JP2006080785A - Electronic filing document browsing system, its server, client, program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent secondary circulation even in unauthorized browsing and lighten a network load. <P>SOLUTION: A saver 13 stores an open document (cipher text) 13b prepared up by ciphering an open document (clear text) and its deciphering key. A publisher 14 acquires all open documents (cipher text) 13b presently browsable from the saver 13 to sends them to a request side personal computer 20. With respect to a browsing request of any document, the publisher acquires a deciphering key corresponding to the requested document from the saver 13 to send it to the request side personal computer 20. The personal computer 20 deciphers the already received cipher texts 13b to clear texts using the deciphering key, and only displays them but is blocked from performing the saving, editing, printing, etc. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic document browsing system.

  Conventionally, various electronic documents have been released on the Internet, for example. For example, if an electronic document is stored in an arbitrary server and accessed via a network (Internet) or the like, some electronic documents can be browsed freely. For example, users such as IDs and passwords Some use authentication to limit who can view an electronic document. In addition, by setting a publication deadline and using a calendar / clock function of a computer (such as a Web server) that stores the electronic document, browsing of the electronic document that has passed the publication deadline is also restricted.

  However, if authentication information such as an ID or password is leaked due to some reason, the electronic document may be illegally distributed, and the distributed document may be easily distributed over a wide area and viewed by anyone. There is a risk of secondary distribution.

To deal with this problem, Patent Document 1 describes that when an electronic document obtained by digitizing an attached document such as an operation manual is changed, it can be easily read by a legitimate user and read by a person other than the legitimate user. There is disclosed a technique for preventing the electronic document from being distributed and distributing the electronic document easily and safely through the Internet.
Japanese Patent Laid-Open No. 2003-6028

  In the above-mentioned Patent Document 1, access authority (including expiration date) for an electronic document stored in an electronic document management apparatus is managed, and a document reading tool in a user's computer does not have a document editing function and a storage function. Therefore, a mechanism for preventing the distributed electronic document from being saved / edited is proposed. As a result, even if an electronic document is illegally acquired and displayed, the distributed document can be easily distributed over a wide area and viewed by anyone (known to an unspecified number of third parties; Secondary distribution) can be avoided. However, on the other hand, if the same electronic document is to be browsed again and again, it is necessary to access the electronic document management device and perform electronic document acquisition (distribution) operations such as downloading. For this reason, especially when the capacity of the electronic document is large, the network load increases and the download waiting time also increases.

  An object of the present invention is to prevent secondary distribution even if an electronic document is illegally browsed in an electronic document browsing system for browsing an electronic document via a network, and the encrypted electronic document is transferred to the user terminal side. It is to provide an electronic document browsing system, a program, and the like that reduce network load / download time by distributing and distributing a corresponding decryption key each time an arbitrary electronic document is browsed.

  The electronic document browsing system of the present invention is an electronic document browsing system having a server that publishes one or more arbitrary electronic documents on a network, and a client that browses the electronic document via the network. Encrypted electronic document storing means for encrypting and storing an electronic document, and each time an electronic document issuance request is received from an arbitrary client, one or more stored in the encrypted electronic document for the requesting client The public document issuing means for transmitting the encrypted electronic document and the browsing request for any encrypted electronic document among the encrypted electronic documents transmitted from the arbitrary client to the client are requested. Decryption key issuing means for transmitting a decryption key corresponding to the encrypted electronic document to the requesting client, wherein the client Request issuing means for transmitting the electronic document issuance request or the browsing request to the server, electronic document storage means for storing one or more encrypted electronic documents sent by the public document issuing means, and the public document An operation unit that causes an arbitrary browsing target to be selected from the encrypted electronic document stored in the storage unit and causes the request issuing unit to transmit the browsing request of the selected browsing target; and the request issuance processing unit Using the decryption key sent from the decryption key issuing means in response to the browse request, the encrypted electronic document to be browsed is decrypted and displayed, and after the decryption, the decrypted key and the decrypted electronic document are displayed. Decryption / display means that does not store the document is provided.

