JP4897782B2 - Document management system, document management method, and program thereof - Google Patents

Description

  The present invention relates to a document management system, a document management method, and a program thereof, and more particularly, to a document management system, a document management method, and a program thereof that can encrypt and download a document for browsing after downloading.

  In the document management system, document security is ensured by access restrictions. However, once a document is downloaded by the client, no security can be applied to the document. For this reason, if the document is downloaded and illegally distributed, the security on the document management system is not ensured. As one example, in Patent Document 1, authentication is performed to determine whether or not the user is a valid user by comparing authentication information with the one-time password generated by the one-time password generation means. And a decryption key for decrypting the encrypted file when the user is authenticated by the authentication means and authenticating the user to the other terminal device, and sending the decryption key to the other terminal device. An electronic file management system characterized by further comprising decryption key transmission means for executing decryption of an encrypted file is disclosed.

JP 2007-286935 A

  However, the electronic file management system and the electronic file management program described in Patent Document 1 can store the decrypted file in the USB memory and the portable storage device after authentication.

The present invention has been made to solve the above-described problem, and when a document managed by a document management server is downloaded and viewed from a browsing terminal , the downloaded document is divided and encrypted, It is an object of the present invention to provide a document management system, a document management method, and a program thereof that can ensure high security against information leakage by decrypting and browsing a portion that a user wants to browse .

The present invention is a document management system configured such that a document server and a browsing terminal can communicate with each other, wherein the document server stores a document storage unit that stores a document to be managed, and a document browsing request from the browsing terminal. browsing request receiving means for receiving, in response to the viewing request receiving means and the viewing request is received, dividing the browsing requested document, and split encryption means for encrypting using the encryption information, the viewing A document transmission unit that transmits the encrypted document to the browsing terminal that transmitted the request, and the browsing terminal includes a browsing request transmission unit that transmits a document browsing request to the document server, and the browsing request transmission unit. in response to the transmitted said read request, the divided and encrypted document storage means for receiving and storing the encrypted document from the document server, the encrypted document to the divided and the storage And page designation means for designating a desired viewing page, the desired viewing page previous SL page specifying means specified, the first decoding means for decoding using the encrypted information, the first And page display means for displaying the page decrypted by the decrypting means .
The browsing terminal further includes a determination unit that determines whether communication with the document management server has been established, and the first decryption unit has the determination unit that has established communication with the document management server. The divided and encrypted document is decrypted when it is determined, and the divided and encrypted document is not decrypted when the determination unit determines that the communication is not established. .
In addition, the browsing terminal further includes a second decoding unit that decodes a divided page next to the desired browsing page specified by the page specifying unit, and the second decoding unit includes the second decoding unit, When the page designation means displays the desired browsing page, the page divided by the page divided by the page displayed by the page display means is decoded and stored.
The document server includes a calculation unit that calculates capacity information for each divided and encrypted document, and an addition unit that adds the capacity information to the encryption information.
The document transmission means transmits encrypted information including the capacity information to the browsing terminal.
The browsing terminal further includes a deleting unit that deletes the decrypted document stored in the storage unit, and the deleting unit includes the browsing page displayed by the page display unit and the decoded browsing page. This is characterized in that a page that is not, and a decrypted and stored document is deleted from the storage unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing a system configuration of a document system according to an embodiment of the present invention. The document management server 100 is configured to be able to communicate with the document management server 100 via the communication line 300. Various tables and print forms are stored in the hard disk of the external memory 211 of the document management server 100. A document browsing request is transmitted from the client 200 to the document management server 100 via the communication line 300, and the document management server 100. Transmits the document to the client 200 after encrypting the document.

  Next, FIG. 2 is a schematic diagram illustrating a schematic configuration of hardware of the document management server 100 and the client 200. The CPU 201 comprehensively controls each device and controller connected to the system bus 204. In addition, the ROM 202 or the external memory 209 realizes a function of executing a basic input / output system (BIOS), an operating system program (hereinafter referred to as OS), which is a control program of the CPU 201, and each program of the document management server 100. Various programs and the like which will be described later are stored.

  The RAM 203 functions as a main memory, work area, and the like for the CPU 201. The CPU 201 implements various operations by loading a program necessary for execution of processing into the RAM 203 and executing the program. The input controller 205 controls input from a pointing device such as a keyboard (KB) 209 or a mouse (not shown). The video controller 206 controls display on a display device such as a CRT display (CRT) 210. The display device may be a liquid crystal display as well as a CRT.

