JP2001155007A - Synchronizing system for data base, data transmitting/ receiving system and electronic perusal system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the introduction of an electronic perusal system under an open network environment. SOLUTION: A document file transmitted from a slave server 20 (second device) in a step S4 is preserved in a master data base DB1 (first data base) and updated by a master server 10 (first device) and afterwards, that document file is transmitted as differential data while using an SMTP protocol capable of passing firewall system 10b and 20b. This document file is preserved in a mirror data base DB2(second data base) and updated by the slave server 20 (second device) and the contents of the respective data bases are matched. Therefore, the setting change of the firewall system is unnecessary and the introduction of the electronic reference system is promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a database synchronization system for promoting the introduction of an electronic browsing system in an open network environment, a data transmission / reception system for preventing information leakage, and a promotion of introduction in an open network environment. The present invention relates to an electronic browsing system that aims to prevent information leakage and an electronic browsing system that aims to prevent information leakage.

[0002]

2. Description of the Related Art Conventionally, in a company or the like, various types of document information on a corporate LAN (Local Area Network) are centrally managed, and a system that allows many employees to access the document information (hereinafter, referred to as a system). Electronic browsing system)
Has been introduced to share information.

[0003] This type of electronic browsing system stores document files in a document database and centrally manages document information. However, since security of document information is regarded as important, as described above, it is difficult for a company to use it. It is often introduced into a relatively closed network environment such as an internal LAN.

[0004] In a company or the like in which a LAN is constructed for each of a plurality of offices, the offices are often connected via the Internet. Then, even under such an open network environment, an electronic browsing system has been gradually introduced.

In this case, a document database is provided separately for each LAN of the business office, and the following information processing is performed. That is, when a new document file is created, the electronic browsing system uses the document file to update, for example, a document database serving as a master, and sequentially transmits the document file to each LAN via the Internet. Control is performed so that the contents of each document database are the same. That is, control is performed so that the contents are always synchronized between the distributed document databases.

By the way, a firewall is usually provided at the connection point between the LAN and the Internet for the purpose of preventing intrusion of unauthorized information.
Information transmitted to the N side is restricted. Specifically, the firewall device restricts the passage of data depending on the type of communication protocol.

Therefore, when introducing the electronic browsing system, the settings of the firewall device are appropriately changed by the network administrator so that the document file can pass through the firewall device.

[0008]

However, since the setting work of a firewall device is generally complicated, an electronic browsing system for distributing, arranging and synchronizing a document database and controlling the same in an open network environment including the Internet or the like has been proposed. There is a situation that is difficult to be introduced to. In particular, companies that do not have a skilled network administrator tend to hesitate to introduce an electronic browsing system for such reasons.

On the other hand, since the security of document information is regarded as important, when it is transmitted via the Internet, it is necessary to reliably prevent the leakage of the document information.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a database synchronization system which promotes the introduction of an electronic browsing system into an open network environment, and a data synchronization system. It is an object of the present invention to provide a data transmission / reception system for preventing leakage, an electronic browsing system for promoting introduction into an open network environment, and an electronic browsing system for preventing leakage of information.

[0011]

In order to solve the above-mentioned conventional problems, a database synchronization system according to claim 1 of the present invention is provided with a firewall device for restricting the passage of data according to the type of a communication protocol. When at least a first database and a second database are provided on one side and the other side of the firewall device, respectively, in a synchronization system for synchronizing these databases, the first database and the second database are synchronized. Is updated, the difference generated by this update is used as difference data, and the difference data is received via the first device that sends out the communication device using a communication protocol that can pass through the firewall device and the firewall device. The second database is updated using the difference data and the first data is updated. And having a second device and to match the base and the contents of the second database.

According to the first aspect of the present invention, when the first device updates the data in the first database, the first device uses the difference generated by the update as difference data, and The packet is transmitted using a communication protocol that can pass through the firewall device. Then, the second device receives the difference data transmitted by the first device via the firewall device, updates the second database using the received difference data, and updates the first database and the second database. The contents of the second database are matched.
Therefore, when introducing the electronic browsing system in an open network environment including the Internet or the like, it is not necessary to change the settings of the firewall device.