  Conventionally, in order to prevent secondary distribution even if an electronic document is illegally viewed, the access authority (including the expiration date) to the electronic document stored in the electronic document management apparatus is managed. Because the document reading tool on the user's computer does not have the document editing function and the storage function, the distributed electronic document is not stored / edited. For this reason, the same electronic document is viewed many times. Whenever you wanted to, you had to download an electronic document. On the other hand, in the system of the present invention, for example, all electronic documents that are currently viewable due to, for example, a viewing expiration date are downloaded to the client side. However, this electronic document is encrypted, and a decryption key is required to view the contents. Therefore, when the client wants to view an arbitrary electronic document, it downloads the decryption key corresponding to the electronic document, but the decrypted electronic document (plain text) can only be displayed and is not saved. I am doing so. Also, the decryption key is not saved.

  Thus, even if the electronic document is illegally browsed, secondary distribution can be prevented, and even when it is desired to browse the same electronic document many times, it is only necessary to download the decryption key. Usually, since the decryption key has a smaller amount of data than an electronic document, the network load and the download waiting time can be significantly reduced as compared with the conventional case.

  Further, in the electronic document browsing system, for example, the electronic document storage means stores an encryption stored for decryption by the decryption / display means only when the request issuing means transmits the browsing request. The reading of the digitized electronic document may be permitted.

  Also, in the electronic document browsing system, for example, in the server, each encrypted electronic document is set with an arbitrary browsing expiration date, and the public document issuing means transmits it to the authentication request source client. Encrypted electronic documents are all encrypted electronic documents that are within the expiry date, and the decryption key issuing means has passed the expiry date of the encrypted electronic document to be viewed at the time of the viewing request The decryption key may not be issued.

  Further, in the electronic document browsing system, for example, in the server, each encrypted electronic document is set to be viewable or not, and even if it is within the view expiration date, The encrypted electronic document or the decryption key may not be transmitted to the client. For example, when any problem occurs, for example, when it is detected that there has been an illegal browsing, the system can easily cope with it by simply changing the setting of whether or not browsing is possible.

  Note that the present invention is not limited to the electronic document browsing system described above, and can be configured as a server itself and a client itself constituting the system, a program itself for realizing the functions of the server and the client by a computer, or It can also be configured as a recording medium itself recording this program.

  According to the electronic document browsing system, the program, and the like of the present invention, in the electronic document browsing system for browsing an electronic document via a network, it is possible to prevent secondary distribution even if the electronic document is illegally browsed and to be encrypted. By distributing the electronic document to the user terminal side and distributing the corresponding decryption key each time an arbitrary electronic document is browsed, the network load can be reduced / download time can be reduced.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram of the electronic document browsing system of this example.
An electronic document browsing system 1 shown in FIG. 1 includes a server 10 on the electronic document publishing side and a personal computer 20 (client) of an arbitrary user on the electronic document browsing side connected to a network 2 to each other. The data can be sent and received. In addition, the personal computer 20 exists not only for one unit but for each arbitrary user.

The server 10 includes a registration unit 11, an authentication unit 12, a storage unit 13, and an issue unit 14.
The personal computer 20 includes an operation unit 21, a request issue unit 22, a document display unit 23, a document storage unit 24, and a decryption unit 25.

  The functions and processes of the functional units from the registration unit 11 to the issue unit 14 and the operation unit 21 to the decryption unit 25 are stored in a storage device (hard disk or the like; not shown here) included in the server 10 and the personal computer 20. The predetermined application program is read / executed by a processing device (CPU or the like; not shown here). The same applies to the detailed configurations of these functional units shown in FIGS. In addition, the command / data transmission / reception between the server 10 and the personal computer 20 in the following description is naturally performed via the network 2 and will not be described step by step.