  The memory controller 207 is stored in a hard disk (HD), floppy (registered trademark) disk (FD), or PCMCIA card slot for storing a boot program, browser software, various applications, font data, user files, editing files, various data, and the like. Controls access to an external memory 211 such as a compact flash (registered trademark) memory connected via an adapter. The communication I / F controller 208 is connected to and communicates with an external device via a network, and executes communication control processing on the network. For example, network communication using TCP / IP is possible.

  The hard disk of the external memory 211 is screen information as a part of the operating system, the application program shown in the flowcharts of FIGS. 3 to 7, and the application program for displaying each screen shown in FIGS. 8 to 11 on the display of the client 200. Each database, table, and master file such as the document management DB shown in FIG. 12 and the user master shown in FIG. 13 are stored. The client 200 may use a nonvolatile memory that is also used as the RAM 203 instead of the hard disk of the external memory 211.

  Note that the CPU 201 enables display on the CRT 210 by executing outline font rasterization processing on a display information area in the RAM 203, for example. In addition, the CPU 201 enables a user instruction with a mouse cursor (not shown) on the CRT 210.

  Here, the table and the master file will be described. The document management DB shown in FIG. 12 includes a unique document number (key), a document name, a document type (a document type such as a plan, a proposal, a specification, a minutes, etc.), a confidential rank (described later), a creator ID (document creator's user ID), storage location (full document path + document file name), creation date (document creation date), revision date, revision ID (user revision last user ID) Each item of storage expiration date (document storage expiration date, 99999999 is stored for many years) is stored. The confidential rank of the document management DB indicates that access is possible when the confidential rank of the user master described later is equal to or higher than the confidential rank of the document management DB. For example, the confidential rank S of the document management DB can be accessed only by a person whose confidential rank of the user master is S rank, and the confidential rank C of the document management DB is accessed by a person whose confidential rank of the user master is S rank to C rank. It shows that it is possible. The actual data of the secret rank is stored as S rank 7, A rank 6, B rank 5, C rank 4, D rank 3, E rank 2, F rank 1. If the confidential rank of the document management DB is F rank (1), it means that the person of F rank of the user master can access, and this means that this document is a general document that is not confidential.

  The user master shown in FIG. 13 stores items such as a unique user ID (key item), name, belonging organization code, confidential rank, position, e-mail address, extension telephone number, and belonging domain. For example, S is an officer or higher, A is the head of the business department, B is the head of the department or equivalent, C is the department manager or equivalent, D is the section manager or equivalent, E is the manager or equivalent, and F is a general position Indicates. The actual data of the secret rank stores 7 to 1 for the S rank to F rank as in the document management DB. The secret rank indicates which rank of the confidential document can be accessed. For example, S (7) can access the confidential document of the entire company, A can access the confidential document of the business department to which the company belongs, B is the headquarters to which the company belongs. Can access confidential documents, C can access confidential documents in the department to which he belongs, D can access confidential documents in the department to which he belongs, E can access confidential documents created by himself, F can access confidential documents It means you can't. The belonging domain indicates the domain of the network to which the user's PC is connected.

  The organization master shown in FIG. 14 includes a unique organization code (key), organization name, organization rank (5 to 1, the higher organization is a larger number), organization manager user ID (line length user ID), and higher organization code. 1 (Organization code one level above the organization), Higher organization code 2 (Organization code two levels above the organization), Upper organization code 3 (Organization code three levels above the organization) , Upper organization code 4 (organization code four levels above the organization), organization reorganization date (date when the organization started), organization abolition date (date when the organization was abolished) Each item of the old organization code (the organization code of the old organization in the case of an organization change) is stored. For example, the organizational rank means 5 for the business division, 4 for the head office, 3 for the division, 2 for the section, and 1 for the section. For example, when the upper organization code is a section, the upper organization code 1 is the organization code of the department including the section, the upper organization code 2 is the organization code of the headquarters including the section, and the upper organization code 3 is the organization of the business department including the section Indicates the code. The document management master shown in FIG. 15 stores the presence / absence of encryption for each extension, and the extension (key item) attached to the end (after.) Of the document file name and the encryption classification (encryption required). 1 is stored, and encryption is not required: 0).

  Next, a basic processing flow of the encryption / decryption system of the document management system will be described with reference to FIG. FIG. 3 is a diagram showing a basic processing flow of the encryption system of the document management system according to the embodiment of the present invention. Steps 101 to 107 in FIG. 3 are processes executed under the control of the CPU 201 of the client 200, and steps 121 to 126 are processes executed under the control of the CPU 201 of the document management server 100.