[0013] A database synchronization system according to a second aspect of the present invention is the synchronization system according to the first aspect,
When the second device receives a database update request, the second device uses data for updating the database as update request data, and transmits the update request data to a communication protocol that can pass through the firewall device. And the first device is configured to update the first database using update request data received via the firewall device. It is characterized by having.

[0014] In the present invention according to claim 2, the first device uses the update request data once transmitted from the second device to perform, for example, comparison of data content or date. Updating the first database after performing the processing accompanying the updating of the database allows the second database to be updated.
In this device, the processing accompanying these updates is unnecessary, and as a result, the processing load on the second device is reduced.

According to a third aspect of the present invention, in the synchronous system according to the first or second aspect, the difference data or the update request data is SM.
It is characterized by being configured to be transmitted and received by the TP protocol.

According to the third aspect of the present invention, the database can be synchronized via the Internet by using the SMTP protocol used for electronic mail transmission on the Internet as a communication protocol.

According to a fourth aspect of the present invention, in the data transmission / reception system wherein the data transmitted from the first device is received by the second device, the first device includes First key information storage means for storing a plurality of keys and identification information of each key; dividing means for dividing input data; and keys corresponding to the number of divisions divided by the dividing means. 1 key information storage means as appropriate, encrypts each of the divided data using these selected keys, and identifies each key used for the encryption with respect to each of the encrypted data. , And transmitting means for transmitting each data output from the encrypting means, wherein the second device transmits the data stored in the first key information storing means. Multiple keys for Key information storage means for storing a key for decryption and identification information stored in the first key information storage means, and each data sent from the transmission means of the first device. Receiving means for receiving the key information, collating the identification information added to each data received by the receiving means with the identification information stored in the second key information storage means, Decryption means for identifying keys for decryption, and decrypting each data encrypted by the encryption means of the first apparatus using the identified keys; and decryption by the decryption means. And synthesizing means for synthesizing each of the converted data.

In the present invention according to claim 4, the encryption means of the first device selects keys corresponding to the number of divisions from the first key information storage means, and uses these selected keys. Then, each divided data is encrypted, and identification information of each key used for the encryption is added to each of the encrypted data.

On the other hand, the decryption means of the second device compares the identification information added to each received data with the identification information stored in the second key information storage means and compares the identification information with the number of divisions. A key for decryption is specified, and each data is decrypted using the specified key.

As described above, since identification information is added to each encrypted data, it is easy to specify a key for decryption, but it is difficult to decrypt data by a third party. Therefore, it is possible to easily prevent information leakage.

Preferably, the encryption means has a function of randomly selecting a key for encryption, thereby making decryption more difficult and preventing information leakage more reliably.

[0022] In the electronic browsing system according to the fifth aspect of the present invention, when a firewall device for restricting the passage of data according to the type of communication protocol is provided, one side and the other side of the firewall device are respectively provided. In an electronic browsing system in which at least a first database and a second database are arranged to allow browsing of the contents of the respective databases, when data is updated in the first database, the data generated by the update is generated. The first device sends the difference data as the difference data using a communication protocol that can pass through the firewall device, and the second database uses the difference data received through the firewall device. Update the contents of the first database and the second database to match And having a second device.

According to the fifth aspect of the present invention, there is provided an electronic browsing system which does not require setting change of a firewall device when introducing the system.

An electronic browsing system according to a sixth aspect of the present invention is the electronic browsing system in which data for browsing transmitted from the first device is received by the second device. Key information storage means for storing a plurality of keys for conversion and identification information of each of the keys, a dividing means for dividing the input data, and a number of divisions by the dividing means. A key is appropriately selected from the first key information storage means, each of the divided data is encrypted using the selected key, and each of the encrypted data is used for the encryption. An encryption unit for adding and outputting key identification information; and a transmission unit for transmitting each data output from the encryption unit. The second device stores the first key information storage unit in the first key information storage unit. Multiple keys for stored encryption A second key information storage unit in which a corresponding key for decryption and identification information stored in the first key information storage unit are stored, and a second key information storage unit transmitted from the transmission unit of the first device. Receiving means for receiving data, and comparing the identification information added to each data received by the receiving means with the identification information stored in the second key information storage means, by comparing the number of divisions Decryption means for identifying keys for decrypting the data, and using these identified keys to decrypt each data encrypted by the encryption means of the first device; and Synthesizing means for synthesizing each of the decoded data.