First, the configuration of the server 10 will be described.
The registration unit 11 causes the administrator of the server 10 or the like to register desired information (authentication information 12a and document information 13a (expiration date of a public document, etc.)) and store them in the authentication unit 12 and the storage unit 13. In addition, each time there is a new registration request for a public document (plain text) that is an arbitrary electronic document, the registration unit 11 has an encryption key (encryption key) and a decryption key (decryption key) corresponding to the public document to be newly registered. Key) is generated, and the public document (plain text) is encrypted using the encryption key to generate a public document (cipher text) 13b, which is stored in the storage unit 13. Also, the decryption key is stored in the storage unit 13. In this example, it is assumed that the encryption method is a secret key encryption method.

Whenever there is any request from the arbitrary personal computer 20 on the browsing side, the authentication unit 12 confirms the legitimacy of the user of the requesting personal computer 20 using the registered user information.
When the authenticating unit 12 confirms the validity of the user, the issuing unit 14, if the request is a public document issuing request, the public document (cipher text) 13 b stored in the storage unit 13. Basically, all public documents (ciphertext) that can be browsed at present are acquired from the storage unit 13 and transmitted to the requesting personal computer 20, and the request is a request for browsing any public document. First, the decryption key corresponding to the requested public document is acquired from the storage unit 13 and transmitted to the requesting personal computer 20.

Next, the configuration of the personal computer 20 will be described.
The operation unit 21 causes a user of the personal computer 20 to perform a desired input by operating, for example, a keyboard and a mouse.

The request issuance unit 22 transmits the public document issuance request and the public document browsing request to the server 10 in accordance with the content input from the user by the operation unit 21.
The document storage unit 24 stores the public document (cipher text) sent from the server 10 in response to the public document issuance request in the public document storage device 24a.

  When the decryption unit 25 receives a decryption key from the server 10 in response to the browsing request for the arbitrary public document, the decryption unit 25 acquires the public document (cipher text) requested to be browsed from the document storage unit 24, Decryption is performed using the decryption key to generate a public document (plain text), which is displayed on the document display unit 23.

  In the electronic document browsing system 1 configured as described above, when the user instructs acquisition of a public document from the operation unit 21 on an arbitrary personal computer 20 side at any time, the request issuance unit 22 sends a public document issuance request to the server 10. Send.

When a public document issuance request is sent from an arbitrary personal computer 20 side, the authentication unit 12 refers to the authentication information 12a to check the validity of the user.
When the authentication unit 12 confirms that the user is valid, the issuing unit 14 distributes the public document (cipher text) 13b stored in the storage unit 13 to the personal computer 20 side. At this time, the distributed public document (cipher text) 13b to be distributed is, for example, all currently viewable, but is not limited thereto.

  On the personal computer 20 side, the document storage unit 24 stores all downloaded public documents (ciphertext) 13b in the document storage unit 24. In this state, the contents of the public document cannot be browsed.

  Thereafter, at any time on any personal computer 20 on which the download has been completed, the user operates the operation unit 21 to select a desired public document from among the downloaded public documents, and to request the browsing , The request issuing unit 22 transmits a decryption key issue request regarding the desired public document to the server 20.

  In response to the request, the issuance unit 14 refers to the document information 13a of the storage unit 13 when the authentication unit 12 confirms that the user is valid, as described above. It is checked whether or not the public document that can be browsed is present, and if so, the decryption key of the requested public document is transmitted to the personal computer 20.

  As a result, the decryption unit 25 can decrypt the public document (encrypted text) 13b stored in the document storage unit 24 using the received decryption key, and the document display unit 23 can decrypt the public document. The contents can be displayed.

  Here, the personal computer 20 has a document reading tool that does not have an editing function or a storage function, as in the above-mentioned Patent Document 1, etc., so that illegal secondary distribution of electronic documents can be prevented. Thus, in the case of having a tool that prohibits the editing and storage of an electronic document in order to prevent illegal secondary distribution of the electronic document, in the conventional patent document 1 and the like, as described above, an electronic document that has already been viewed is once again. Even when viewing, the electronic document must be downloaded again from the server. In particular, when the capacity of the electronic document is large, there is a problem that the network load increases and the download waiting time also increases. On the other hand, in this method, as described above, public documents that can be browsed are downloaded together in advance in the form of ciphertext, and each time an electronic document is browsed, the decryption key only needs to be sent. Therefore, such a problem can be solved. In particular, when the capacity of the electronic document is large or when the same electronic document is browsed many times, a remarkable effect can be obtained.