  First, in step 101, the client 200 transmits, to the document management server 100, login information including information specifying a user ID, a password, and a domain name to which the user belongs, via an operation screen provided from the document management server 100. To do. In step 121, the document management server 100 stores the received login information in the work area of the RAM 203, refers to the user master using the user ID of the login information as a key, and authenticates the user as to whether the user ID and password match. I do. If the user ID and password do not match, the document management server 100 sends an error message to the client 200. The client 200 receives the login permission message, displays the error message, and then inputs the user ID and password again to manage the document. Send to server 100. When the user ID and the password match, the document management server 100 transmits a login permission message and operation screen information for causing the client 200 to display an operation screen.

  In step 102, the client 200 receives the login permission message and advances the process to step 103. In step 103, the client 200 receives document search request information (including user ID and search condition information via the operation screen displayed using the operation screen information received from the document management server 100. Or the part of the document, the document creator name, the document creation date, etc.).

  In step 122, the document management server 100 searches the document management DB using the document search condition information included in the search request information received from the client 200, and bibliographic information (document number and document number) of the document that matches the search condition. The document name, creator, revision date, etc.) are stored in the work area of the RAM 203, and the process proceeds to step 123. Specifically, referring to the user master using the user ID as a key, the confidential rank and organization code of the user are obtained, and in the search of the document management DB, the search condition information and the confidential rank are used. A document that matches the information and has a confidential rank corresponding to the user ID is searched. That is, for example, if the confidential rank of the user is C rank, a document whose document confidential rank is C rank to F rank is searched. When the name of the document creator is included in the search condition, the document management DB is searched with the search condition including the user ID by referring to the user master by name and acquiring the user ID. It should be noted that the user ID of the user who is going to download and view the document is referred to the user master, the confidential rank and the organization code of the user who is going to browse are acquired, and the organization master shown in FIG. Whether or not viewing is possible can be determined by determining the relationship between the organization of the user who created the document with reference to the organization of the user who is downloading and viewing the document.

  In step 123, the document management server 100 uses the bibliographic information of the documents stored in the work area of the RAM 203 to display screen information for displaying a list screen (search result list) of documents matching the search condition on the client 200. Is stored in the work area of the RAM 203, and in step 124, the document management server 100 transmits the created search result list screen information to the client 200. In step 104, the client 200 that has received the screen information for the search result list from the document management server 100 displays the search result list on the screen G100 in FIG.

  In step 105, the client 200 selects a document to be downloaded from the search result list screen, and transmits selection information for identifying the selected document to the document management server 100 together with the user ID. In step 125, the document management server 100 converts the user ID at the time of user login and a unique ID (such as a Mac address) that can identify the client machine into a function-operated one, creates an encryption key, and creates a work in the RAM 203. Store in the area and proceed to step 126. In step 126, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display an encryption processing in progress screen (screen G101 in FIG. 8), and the document specified by the selection information is stored in the work area of the RAM 203. The encrypted document is transmitted to the client 200, and the document before encryption is deleted. A detailed flowchart of the encryption process is shown in FIG. 5 and will be described later.

  In step 106, the client 200 receives the encrypted document, stores it in the work area of the RAM 203, decrypts it in units of pages, and performs a browsing process. A detailed flowchart of browsing is described in FIG. 7 and will be described later.

  Next, FIG. 4 is a diagram showing a basic processing flow of the decryption system of the document management system according to the embodiment of the present invention. The decryption system is a process for uploading a document from the client 200 to the document management server 100. Steps 201 to 203 in FIG. 4 are processes executed under the control of the CPU 201 of the client 200, and steps 221 to 224 are processes executed under the control of the CPU 201 of the document management server 100.

  First, in step 201, the client 200 transmits login information including a user ID, a password, and the like to the document management server 100 via an operation screen (login) displayed using the screen information received from the document management server 100. To do. In step 221, the document management server 100 authenticates the user based on the user information by the same process as in step 121 of FIG. When the user ID and the corresponding password match, message information for permitting login is transmitted to the client 200.

  In step 202, the client 200 displays message information and proceeds to step 203. In step 203, a desired already encrypted document is selected on the operation screen, and the selected encrypted document and the bibliography of the encrypted document are selected. Information (secret rank, document type, creator ID or revision ID, storage expiration date) is transmitted to the document management server 100 together with the user ID.

