For example, it may be generated as image data for each table.

  Next, the feature amount extraction unit 42 extracts feature amounts from the image data for each page obtained by the image conversion unit 41, associates the page number with the feature amount data, and stores the feature amount information in the recording unit 43. (Step A4).

  In the present invention, a video signature technique is used as a feature amount extraction method. As the video signature technique, for example, the technique described in Japanese Patent Application No. 2009-012810 may be used. More specifically, for one piece of image data, an image (display image) represented by the image data is divided into regions of various sizes and shapes, and region feature amounts are extracted, and region feature amounts between regions are extracted. A quantization index (image identifier) obtained by quantizing the comparison results of the above may be obtained as a feature amount for identifying the image. Examples of the region feature amount include an average value of luminance values, an average vector of RGB components, and a 5-bin histogram representing the edge direction distribution. Note that the feature amount extraction unit 42 determines the image size of the image data so that the size of the image represented by each image data is constant when the size of the image represented by each image data is different. The feature amount may be extracted after performing adjustment processing (image enlargement or reduction processing). The image size adjustment process may be performed when the image conversion unit 41 converts the image data into image data.

  When the feature amount information for the document file A is generated in this way, the feature amount transmission unit 44 transmits the generated feature amount information to the document management server 30 that is the request source (step A5).

  In the document management server 30, when the feature amount recording unit 32 receives feature amount information about a registration target file from the feature amount extraction server 40, a feature amount code is newly assigned to the feature amount information, and the document information is recorded by the document code. 341 and feature quantity information 351 are linked to each other and recorded in the document DB 34 and the feature quantity DB 35 (step A6). In this way, the document management server 40 stores information on document files to be protected by this system.

  Next, with reference to FIG. 4, the operation of sending duplicate material attached mail by this system will be described. In the example shown in FIG. 4, the material duplicator operates the material duplicator terminal 20 to copy a part of the document file A to the document file B as an image (step B1). Further, the material duplicator operates the material duplicator terminal 10 and transmits an e-mail attached with the document file B (step B2).

  For example, in response to a user operation, the material duplicator terminal 20 copies a part of the document file A as an image, and pastes and saves it on the document file B. Then, an e-mail attached with the saved document file B (a file including part of the contents of the document file A as image information) is created in response to a user operation, and the e-mail is sent to the mail server 60 in response to a transmission instruction from the user. Send to.

  At this time, in this embodiment, the determination server 50 first receives an e-mail transmission request message to the mail server 60 by the material duplicator terminal 20. For example, it may be transferred to the determination server 50 by setting a proxy server that relays from the internal network to the external network. In addition to the mode of receiving prior to the mail server 60, a mode of transferring the mail server 60 in a request for determining whether or not transmission is possible may be used. In other words, the network node provided in the system may be provided with an external output request detection means for detecting a request for transmitting file data or image data to an external network. When data output to external devices (such as non-authenticated peripheral devices) is included in the monitoring target as well as data transmission via the network, the data running on the terminal must be included in the software running on the terminal. External output request detection means for detecting an output request may be implemented.

  The file extraction unit 51 of the determination server 50 extracts the document file B (output target file) file data attached to the e-mail received from the material duplicator terminal 10 and transmits it to the feature amount extraction server 30 (step B3). . At this time, together with the file data of the document file B, a document code newly assigned to the file (a document code that can identify the file as an output document) may be transmitted.

  In the feature amount extraction server 40, first, the image conversion unit 41 converts the file data received from the determination server 50 into, for example, image data (JPEG format or the like) in units of one page (step B4). The image conversion unit 41 may temporarily store the image data for each page obtained by the conversion in the recording unit 43. Next, the feature amount extraction unit 42 extracts feature amounts from the image files for each page obtained by the image conversion unit 41 to obtain feature amount information (at this time, the document code of the file data, the page number of each page, And feature amount data), and is stored in the recording unit 43 (step B5). When the feature amount information for the document file B is generated in this way, the feature amount transmission unit 44 transmits the generated feature amount information to the determination server 50 that is the request source (step B6).

  When the determination server 50 receives the feature amount information about the output target file from the feature amount extraction server 40, the reference unit 52 accesses the document management server 40 after temporarily storing the received feature amount information in the recording unit 55. Then, the feature amount information about each document file (protection target file) stored in the feature amount DB 35 is referred to (step B7).

  The determination unit 54 is referred to by the reference unit 52 and the feature amount data of each page included in the feature amount information about the document file B (output target file) that is the determination target stored in the recording unit 55. The feature amount data of each page included in the feature amount information for each protected file is compared (step B8). In the present embodiment, the reference process and the comparison process may be finally performed on all the protection target files, and it does not matter whether the protection target files are referred to collectively or sequentially.