As an example of a document reading tool that prohibits editing and saving, for example, Acrobat (and Adobe Reader for viewing only) of Adobe System (USA) for generating and browsing a PDF file is known. The following restrictions can be applied to a PDF electronic document generated using this Acrobat.
・ "Prohibit printing and editing of documents" using password security
"Prohibit storage of decrypted electronic document" using security based on digital ID (Although it is permitted to display the encrypted electronic document in plaintext using the decryption key, this plaintext electronic document Is forbidden to save)
Even in the personal computer 20 of this example, illegal secondary distribution of an electronic document can be prevented by using the above-described functions for prohibiting editing and saving. However, in the following detailed description, other examples will be shown and described. And

FIG. 2 shows a detailed configuration diagram of the server 10, and FIGS. 3 to 5 show a detailed configuration and operation of the personal computer 20. FIG.
Hereinafter, the electronic document browsing system 1 will be described in more detail with reference to FIGS.

First, referring to FIG. 2, a user registration process performed in advance or at any time will be described.
At the time of user registration, the registration unit 11 displays information (for example, illustrated) on the display or the like of the server 10 to authenticate the user to the administrator or the like of the server 10 by displaying the illustrated registration screen 61. The user ID and password are not limited to this example), but the user is allowed to set whether or not to permit viewing of the public document. Note that the user ID and password may be displayed by causing the user to input the user information input screen on the personal computer 20 and allowing the administrator of the server 10 to input only whether or not browsing is permitted. Of course, other user information such as the user's name and address may be input.

  The input / set user information is stored in a user information registration table 31 held by the authentication unit 12. As shown in the figure, the user information registration table 31 stores, for each user, whether or not browsing is possible in association with the user ID and password. Note that the case of “No” for browsing refers to, for example, the case where the system discloses bid information or the case where the user loses the bid qualification. Of course, it goes without saying that it is not limited to such an example.

Next, with reference to FIG. 2, a public document registration process executed for registering a new electronic document every time a new electronic document is generated will be described.
When the registration unit 11 receives a new public document (plain text) and is instructed to register it, the registration unit 11 first displays the document registration screen 62 shown in FIG. A person or the like is allowed to set the browsing expiration date (browsing start date and browsing end date) of the public document and whether or not browsing is possible. Here, as to whether browsing is permitted or not, basically, “permitted” is set during the registration process. After that, there is a case where the browsing is reset to “No” for some reason. Some reason is, for example, suspension of publication of an old document accompanying document version upgrade or the like. Or, for example, when it is discovered that a public document has been illegally browsed, it is possible to inhibit secondary distribution by prohibiting browsing thereafter.

  Further, the key information generation unit 64 in the registration unit 11 generates a key (a pair of an encryption key and a decryption key) to be used for the new public document, and the encryption processing unit 65 uses the encryption key to generate the new disclosure. By encrypting the document (plain text), a public document (cipher text) 13b is generated and stored in the database (document registration apparatus) of the storage unit 13. Then, the document information generation unit 63 uses the storage destination information (storage address, URL, link information, etc.) and the generated decryption key together with the information set and input on the document registration screen 62 (these various types). The information corresponds to the document information 13a) and is stored in the document information registration table 41 of the storage unit 13.

Next, in FIG. 2, processing / function when there is a public document issue request or a decryption key issue request from an arbitrary personal computer 20 side will be described.
The issuing unit 14 includes a request reception processing unit 51, a decryption key issuing unit 52, and a public document issuing unit 53.