  In step 222, the document management server 100 receives the encrypted document, bibliographic information, and user ID transmitted from the client 200, stores them in the work area of the RAM 203, and advances the process to step 223. In step 223, the encrypted document stored in the work area of the RAM 203 is decrypted. A detailed flowchart of the decoding process is described in FIG. 6 and will be described later.

  In step 224, the document management server 100 registers the decrypted document. Specifically, the decrypted document is moved to a predetermined folder, and bibliographic information is registered in the document management DB. If the decrypted document already exists, it is replaced with a predetermined folder, and the bibliographic item including the full path and file name stored in the document management DB is overwritten. This is the end of the description of the flowchart of FIG.

  Next, FIG. 5 is a flowchart showing the details of the encryption process (step 126) of the server 125 in the encryption system of FIG. 3 of the document management system according to the embodiment of the present invention. Step 331 is processing executed under the control of the CPU 201 of the document management server 100. First, in step 301, the encryption key created in step S125 is moved from the work area of the RAM 203 to a predetermined register of the CPU 201, and the process proceeds to step 302. In step 302, the work area of the RAM 203 is referred to, the user master is referred to using the user ID of the user who requested the document as a key, the domain to which the user belongs is obtained, and it is determined whether to execute the encryption process. If the document is not encrypted, the document management server 100 and the client 200 used by the user are in the same domain. If the domain is not encrypted, the process proceeds to step 320. In step 320, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display an original file download dialog. Using the received screen information, the client 200 displays an original file download dialog and ends the process.

  If the domain is to be encrypted (when the document management server 100 and the client 200 used by the user are in the same domain), the process proceeds to step 303. In step 303, the document management server 100 refers to the document management master shown in FIG. 15 using the extension of the selected document as a key, stores the encryption classification in the work area of the RAM 203, and advances the process to step 304. In step 304, it is determined whether the extension is an encryption target extension using the encryption classification stored in the work area of the RAM 203. If the extension is not the encryption target extension, the process proceeds to step 320. In step 320, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display an original file download dialog. Using the received screen information, the client 200 displays an original file download dialog and ends the process.

  If it is determined in step 304 that the extension is to be encrypted, the process proceeds to step S305. In step 305, the document management server 100 displays screen information for causing the client 200 to display a subwindow indicating that encryption processing is in progress. 200. The client 200 displays a sub-window (G101 in FIG. 8) indicating that encryption processing is in progress using the received screen information, and advances the processing to step S306. In step 306, the document to be encrypted is encrypted in units of pages using the encryption key storing the document in the register of the CPU 201, and the encrypted data in units of pages is stored together with the number of bytes of the encrypted data in the work area of the RAM 203. After all the pages are encrypted, the address when merging is calculated using the start address and end address of each page, and the header information (of the encrypted document) is calculated before the encrypted document body. This is a kind of jump table that uses the number of bytes per page to record the number of each page, the first address of the encrypted file where the encrypted data of this page starts, and the last address where the encrypted data of this page ends. Create an encrypted document with the table of contents information) and add the encrypted document to the encrypted folder. Storing the instrument advances to step 307 to save the encryption key created in 125 of FIG. 3 in the encryption key table (not shown) process.

  In step 307, the existence of the encrypted file is confirmed. If there is no encrypted file and the encryption fails (encryption error) or a timeout (an error that the encryption is not completed within a predetermined time) occurs, the process is performed. The process proceeds to step S330. In step 330, an error log file including the details of the error that has occurred (error type, date of occurrence, user ID, document name) is output, and the process proceeds to step 331. In step 331, when the generated error is an encryption error, the document management server 100 transmits to the client 200 screen information for displaying the encryption error screen on the client 200, and the client 200 receives the received screen information. Is used to display an encryption error screen (G105 in FIG. 8). In the case of a timeout error, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display a timeout error screen, and the client 200 uses the received screen information to display a timeout error screen (FIG. 8). G103) is displayed and the process is terminated. If there is an encrypted file in step 307, the process proceeds to step 308. In step 308, the document copied to the encrypted folder (unnecessary file whose capacity after encryption is zero) is deleted and the process is performed. Go to 309.

  In step 309, the document management server 100 transmits screen information for displaying the download screen of the encrypted file on the client 200 to the client 200, and the process proceeds to step 310. The client 200 displays an encrypted file download screen (G102 in FIG. 8) using the received screen information. In step 310, when the document management server 100 receives from the client 200 information indicating that the download button has been pressed (clicked) on the client 200, the process proceeds to step 311. In step 311, the document management server 100 transmits screen information for causing the client 200 to display a download dialog, and waits for a response from the client 200. The client 200 displays a download dialog (G104 in FIG. 8) on the screen using the received screen information. When the document management server 100 receives information indicating that the “open” button or the “save” button has been pressed from the return client 200, the document management server 100 starts downloading the encrypted document to the client 200. Proceed to 312. In step 312, the document management server 100 deletes the encrypted document remaining in the encrypted folder, transmits to the client 200 screen information indicating that the encrypted document download screen (G 102 in FIG. 8) is closed, and the client 200. Closes the download screen. This is the end of the description of FIG.