According to the sixth aspect of the present invention, there is provided an electronic browsing system capable of preventing information leakage when transmitting a document file or the like.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a database synchronization system, a data transmission / reception system and an electronic browsing system according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of an electronic browsing system to which the first embodiment of the present invention is applied.
It shows an example of introduction to a company where a LAN is configured in each business office.

In FIG. 1, LAN1 and LAN2 are interconnected via the Internet 50. LA
In N1, a master server 10 as a first device and a plurality of client devices 100 connected to the master server 10 are configured. On the other hand, the LAN 2 includes a slave server 20 as a second device and a plurality of client devices 200 connected to the slave server 20. The master server 10 and the slave server 20 constitute a database synchronization system or a data transmission / reception system according to the present invention.

A storage device 10a is connected to the master server 10, and stores a document database (hereinafter, referred to as a master database DB1). Master database DB
1 stores a document file and an attribute file having the attribute thereof.

On the other hand, the slave server 20 has a storage device 2
0a is connected. Here is a mirror database DB
2 is configured and controlled so that its contents are the same as those of the master database DB1. Master database DB
1. The mirror database DB2 constitutes a first database and a second database, respectively. The storage device 20a of the slave server 20 is provided with a temporary storage area for temporarily storing information transmitted from each client device 200.

Each of the servers 10 and 20 executes a process according to a request from a client device. That is, a document file or the like created by each client device is registered and updated in the document database, and controls such as file deletion and file name change are performed.

Each server 10, 20 has the function of a web server, while each client device 100,
200 has a web browser for browsing information in the document database. That is, each server can appropriately provide information in the document database to each client device in response to a request, and the client device can browse the information.

At the connection point between the LAN 1 and the Internet 50, a firewall device 10b for restricting the passage of data according to the type of communication protocol is installed. Similarly, a firewall device 20b is installed at a connection point between the LAN 2 and the Internet 50.

Each firewall device 10b, 20b
As is generally done, the SMTP (Simple M
ail Transfer Protocol).

Note that the electronic browsing system of the present embodiment
There are other LAN3, LAN4, etc., not shown in FIG. 1, which have the same configuration as LAN2. That is, the other LAN3, LAN4, etc. are provided with slave servers 30, 40, etc., having the same configuration as the slave server 20, and each slave server is connected to storage devices 30a, 40a, etc.

FIG. 2 is a block diagram showing a part of the configuration of the master server and the slave server. FIG. 2 shows a part for performing transmission processing and reception processing.

The master server 10 and each slave server include an input / output interface unit 11, a file division unit 1
2, a key information storage unit 13, an encryption unit 14, a communication unit 15, a decryption unit 16, and a file synthesis unit 17.

The input / output interface unit 11 controls the input and output of information to and from the storage device, reads information from the storage device to the file division unit 12, and reads the information from the storage device.
To write information to the storage device.

The file dividing section 12 is a section that divides the file read by the input / output interface section 11 and adds information for combining to each divided file.

The key information storage unit 13 stores a plurality of keys for performing encryption and decryption, and each key is provided with its identification information. This key information storage unit 13
It corresponds to the first key information storage means or the second key information storage means. Note that a key for encryption and a key for decryption may be separately provided.

The encryption unit 14 uses the key stored in the key information storage unit 13 to encrypt each of the files divided by the file division unit 12, and stores key identification information in each of the encrypted files. Add.

The communication section 15 sends each file (referred to as a transfer file) encrypted by the encryption section 14 and further added with key identification information to the Internet 50. At this time, the SMTP protocol is used as a communication protocol.

The communication section 15 receives a file transmitted by the SMTP protocol from another LAN 2 or the like and outputs the file to the decoding section 16. The communication unit 15 constitutes a transmitting unit and a receiving unit.