  When receiving the public document issuance request or the decryption key issuance request, the request reception processing unit 51 requests the authentication unit 12 to confirm the validity of the user. Of course, these requests include the user ID and password of the user of the requesting personal computer 20. The authentication unit 12 determines the legitimacy of the user based on whether or not these user ID and password are registered in the user information registration table 31. Further, referring to the browsing availability information in the user information registration table 31, it is confirmed whether browsing is possible or not. If the user is valid and browsing is “permitted”, it is determined that the use is permitted, and the determination result is returned to the request reception processing unit 51.

If the authentication unit 12 determines that the use is permitted, the request reception processing unit 51 issues an issuance instruction to the decryption key issuing unit 52 or the public document issuing unit 53 in response to any of the above requests.
When the published document issuing unit 53 receives the issuing instruction, the published document issuing unit 53 refers to the document information registration table 41 and obtains all published documents that are currently viewable. For example, all the public documents whose current date and time are within the expiration date (between the browsing start date and the browsing end date) and whose browsing permission of the table 41 is “possible” are obtained. Then, a public document (ciphertext) file is acquired from the storage location (URL or the like) of each obtained public document, and these public document (ciphertext) files are transmitted to the personal computer 10.

  The above description is an example, and the present invention is not limited to this example. For example, the request reception processing unit 51 registers the document information when the user is valid and whether or not the table 31 is viewable. Referring to the table 41, all the public documents whose current date and time are within the expiration date (between the browsing start date and the browsing end date) and whose browsing permission is “possible” are extracted, and their storage locations (URL etc.) Or the document name may be notified to the personal computer 10. In this case, the personal computer 10 requests the issuing unit 14 to download the public document (encrypted text) using the notified storage location (URL, etc.) and document name, thereby opening the public document (encrypted text) file. Will get.

  Upon receipt of the issuance instruction, the decryption key issuing unit 52 refers to the document information registration table 41 of the storage unit 13 and the public document requested to be browsed is currently viewable (currently within the expiry date and If it is confirmed that browsing is “permitted”, the decryption key is returned to the personal computer 20. Of course, when browsing is impossible, the fact is notified to the personal computer 20 side.

Next, the detailed configuration of the personal computer 20 shown in FIG. 3 will be described.
In FIG. 3, the operation unit 21 first includes a “public document acquisition” button and a browsed document selection column displayed on the display of the personal computer 20 and a keyboard / mouse that allows the user to specify these buttons and options. Composed.

The request issuing unit 22 issues a request corresponding to the operation content of the operation unit 21 to the request reception processing unit 51 of the server 10 and notifies the document storage unit 24 that the request has been made.
The document storage unit 24 includes a public document storage device 24a that stores a public document (ciphertext) sent from the server 10, and inputs the received public document (ciphertext) and stores it in the public document storage device 24a. And an output process of outputting the public document requested to be browsed in the public document (cipher text) stored in the public document storage device 24a to the document decrypting unit 25. However, these input processing and output processing are performed only when there is a notification from the request issuing unit 22 that the request has been made. As a result, only the encrypted public document can be stored. In addition, the stored public document (cipher text) can be output to the outside only when browsing (when receiving the decryption key).

  The document decryption unit 25 decrypts the public document (encrypted text) output (read) from the document storage unit 24 at the time of browsing by using the decryption key sent from the server 10, so that the public document ( Plaintext). However, the document decryption unit 25 uses the generated public document (plain text) only for display by the document display unit 23 so that file output and storage cannot be performed. Also, after decryption, the decryption key is immediately deleted. Therefore, if it is desired to view the same electronic document again after the display is completed, it is necessary to request the server 10 again to obtain the same decryption key.

  The document display unit 23 (and the document decryption unit 25) is a dedicated viewer for displaying the decrypted public document (plain text). The document display unit 23 has only a document display (browsing) function, and does not have an editing / printing function or a file output / saving function.