  FIG. 5 is an explanatory diagram illustrating an example of identity determination targets between image data. FIG. 5 illustrates a case where two pieces of image data are generated as the image data of the output target file. Also, two files (protection target files 1 and 2) are registered in the text DB 34 as protection target files, and three image data are generated as image data of the protection target file 1, and as image data of the protection target file 2. A case where one image data is generated is shown. In the example illustrated in FIG. 5, the determination unit 54 performs a process for determining the identity of a total of eight patterns of image data between each image data of the output target file and each image data of the protection target files 1 and 2. Will be done.

  In step B8, if there is at least one matching feature amount data, that is, it is determined that there is image identity between the image data of a page with an output target file and the image data of a page with all the protection target files. When the feature amount data matches to the extent that the file is matched, the determination unit 54 determines that the confidential information is included in the output target file, and warns the material duplicator terminal 20 that performed the output processing of the file. A screen is displayed (step B9). As a specific method for determining the identity of an image based on feature amount data, for example, in the case of using a plurality of dimensional quantization vectors obtained by the video signature technique described above as a feature amount, a quantization index value in each dimension If the disagreement index (the value obtained from the number of disagreement dimensions, the sum of the difference values in each dimension, etc.) is within a predetermined threshold%, the identity may be recognized.

  On the other hand, if there is no matching feature data, the determination unit 54 determines that the output target file does not contain confidential information, and sends an e-mail attached with the file to the mail server 60 that is the original transmission destination. Transmit (step B10). When the file data of the output target file is received from the mail server 60 in the form of an inquiry about whether or not transmission is possible, the determination unit 54 may send a response indicating that transmission is possible to the mail server 60 that is the inquiry source. Good.

  The mail server 60 distributes the electronic mail received from the determination server 50, that is, the electronic mail permitted to be transmitted (step B11).

  As described above, according to the present embodiment, it is possible to more securely prevent data including confidential information from being leaked without taking the trouble of the user or administrator of the document file. This is because the registration-side and output-side files are converted into image data in a predetermined delimiter unit, and the identity between the image data is determined. Furthermore, by using features extracted using video signature technology to determine the identity between image data, it is possible to detect reuse of image data at a high detection rate that cannot be detected by text keyword search. can do. For example, even if there is a partial rewrite or only one drawing in the page has been copied, the content of the entire page is not exactly the same, but the data can be reused with a high detection rate. Can be detected.

  In the above embodiment, as an example of the file output method, an example of transmitting by attaching to an e-mail has been shown. However, the file output method is not limited to this method, and a file or image data is output to the outside at a network node. Any protocol that can recognize this can be applied by the same method. For example, file transfer by FTP or transmission of HTML data described to include image data in the data element may be used.

  In the above-described embodiment, an example in which all the files to be protected are targeted in the feature amount comparison has been described. For example, when data of a protection target file is reused (for example, data is copied and pasted from a document file) If the document code is stored in the output target file, only the protection target file stored as the use source (copy source) file in the output target file can be compared.

  Next, the outline of the present invention will be described. FIG. 6 is a block diagram showing an outline of the present invention. As shown in FIG. 6, the secret material leakage prevention system according to the present invention includes a protection target file data input means 101, an image conversion means 102, a feature amount extraction means 103, a protection target file information storage means 104, and an output target. File data input means 105 and determination means 106 are provided.

  The protection target file data input unit 101 (for example, the document recording unit 31) inputs file data of a protection target file that is a file that includes secret information.

  The image conversion unit 102 (for example, the image conversion unit 41) converts the input file data into image data of a predetermined unit including at least one delimiter unit that is predetermined as a feature amount extraction unit.

  The feature amount extraction unit 103 (for example, the feature amount extraction unit 42) extracts a feature amount from each of the image data for each predetermined unit obtained by the image conversion unit 102.

  The protection target file information storage unit 104 (for example, the document DB 34), as the information on the protection target file input by the protection target file data input unit, is extracted from each image data for each predetermined unit of the protection target file. The protection target file information including is stored.

  The output target file data input means 105 (for example, the file extraction unit 51) inputs an output target file that is a file for which an output request has been made to an external device.

  The determination unit 106 (for example, the reference unit 52, the comparison unit 53, and the determination unit 54) determines each image data for each predetermined unit of the output target file from the file data of the output target file input by the output target file data input unit 105. Are extracted, and each extracted feature amount is compared with each feature amount of each image data for each predetermined unit of the protection target file stored in the protection target file information storage unit 104, and the output target Whether or not the output request is permitted is determined by determining the identity of the image between each image data for each predetermined unit of the file and each image data for each predetermined unit of the file to be protected.

  The feature amount extraction unit may extract the feature amount from the image data using a video signature technique.

  Further, the standard output minimum unit may be used as the delimiter unit. Further, a page unit, a slide unit, or a book unit may be used as a delimiter unit. A plurality of different units may be defined as the predetermined unit as the feature quantity extraction unit.