The decryption unit 16 decrypts the file output from the communication unit 15 using the key stored in the key information storage unit 13.

The file combining unit 17 combines the files decrypted by the decrypting unit 16 and restores the original registered file.

As described above, the input / output interface unit 11 controls input / output to / from the storage device and stores the restored registration file in the document database (master database DB1 or mirror database DB2).

FIG. 3 is a diagram showing the structure of the document database. As shown in FIG. 3, the document database has a hierarchical structure, and an item name for pre-dividing information is provided in the uppermost layer. The second layer stores documents or comments belonging to the respective items (here, questions and opinions regarding the contents of the documents, and in the case where the documents are questionnaires, their responses are included). In the third layer, an answer to each comment (comment answer) and the like are stored. Such information is called document information, and a unique number is assigned to the document information. These unique numbers are associated with each other and systematically managed by the master server 10.

For this reason, the user of the electronic browsing system
By operating the client device, all information related to the document information can be accessed from any document information in the document database. As a result, a plurality of users can share document information on the system. For example, it becomes easy to grasp the details of the discussion, and at the same time, it contributes to accumulation of know-how.

Next, processing in the electronic browsing system according to the present embodiment will be described. First, an outline of the processing will be described with reference to FIG. Each arrow in FIG. 1 indicates a flow of information, and reference numerals S1 to S5 attached to each arrow indicate processing steps. Here, it is assumed that the master database DB1 and the mirror database DB2 are already synchronized.

For example, the client device 20 of the LAN 2
Suppose that a new document file is created at 0.
This file may be any of the above-mentioned document, comment, or comment answer. Client device 20
0 is an input module previously transmitted from the slave server 20 (specifically, HTML (Hyper Text Markup Lan)
guage) file, which is programmed so that attribute information can be input when it is read by a web browser. ), The attribute information of the document file input by the user is transmitted to the slave server 20 together with the newly created document file (step S).
1).

Next, the slave server 20 checks an error in the transmitted attribute information according to a predetermined format, and transmits the result to the client device 200 (step S2). The client device 200 transmits the attribute information corrected by the user to the result of the transmitted check to the slave server 20 again, and the slave server 20 stores the document file and the attribute information in the storage device 2.
0a is stored in the temporary storage area (step S3). still,
If there is no error in the attribute information, processing after transmission of the check result is not performed.

Here, the attribute information is an item name on the document database, a related file name, a registrant name, or the like, and is predetermined according to the specifications of the electronic browsing system.

Next, the slave server 20 stores the storage device 2
The document file and the attribute information once stored in the temporary storage area of the master server 1 via the Internet 50 are stored in the master server 1.
0, and the master server 10 transmits this to the storage device 10a.
Is updated in the master database DB1 (step S4). At that time, for example, processing accompanying the update of the database such as comparison of data contents or dates is performed.

Then, the master server 10 stores the storage device 1
0a is transmitted to the slave server 20 in reverse, and the slave server 20 stores and updates the information in the mirror database DB2 of the storage device 20a (step S).
5).

That is, the slave server 20 is configured to temporarily transmit data for updating the database to the master server 10 as update request data when the slave server 20 requests a database update. The server 10 is configured to update the master database DB1 using the update request data.

Therefore, in the present embodiment, the slave server 20 does not need to perform the above-described processing associated with the update, and as a result, the processing load on the slave server 20 can be reduced.

Next, the processing of steps S4 and S5 will be described in more detail with reference to FIGS.

FIG. 4 shows LAN1, LAN2 and LAN3.
It is a sequence diagram which shows the flow of mutual information. The document file (registered file f1) for which registration has been requested from the client device 200 is transmitted to the master server 10 by the slave server 20. This registration file f
Reference numeral 1 denotes update request data.

Here, the processing at the time of file transmission by the slave server 20 will be specifically described with reference to FIG.

First, the file dividing section 12 divides the registered file f1 into A1, A2 and A3, for example. Then, division information is added to each of the divided files (hereinafter, referred to as division files). The division information is information for performing file synthesis later, and usually includes the order in the original file. Here, it is assumed that the file is divided into three as shown in the figure, and division information "1/3", "2/3" and "3/3" are added to each divided file.