FIG. 4 shows the flow of processing related to obtaining a public document, and FIG. 5 shows the flow of processing during browsing.
First, the acquisition (downloading) process of the public document (ciphertext) 13b will be described with reference to FIG. As already briefly described, the electronic document browsing system of this example is based on the premise that secondary distribution is prevented, but the public document (ciphertext) 13b is stored in the personal computer 20 on the user side. Every time the document is browsed, a decryption key is obtained. As a result, even when it is desired to browse a public document once browsed, it is not necessary to download from the server 10 one by one, and the network load can be reduced.

  In this example, in order to reduce time and effort, the public document (ciphertext) 13b is distributed in a batch (regardless of whether or not all of the documents are actually viewed). Even if 13b is stored in the personal computer 20 on the user side, the contents cannot be viewed without the decryption key, so there is no problem). Conversely, in order to avoid downloading a document that is not viewed, any electronic When a document browsing request is made, if the document has already been downloaded, only the decryption key may be distributed. If not, the electronic document may be distributed, and then the decryption key may be distributed.

  In the acquisition (download) process of the public document (cipher text) 13b, first, in FIG. Is operated ((a) shown in FIG. 4). At that time, user authentication information (in this example, user ID and password) is also input. In response to this operation, the request issuing unit 22 transmits a public document acquisition request together with user authentication information to the issuing unit 14 of the server 10 (b). Further, it notifies the document storage unit 24 that a public document acquisition request has been issued (outputs a received document storage instruction) (c). The user ID and password may be input by the user each time or may be registered in advance.

Upon receiving this public document acquisition request, the issuing unit 14 of the server 10 in FIG. 2 transmits, for example, all publicly available public documents (ciphertexts) to the personal computer 20 by the above-described processing.
When the public document (ciphertext) is received on the personal computer 20 side (d), only when the document storage unit 24 receives the notification (instruction), the input process is executed, and the received public document (encryption) is received. (Sentence) are all stored in the public document storage device 24a (e).

  Then, the document storage unit 24 causes the operation unit 21 to display the file name and the like of each public document (ciphertext) stored in the public document storage device 24a (f). As a result, a list of file names of these public documents is displayed in the browse document selection field of the operation unit 21.

  If the authentication unit 12 determines that the user is not valid, or if the browsing permission is “No”, the request reception processing unit 51 browses the request issuing unit 22 of the personal computer 10. Send rejection notice. The request issuing unit 22 that has received the browsing refusal notification displays, for example, a message “Document browsing authority is not granted” on the document display unit 23.

  A plurality of public documents (ciphertexts) 13b are stored in the user's personal computer 20 by the acquisition (download) process of the public document (ciphertext) 13b described above. A corresponding decryption key is required for each public document. Hereinafter, the browsing process of a public document will be described with reference to FIG.

  First, by the acquisition (download) process of the public document (ciphertext) 13b described above, the operation unit 21 of the user's personal computer 20 displays the download in the browse document selection column as shown in FIGS. The file name of each published document (ciphertext) is displayed.

  In this state, at any time, the user selects and inputs the file name of the public document to be browsed from the operation unit 21 ((g) shown in FIG. 5). The request issuing unit 22 transmits a decryption key issuance request corresponding to the selected public document to the server 20 together with the user authentication information (h). Further, a browsing document output instruction is issued to the document storage unit 24 (i). In response to this instruction, the document storage unit 24 extracts the public document (cipher text) to be browsed from the public document storage device 24a and outputs it to the document decryption unit 25 (j).

  On the other hand, the issuing unit 14 of the server 10 that has received the request for issuing the decryption key returns a decryption key corresponding to the public document requested to be browsed to the personal computer 20 by the above-described processing. Receive and pass to the document decryption unit 25 (k).

  Thereby, the document decryption unit 25 generates a public document (plain text) by decrypting the output public document (cipher text) using the decryption key, and displays the contents on the document display unit 23. . Thus, the user can know the contents of the public document. However, as described above, storage, editing, printing, and the like cannot be performed, and the decryption key is immediately discarded, so that illegal secondary distribution can be prevented. Since only the decryption key is transmitted at the time of browsing, particularly when it is necessary to browse the same document many times, it is possible to reduce the network load and the download time.