  FIG. 6 is a flowchart showing details of the decryption processing of the document management server 100 in the decryption system of FIG. 4 of the document management system according to the present invention.

  First, in step 401, the document management server 100 refers to the document management DB using the file name as a key, determines whether the uploaded document is a new addition or an update (version addition), and The determination result is stored in the work area of the RAM 203, and the process proceeds to step 402.

  In step 402, the document management server 100 refers to the document management master using the file extension as a key, acquires the encryption classification, stores it in the work area of the RAM 203, and proceeds to step 403. In step 403, the document management server 100 determines whether the document is to be decrypted using the encryption classification stored in the work area of the RAM 203. If it is determined that the document is to be decrypted, the process proceeds to step 404. On the other hand, if the extension is not subject to decryption, the process proceeds to step 420. In step 420, the document management server 100 stores the document in the document management server 100 (stores the document in a predetermined folder, Process for registering bibliographic information in the management DB), and the process proceeds to step S414. In step 414, the document management server 100 transmits screen information for causing the client 200 to display a list screen (G200 in FIG. 9) to the client 200, and the client 200 uses the received screen information to display the list screen (FIG. 9 G200) is displayed and the process is terminated.

  On the other hand, when it is determined in step 403 that the extension is to be decrypted, in step 404, the document management server 100 displays screen information for causing the client 200 to display a screen (G204 in FIG. 10) indicating that decryption processing is in progress. The client 200 displays a screen (G204 in FIG. 10) indicating that the decryption process is being performed using the received screen information. During this time, the document management server 100 uses the encryption key created by functionally operating the user ID at the time of login of the client 200 and a unique ID (Mac address or the like) that can identify the client machine in the same manner as in step 125. If the same encryption key is stored with reference to the encryption key table of the server, the document is decrypted using this encryption key, and the process proceeds to step 405. If the decryption process is successful, an empty “.success” file is created. On the other hand, if the decryption processing fails, a “.error” file including error contents (for example, error contents such as extension and document contents do not match) is created.

In step 405, the document management server 100 copies the decrypted predetermined document to the decryption folder, and advances the processing to step 406.
In step 406, the document management server 100 determines whether a file with the extension “.success” or a file with the extension “.error” exists, and the file with the extension “.success” also has the extension “ If neither of the “.error” file exists, the process proceeds to step 440.

  In step 440, an error log file indicating that the process has ended abnormally is output, and the process proceeds to step 441. In step 441, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display a timeout error screen (G206 in FIG. 10), and the client 200 uses the received screen information to output a timeout error screen. (G206 in FIG. 10) is displayed, and the process proceeds to step 433. In step 433, the client 200 transmits a message indicating that the “return” button is pressed on the timeout error screen to the document management server 100, and the document management server 100 detects that the “return” button is pressed. Is received, the process proceeds to step 410. In step 410, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display a list screen (G200 in FIG. 9), and the client 200 uses the received screen information to display a list screen ( This process is terminated by displaying G200) in FIG.

  On the other hand, if there is either a file with the extension “.success” or a file with the extension “.error”, the process proceeds to step 407. In step 407, the document management server 100 proceeds to step 408 if there is a file with the extension “.success”, and proceeds to step 430 if there is a file with the extension “.error”. Proceed.

  In step 408, the document management server 100 deletes the file with the extension “.success” and advances the process to step 409. In step 409, the document management server 100 stores the decrypted document file in a predetermined folder, and registers bibliographic information in the document management DB. When the extension is “.error” in step 407, the contents of the file with the extension “.error” are stored in the work area of the RAM 203 and the file with the extension “.error” is deleted in step 430. Then, the process proceeds to step 431. In step 431, an error log file is output using the error contents stored in the work area of the RAM 203, and the process proceeds to step 432.