Next, the encryption unit 14 encrypts each divided file to which the division information has been added. At this time, the encryption unit 14 randomly selects keys for the number of divisions from the key information storage unit 13 and encrypts each divided file with the selected keys. Here, it is assumed that the keys 001k, 005k, and 060k have been selected and encrypted, and the files generated by the encryption are X1, X2, and X3 (hereinafter, these files are referred to as encrypted files).

Next, the encryption unit 14 sets the key 001k, 00
ID information ID001 and ID corresponding to 5k and 060k
005 and ID060 are stored in encrypted files X1, X2, X
3 respectively. The files generated in this way are referred to as transfer files f10, f20, and f30.

Then, the communication unit 15 uses the SMTP as a communication protocol to transfer each of the transfer files f10, f20, f3.
0 is transmitted to the Internet 50. At this time,
The master server 10 is specified as the transmission destination. Since the SMTP protocol is a communication protocol that can pass through the firewall devices 20b and 10b, each transmitted transfer file reaches the master server 10.

Next, as shown in FIG. 4, the master server 10 receives and restores each transfer file and restores it to the storage device 10a.
To save.

Here, the processing when the master server 10 receives a file will be specifically described with reference to FIG.

The communication section 15 receives each of the transfer files f10, f20, f30 transmitted by the SMTP protocol and outputs the transfer files f10, f20, f30 to the decoding section 16.

The decryption unit 16 transmits the transfer file f10,2
0, 30 to identification information ID001, ID005 and ID
060 is removed, and the encrypted files X1, X2, X3 are cut out. Then, the identification information added to each transfer file is compared with the identification information stored in the key information storage unit 13 to determine the number of keys (keys 001k, 005k, 06) corresponding to the number of divisions.
0k) is specified, and each of the encrypted files X1, X2, X3 is decrypted using the specified key.

Subsequently, the file synthesizing unit 17 divides each of the decrypted files into division information “1/3”, “2/3”
And “3/3” are removed, and the divided files A1, A2,
Cut out A3. Then, it analyzes the division information, combines the cut-out files, and restores the original registered file. 4 and 5, the registration file restored on the master server 10 is denoted by reference numeral f2.

Then, the input / output interface unit 11
The file restored by the file synthesizing unit 17 is stored in the master database DB1 of the storage device 10a.

As described above, since each transfer file transferred on the Internet is encrypted with the key selected at random and the identification information is added, it is easy for the receiving side to specify the key for decryption. On the other hand, decryption by a third party becomes more difficult, and thus leakage of information can be easily prevented.

Once the registration file f2 is stored and the master database DB1 is updated, the master server 10 transfers the registration file f2 to the slave servers 20, 30 as differential data. At this time, the master server 10 performs the above-described division and encryption. Then, the generated transfer files f11, 21, 31 are transferred to the slave servers 20, 30 via the Internet 50. The SMTP protocol is also used for the communication protocol at this time.

The transfer files f11, 21, 31 transmitted from the master server 10 are stored in the slave servers 20, 3, respectively.
0, and are decoded and registered as files f3 and f4. Then, the mirror database stored in the storage devices 20a and 30a is updated, and the contents of the master database and the mirror database match.

In the above description, a document file for which registration has been applied has been taken as an example. However, even if control information such as document attribute information or file deletion is used, as long as information is transmitted between LANs, SMTP can be used. Protocol is used. on the other hand,
HTTP (Hyper Text Transf) for browsing information on LAN
er Protocol) protocol is used.

In this embodiment, the master database and the mirror database are distinguished from each other so that the former is updated before the latter is updated. However, it is not always necessary to update the database in a predetermined order. For example, priority may be given to updating the database in the LAN where the file is created.

The communication protocol of the present invention is SMTP
The present invention is not limited to this, and may be changed as appropriate in accordance with the settings of the firewall device. The transmission timing of the information between the servers does not necessarily have to be at the time of file registration application, and the transmitting server may autonomously perform the transmission. Therefore, for example, file transmission may be performed when the transmission side server is lightly loaded.