  In addition, if you want to prohibit browsing of a specific user for any reason in the server 10 on the public side, or if you want to prohibit browsing of any public document for all users, register user information Browsing can be easily prohibited simply by changing the browsing permission setting in the table 31 and the document information registration table 41 to “No”.

FIG. 6 is a hardware configuration diagram of a computer such as the server 10 or the personal computer 20.
A computer 100 shown in the figure includes a CPU 101, a memory 102, an input unit 103, an output unit 104, a storage unit 105, a recording medium drive unit 106, and a network connection unit 107, which are connected to a bus 108. It has become. The configuration shown in the figure is an example, and the present invention is not limited to this.

The CPU 101 is a central processing unit that controls the entire computer 100.
The memory 102 is a memory such as a RAM that temporarily stores a program or data stored in the storage unit 105 (or the portable recording medium 109) during program execution, data update, or the like. The CPU 101 executes the various functions / processes described above (functions / processes of the functional units shown in FIGS. 1 to 3) using the program / data read out to the memory 102.

The output unit 104 is, for example, a display.
The input unit 103 is, for example, a keyboard or a mouse.
The network connection unit 107 is configured to connect to a network such as an intranet or the Internet and perform command / data transmission / reception with other information processing apparatuses.

  The storage unit 105 is, for example, a hard disk or the like, and a predetermined application program or various types for causing the CPU 101 to execute the various processes and functions described above (functions and processes of the functional units illustrated in FIGS. 1 to 3). Data (such as data in the table shown in FIG. 2) is stored.

  Alternatively, these programs / data may be stored in the portable recording medium 109. In this case, the program / data stored in the portable recording medium 109 is read by the recording medium driving unit 106. The portable recording medium 109 is, for example, an FD (flexible disk) 109a, a CD-ROM 109b, a DVD, a magneto-optical disk, or the like.

  Alternatively, the program / data may be downloaded from another apparatus via a network connected by the network connection unit 107. Or you may download further what was memorize | stored in the other external apparatus via the internet.

  In addition, the present invention can be configured not only as a portable storage medium recording a program for realizing the various processes of the present invention on a computer, but also as the program itself.

It is a schematic block diagram of an electronic document browsing system. It is a detailed block diagram of the server of FIG. It is a detailed block diagram of the personal computer of FIG. It is a figure which shows a public document acquisition process procedure. It is a figure which shows a decoding key acquisition process procedure. It is a computer hardware block diagram.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Network 10 Server 11 Registration part 12 Authentication part 13 Storage part 14 Issue part 20 Personal computer 21 Operation part 22 Request / decryption part 23 Document display part 31 User information registration table 32 Authentication information collation part 41 Document information registration table 51 Request reception process Unit 52 decryption key issuing unit 53 public document issuing unit 61 registration screen 62 document registration screen 63 document information generating unit 64 key information generating unit 65 encryption processing unit 100 computer 101 CPU
DESCRIPTION OF SYMBOLS 102 Memory 103 Input part 104 Output part 105 Storage part 106 Recording medium drive part 107 Network connection part 108 Bus 109 Portable recording medium 109a FD (flexible disk)
109b CD-ROM

Claims (8)