  In step 432, the document management server 100 transmits to the client 200 screen information for causing the client 200 to display an error screen (G207 in FIG. 10), and the client 200 uses the received screen information to display an error screen (FIG. 10G207) is displayed, and the process proceeds to step 433. In step 433, the client 200 sends a message to the document management server 100 indicating that the “return” button on this error screen has been pressed or the “return” button on the timeout screen has been detected, and the document management server 100 “returns”. When a message indicating that the button has been pressed is received, the process proceeds to step 410. In step 410, the document management server 100 transmits screen information for causing the client 200 to display a list screen (G200 in FIG. 9) to the client 200, and the client 200 uses the received screen information to display the list screen (FIG. 9 G200) is displayed and the process is terminated.

  Next, FIG. 7 is a diagram showing a detailed flow of the encrypted document browsing process of the client 200 in the encryption system of FIG. 3 of the document management system according to the embodiment of the present invention. First, in step 501, the client 200 attempts to establish a session with the document management server 100 and confirms the establishment of the session. If the session has not been established, the process ends. By assuming the establishment of a session as a premise for browsing, it is possible to prevent the decryption of a downloaded encrypted document in an environment where the session cannot be established, and to improve security. If the session can be established, the process proceeds to step 502.

  In step 502, the client 200 refers to the encryption key table of the document management server 100 based on the encryption key of the client, and ends the browsing process when the same encryption key does not exist. If it exists, the process proceeds to step S503. In step 503, address information for each page (start address and end address for each page) acquired from the header information of the document and the set number of pages are stored in the work area of the RAM 203, and the encrypted data of the first page of the document is stored. Is decrypted and stored in the work area of the RAM 203, the first page of the decrypted document is displayed on the screen, and the process proceeds to step 504.

  In step 504, the client 200 performs a decryption process (prefetch decryption process) for the next page currently displayed using the address information and encryption key for each page acquired from the header information of the encrypted document. The document data thus decrypted is stored in the work area of the RAM 203, and the process proceeds to step 505.

  In step 505, the client 200 confirms the session with the document management server 100 again. When the session is not established, re-establishment of the session is attempted, and when the session is not established, the process is terminated. If a session has been established, the process proceeds to step 506. In step 506, has the client 200 designated a page on the page designation input screen (G300 in FIG. 11) (whether the GO button has been pressed after a number has been entered in the page entry field of the screen in FIG. 11)? Judging. When the page is designated, the process proceeds to step 507. If no page is designated, the process proceeds to step 509. In step 507, the number of pages requested is calculated based on the current number of pages stored in the work area of the RAM 203 and whether the previous page button or the next page button is detected. The designated page is decrypted using the address information for each page of the encrypted document stored in the work area of the RAM 203, stored in the work area of the RAM 203, and the process proceeds to Step 508. In step 508, the corresponding page of the decrypted document stored in the work area of the RAM 203 is displayed on the CRT 210, and the decrypted document data of pages other than the pages before and after the currently displayed page are displayed. Delete from the area and proceed to step 509.

  In step 509, it is determined whether or not the next page display is specified (whether the previous page button is pressed or the next page button is detected on the screen of FIG. 11). If the next page display is designated, the process proceeds to step 510. In step 510, the next page of the decrypted document that has been pre-read decrypted in step 504 and stored in the work area of the RAM 203 is displayed, and the table of contents and the data of the decrypted document of the pages other than the previous and subsequent pages currently displayed are displayed. Is deleted from the work area of the RAM 203 and the process proceeds to step 511.

  In step 511, confirmation of document browsing completion is performed. When it is detected that the end button is pressed, all the decrypted document data stored in the work area of the RAM 203 is erased (zero is written to the whole) and when no end button is detected. Return processing to 504 and return to decryption processing for the next page currently displayed. This page designation input and browsing end can always be interrupted by pressing the button on the screen on which buttons for instructing these are displayed, and processing according to the instruction can be executed.

  As described above, in the browsing process of FIG. 7, it is possible to browse only when a session is established by checking the establishment of a session in a timely manner, and the document is decrypted and displayed on a page-by-page basis. Since the decrypted document data other than the current page is deleted from the work area of the RAM 203, high security can be ensured while suppressing a decrease in the display response of the browsing display.

[Other Examples]
The functions shown in the flowcharts of FIGS. 6 to 9 and the screens of FIGS. 11 and 12 in this embodiment may be performed by a host computer by a program installed from the outside. In this case, the present invention is applied even when an information group including a program is supplied to the output device from a recording medium such as a CD-ROM, a flash memory, or an FD, or from an external recording medium via a network. Is.

  As described above, a recording medium in which a program code of software for realizing the functions of the above-described embodiments is recorded is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus is stored in the recording medium. It goes without saying that the object of the present invention can also be achieved by reading and executing the program code.