  In addition, as shown in FIG. 7, the secret material leakage prevention system further includes an external output detection unit 107 (for example, a mail server 60 or a network server) that detects a transmission request for an email attached with a file in a network node included in the system. A proxy server (not shown) may be provided.

  In particular, the present invention can be suitably applied to a use for preventing external leakage or theft of confidential information intentionally or carelessly. Further, the present invention can be preferably applied to a form in which a document file including secret information is used in a cloud environment.

DESCRIPTION OF SYMBOLS 100 Network 10 Material creator terminal 20 Material duplicator terminal 30 Document management server 31 Document recording part 32 Feature quantity recording part 33 Feature quantity reference part 34 Document DB
35 Feature DB
DESCRIPTION OF SYMBOLS 40 Feature-value extraction server 41 Image conversion part 42 Feature-value extraction part 43 Recording part 50 Determination server 51 File extraction part 52 Reference part 53 Comparison part 54 Determination part 55 Recording part 101 Protection target file data input means 102 Image conversion means 103 Feature-value Extraction means 104 Protection target file information recording means 105 Output target file data input means 106 Determination means 107 External output detection means

Claims (9)

Protected file data input means for inputting file data of a protected file that is a file that contains confidential information;
Image conversion means for converting input file data into image data of a predetermined unit including at least one delimiter unit predetermined as a feature value extraction unit;
Feature amount extraction means for extracting feature amounts from each of the predetermined unit of image data obtained by the image conversion means;
Protection target file information for storing protection target file information including feature quantities extracted from the image data for each predetermined unit of the protection target file as information on the protection target file input by the protection target file data input means Storage means;
An output target file data input means for inputting an output target file that is a file requested to be output to an external device;
Extracting the feature quantity of each image data for each predetermined unit of the output target file from the file data of the output target file input by the output target file data input means, each extracted feature quantity, and the protection target file Each feature value of each image data for each predetermined unit of the protection target file stored in the information storage unit is compared, and each image data for each predetermined unit of the output target file is compared with the predetermined value of the protection target file. A secret material outflow prevention system comprising: a determination unit that determines whether or not the output request is permitted by determining the identity of an image with each unit of image data. The secret material leakage prevention system according to claim 1, wherein the feature amount extraction unit extracts a feature amount from the image data using a video signature technique. The secret data leakage prevention system according to claim 1 or 2, wherein the standard output minimum unit is used as a delimiter unit. The secret material leakage prevention system according to any one of claims 1 to 3, wherein a page unit, a slide unit, or a book unit is used as a delimiter unit. The secret material outflow prevention system according to any one of claims 1 to 4, wherein a plurality of different units are defined as the predetermined unit as a feature quantity extraction unit. The secret material leakage prevention system according to any one of claims 1 to 5, further comprising an external output detection unit that detects a transmission request for an e-mail attached with a file in a network node included in the system. A predetermined unit including at least one delimiter unit, which is image data for each predetermined unit converted from the file data of the output target file, which is a file requested to be output to an external device, and is predetermined as a feature amount extraction unit. A feature amount is extracted from each unit of image data, and each feature amount of each extracted image data is stored as information on a protection target file, which is a file that contains confidential information in a predetermined storage means. Each feature data extracted from each image data for each predetermined unit converted from the file data of the protection target file is compared with each image data for each predetermined unit of the output target file, and the protection target file Determining means for determining whether or not the output request is permitted by determining the identity of the image data with the image data for each predetermined unit. Determination and wherein the. Information on the protection target file, which is a file that contains confidential information, is a feature amount extracted from each image data converted from the file data of the protection target file, and is predetermined as a feature amount extraction unit. Storing protection target file information including feature amounts extracted from each predetermined unit of image data including at least one delimiter unit,
An output target file, which is a file requested to be output to an external device, is input, and the feature amount of each image data for each predetermined unit of the output target file is extracted from the file data of the output target file and extracted. Each feature amount is compared with each feature amount of each stored image data for each predetermined unit of the protection target file, and each image data for each predetermined unit of the output target file is compared with the protection target file. A method for preventing secret material outflow, wherein whether or not the output request is permitted is determined by determining the identity of each image data with respect to each predetermined unit of image data. Information on the protection target file, which is a file that contains confidential information, is a feature amount extracted from each image data converted from the file data of the protection target file, and is predetermined as a feature amount extraction unit. A protection target file information storage unit for storing protection target file information including feature quantities extracted from each predetermined unit of image data including at least one delimiter unit, or accessible to the protection target file information storage unit On the computer,
When an output request for file data to an external device is detected, the feature amount of each image data for each predetermined unit of the output target file is extracted from the file data of the detected output target file, and the extracted feature amount Each of the image data is compared with each feature amount of each image data for each predetermined unit of the protection target file stored, and each image data for each predetermined unit of the output target file is compared with the predetermined amount of the protection target file. A secret material outflow prevention program for executing a process for determining whether or not an output request is permitted by determining the identity of an image with each unit of image data.

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