In an electronic document browsing system having a server that publishes any one or more electronic documents on a network and a client that browses the electronic documents via the network,
The server
Encrypted electronic document storage means for encrypting and storing the electronic document;
Public document issuing means for transmitting one or more encrypted electronic documents stored in the encrypted electronic document to the requesting client each time an electronic document issuance request is received from an arbitrary client;
Each time there is a request to view an arbitrary encrypted electronic document among the encrypted electronic documents transmitted from the arbitrary client to the client, a decryption key corresponding to the encrypted electronic document requested to be viewed is assigned to the request source. Decryption key issuing means for transmitting to the client of
The client
Request issuing means for transmitting the electronic document issuing request or the browsing request to the server;
Electronic document storage means for storing one or more encrypted electronic documents sent by the public document issuing means;
An operation unit that causes an arbitrary browsing target to be selected from the encrypted electronic document stored in the public document storage unit, and that the request issuing unit transmits the browsing request of the selected browsing target;
Using the decryption key sent from the decryption key issuing means in response to the browsing request by the request issuing processing means, the encrypted electronic document to be browsed is decrypted and displayed, and after the decryption, the decryption A decryption / display means that does not store the key and the decrypted electronic document;
An electronic document browsing system comprising:   The electronic document storage means permits reading of the stored encrypted electronic document for decryption by the decryption / display means only when the request issuing means transmits the browsing request. The electronic document browsing system according to claim 1.   In the server, each encrypted electronic document has an arbitrary viewing expiration date, and the encrypted document sent by the public document issuing means to the authentication requesting client is within the viewing expiration date. And the decryption key issuing means does not issue the decryption key when the browsing request time of the encrypted electronic document to be browsed has passed. The electronic document browsing system according to claim 1.   In the server, whether or not browsing is set for each encrypted electronic document, and if the browsing is not permitted even within the browsing validity period, the encrypted electronic document or the decryption key 3. The electronic document browsing system according to claim 2, wherein transmission to the client is not performed. In the server in an electronic document browsing system having a server that publishes any one or more electronic documents on a network and a client that browses the electronic documents via the network,
Encrypted electronic document storage means for encrypting and storing the electronic document;
Public document issuing means for transmitting one or more encrypted electronic documents stored in the encrypted electronic document to the requesting client each time an electronic document issuance request is received from an arbitrary client;
Each time there is a request to view an arbitrary encrypted electronic document among the encrypted electronic documents transmitted from the arbitrary client to the client, a decryption key corresponding to the encrypted electronic document requested to be viewed is assigned to the request source. A decryption key issuing means for transmitting to the client of
The server characterized by having. In the client in the electronic document browsing system, comprising: a server that publishes any one or more electronic documents on a network; and a client that browses the electronic document via the network.
Request issuing means for transmitting an electronic document issuing request or a browsing request to the server;
Electronic document storage means for storing one or more encrypted electronic documents sent from the server in response to the electronic document issuance request;
An operation unit that causes an arbitrary browsing target to be selected from the encrypted electronic document stored in the public document storage unit, and that the request issuing unit transmits the browsing request of the selected browsing target;
Using the decryption key sent from the server in response to the browse request by the request issuing processing means, the encrypted electronic document to be browsed is decrypted and displayed, and after the decryption, the decryption key and the decryption key are decrypted. Decryption / display means that does not store the digitized electronic document;
A client characterized by comprising: A computer that publishes any one or more electronic documents on a network and a computer that is the server in the electronic document browsing system having a client that browses the electronic documents via the network;
A function of encrypting and storing the electronic document;
A function of transmitting one or more encrypted electronic documents stored in the encrypted electronic document to the requesting client each time an electronic document issuance request is received from an arbitrary client;
Each time there is a request to view an arbitrary encrypted electronic document among the encrypted electronic documents transmitted from the arbitrary client to the client, a decryption key corresponding to the encrypted electronic document requested to be viewed is assigned to the request source. The ability to send to other clients,
A program to realize A computer that publishes any one or more electronic documents on a network and a computer that is the client in the electronic document browsing system including a client that browses the electronic documents via the network;
A function of transmitting an electronic document issuance request to the server;
A function of storing one or more encrypted electronic documents sent from the server in response to the electronic document issuance request;
A function for selecting an arbitrary browsing target from the stored encrypted electronic document and transmitting a browsing request for the selected browsing target to the server;
Using the decryption key sent from the server in response to the viewing request, the encrypted electronic document to be viewed is decrypted and displayed, and after the decryption, the decrypted key and the decrypted electronic document are displayed. The function not to save,
A program to realize

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