  In this case, the program code itself read from the recording medium realizes the novel function of the present invention, and the recording medium storing the program code constitutes the present invention.

  As a recording medium for supplying the program code, for example, a flexible disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, DVD-ROM, magnetic tape, nonvolatile memory card, ROM, EEPROM, A silicon disk or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) or the like running on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Furthermore, after the program code read from the recording medium is written in a memory provided in a function expansion board inserted in the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the case where the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

  Further, the present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or apparatus. In this case, by reading a recording medium storing a program represented by software for achieving the present invention into the system or apparatus, the system or apparatus can enjoy the effects of the present invention.

  Furthermore, by downloading and reading out a program represented by software for achieving the present invention from a server, database, etc. on a network using a communication program, the system or apparatus can enjoy the effects of the present invention. It becomes.

It is a figure which shows the system configuration | structure of the document management system of this invention. It is a figure which shows the hardware constitutions of the document management server and client of this invention. It is a flowchart which shows the encryption process of embodiment of this invention. It is a flowchart which shows the decoding process of embodiment of this invention. It is a figure which shows the detailed processing flow of the encryption system of embodiment of this invention. It is a figure which shows the detailed processing flow of the decoding system of embodiment of this invention. It is a figure which shows the detailed processing flow of the browsing process of the encrypted document of embodiment of this invention. It is a figure which shows the list display screen of a search result of a document, and the screen of an encryption process. It is a figure which shows the document selection screen of the decoding process of a document. It is a figure which shows the display screen in the process of decoding of a document, and the screen at the time of error occurrence. It is a figure which shows the page designation | designated screen in a document browsing process. It is a figure which shows the example of an item of document management DB. It is a figure which shows the example of an item of a user master. It is a figure which shows the example of an item of an organization master. It is a figure which shows the example of an item of a document management master.

Explanation of symbols

100 document management server 200 client 201 CPU
202 ROM
203 RAM
204 System Bus 205 Input Controller 206 Video Controller 207 Memory Controller 208 Communication I / F Controller 209 Keyboard 201 CRT
211 External memory (hard disk, etc.)
300 Communication line

Claims (13)

A document management system configured to allow communication between a document server and a browsing terminal,
The document server
Document storage means for storing documents to be managed;
Browsing request receiving means for receiving a document browsing request from the browsing terminal;
In accordance with the browsing request received by the browsing request receiving unit , the divided encryption unit that divides the document requested to be browsed and encrypts it using encryption information ;
Document sending means for sending the encrypted document to the viewing terminal that sent the viewing request,
The browsing terminal is
Browsing request transmission means for transmitting a document browsing request to the document server;
In response to the browsing request transmitted by the browsing request transmission unit, an encrypted document storage unit that receives and stores the divided and encrypted document from the document server;
Page designation means for designating a desired browsing page of the stored divided and encrypted document;
It said desired viewing page previous SL page specifying means specified, the first decoding means for decoding using the encrypted information,
A document management system comprising page display means for displaying a page decrypted by the first decryption means . The browsing terminal is
A determination unit for determining whether or not communication with the document management server is established;
The first decryption unit decrypts the divided and encrypted document when the determination unit determines that communication with the document management server is established, and the determination unit does not establish the communication. 2. The document management system according to claim 1, wherein when the determination is made, the divided and encrypted document is not decrypted. The browsing terminal is
A second decoding means for decoding the next divided page of the desired browsing page designated by the page designation means;
The second decrypting means decrypts and stores a divided page next to the page displayed by the page display means when the page designating means displays the desired browsing page. the document management system according to claim 1 or claim 2. The document server
A calculation means for calculating capacity information for each divided and encrypted document ;
Adding means for adding the capacity information to the encrypted information;
Further comprising
The document management system according to claim 1 to claim 3 wherein the document transmission unit and transmits the encrypted information including the volume information to the viewing terminal. The browsing terminal is
A deletion unit that deletes the decrypted document stored in the storage unit;
The deletion unit deletes a decrypted and stored document that is not a browsing page displayed by the page display unit and pages before and after the decrypted browsing page from the storage unit. The document management system according to claim 1. A document management system viewing terminal configured to allow communication between the document server and the viewing terminal,
Browsing request transmission means for transmitting a document browsing request to the document server;
And respond to the browsing request transmitted by the viewing request transmitting unit, and the encrypted document storage means for receiving and storing the encrypted document from the document server is divided,
Page designation means for designating a desired browsing page of the stored divided and encrypted document;
It said desired viewing page previous SL page specifying means specified, the first decoding means for decoding using the encrypted information,
A browsing terminal comprising: a page display means for displaying a page decrypted by the first decryption means . The browsing terminal is
A determination unit for determining whether or not communication with the document management server is established;
The first decryption unit decrypts the divided and encrypted document when the determination unit determines that communication with the document management server is established, and the determination unit does not establish the communication. The browsing terminal according to claim 6, wherein when it is determined, the divided and encrypted document is not decrypted. The browsing terminal is
A second decoding means for decoding the next divided page of the desired browsing page designated by the page designation means;
The second decrypting means decrypts and stores a divided page next to the page displayed by the page display means when the page designating means displays the desired browsing page. viewing terminal according to claim 6 or claim 7. The browsing terminal is
A deletion unit that deletes the decrypted document stored in the storage unit;
The deletion unit deletes a decrypted and stored document that is not a browsing page displayed by the page display unit and pages before and after the decrypted browsing page from the storage unit. The browsing terminal according to claims 6 to 8. A control method of a document management system configured to allow communication between a document server having a document storage means for storing a document to be managed and a browsing terminal,
The browsing request receiving means of the document server receives a browsing request for a document from the browsing terminal ;
Dividing the encryption means of the document server, in response to said view request receiving step wherein the viewing request is received, dividing the browsing requested document, and split encryption step of encrypting using the encryption information,
A document transmission step in which the document transmission means of the document server transmits the encrypted document to the browsing terminal that has transmitted the browsing request ;
The browsing request transmission means of the browsing terminal transmits a browsing request for a document to the document server,
Encrypted document storage means of the viewing terminal, the browse request transmitting step in response to the browsing request transmitted in the divided and encrypted document storage process for receiving and storing the encrypted document from the document server When,
A page designating step for designating a desired viewing page of the divided and encrypted document stored in the encrypted document storing step by the page designating unit of the browsing terminal ;
First decoding means of the viewing terminal, the desired viewing pages the page specifying means has specified a first decoding step of decoding using the encrypted information,
A page display step in which the page display means of the browsing terminal displays the page decoded by the first decoding step;
A control method characterized by comprising . A method for controlling a browsing terminal of a document management system configured to be able to communicate with a document server having a document storage means for storing a document to be managed and the browsing terminal,
The browsing request transmission means of the browsing terminal transmits a browsing request for a document to the document server,
An encrypted document storage step in which the encrypted document storage means of the browsing terminal receives and stores the divided and encrypted document from the document server in response to the browsing request transmitted in the browsing request transmission step. When,
A page designating step for designating a desired viewing page of the divided and encrypted document stored in the encrypted document storing step by the page designating unit of the browsing terminal;
A first decryption step in which a first decryption unit of the browsing terminal decrypts the desired browse page designated by the page designation unit using the encryption information;
A page display step in which the page display means of the browsing terminal displays the page decoded by the first decoding step;
A control method characterized by comprising. A program that can be read and executed by a document management system configured to allow communication between a document server and a browsing terminal,
The document server,
Document storage means for storing documents to be managed;
Browsing request receiving means for receiving a document browsing request from the browsing terminal;
In accordance with the browsing request received by the browsing request receiving unit , the divided encryption unit that divides the document requested to be browsed and encrypts it using encryption information ;
Document transmitting means for transmitting the encrypted document to the browsing terminal that transmitted the browsing request ;
To function,
The browsing terminal is
Browsing request transmission means for transmitting a document browsing request to the document server;
In response to the browsing request transmitted by the browsing request transmission unit, an encrypted document storage unit that receives and stores the divided and encrypted document from the document server;
Page designation means for designating a desired browsing page of the stored divided and encrypted document;
It said desired viewing page previous SL page specifying means specified, the first decoding means for decoding using the encrypted information,
Page display means for displaying the page decrypted by the first decryption means ;
Features and to Help program that is to function. A program that can be read and executed by a viewing terminal of a document management system configured to allow communication between a document server and a viewing terminal,
The browsing terminal is
Browsing request transmission means for transmitting a document browsing request to the document server;
In response to the browsing request transmitted by the browsing request transmission unit, an encrypted document storage unit that receives and stores the divided and encrypted document from the document server;
Page designation means for designating a desired browsing page of the stored divided and encrypted document;
It said desired viewing page previous SL page specifying means specified, the first decoding means for decoding using the encrypted information,
Page display means for displaying the page decrypted by the first decryption means ;
Features and to Help program that is to function.

Images