[0076]

As described above, according to the first aspect of the present invention,
According to the database synchronization system according to the first aspect of the present invention, the contents of the database are matched by using the first device that sends the difference data using the communication protocol that can pass through the firewall device and the difference data received through the firewall device. Since the second device is provided, the database can be synchronized without changing the settings of the firewall device, and therefore, introduction of the electronic browsing system into an open network environment is promoted.

According to the database synchronization system of the second aspect of the present invention, the first device updates the first database using the update request data once transmitted from the second device. In addition, the processing associated with the update in the second device is not required, and the burden is reduced.

According to the database synchronization system of the third aspect of the present invention, the database can be synchronized via the Internet by using the SMTP protocol.

According to the data transmission / reception system according to the fourth aspect of the present invention, by adding identification information to each encrypted data, it is easy to specify the key for decryption. This makes it difficult for the user to decrypt the data, so that it is possible to easily prevent information leakage.

According to the electronic browsing system according to the fifth aspect of the present invention, it is possible to provide an electronic browsing system which does not require a change in the setting of the firewall device when introducing the system.

According to the electronic browsing system according to the sixth aspect of the present invention, it is possible to provide an electronic browsing system capable of preventing information leakage when transmitting a document file or the like.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of an electronic browsing system to which a first embodiment of the present invention has been applied.

FIG. 2 is a block diagram showing a part of a configuration of a master server and a slave server.

FIG. 3 is a diagram showing a structure of a document database.

FIG. 4 is a sequence diagram showing a flow of information between LANs.

FIG. 5A is a diagram illustrating a process at the time of file transmission, and FIG. 5B is a diagram illustrating a process at the time of file reception.

[Explanation of symbols]

 1, 2, 3 LAN (Local Area Network) 10 Master server 10a, 20a, 30a Storage device 10b, 20b Firewall device 11 Input / output interface unit 12 File division unit 13 Key information storage unit 14 Encryption unit 15 Communication unit 16 Decryption Unit 17 File synthesis unit 20, 30 Slave server 100, 200 Client device DB1 Master database (document database) DB2 Mirror database (document database)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masuko Okada 1-9-1, Konan, Minato-ku, Tokyo NTT Communicationware Co., Ltd. (72) Inventor Yuji Ohata Konan, Minato-ku, Tokyo 1-9-1-1 NTT Communicationware Co., Ltd. F-term within the company (reference) 5B045 BB42 DD17 GG01 5B082 GA04 GA14 GB02 5B085 AE13 AE29 BG07 CA04 5B089 GA11 HA10 HB07 JA12 JB22 KA06 KA17 KB13 KC57 KH30

Claims (6)

[Claims] 1. A firewall device for restricting the passage of data according to the type of communication protocol is provided, and a first side is provided on one side and a first side is provided on the other side of the firewall device.
When at least a database and a second database are provided, a synchronization system for synchronizing each of the databases is provided. When data is updated in the first database, a difference generated by the update is compared with the difference. A first device that sends out the difference data using a communication protocol that can pass through the firewall device, and updates the second database using the difference data received through the firewall device. A database synchronization system, comprising: a second device for matching contents of a first database and a second database. 2. When the second device receives a database update request, the second device sets data for updating the database as update request data, and transmits the update request data to the firewall device. The first device is configured to transmit to the first device once using a communicable communication protocol, and the first device updates the first database using update request data received through the firewall device. 2. The database synchronization system according to claim 1, wherein the database synchronization system is configured to perform the following operations. 3. The method according to claim 1, wherein the difference data or the update request data is S
The database synchronization system according to claim 1 or 2, wherein the system is configured to be transmitted and received by an MTP protocol. 4. The data transmitted from the first device is transmitted to a second device.
In the data transmission / reception system receiving by the device, the first device comprises: first key information storage means for storing a plurality of keys for encryption and identification information of each of the keys; And a key for the number of divisions divided by the division means.
From the key information storage means, and encrypts each of the divided data using these selected keys, and identifies the identification information of each key used for the encryption with respect to each of the encrypted data. An encryption unit for adding and outputting, and a transmission unit for sending out each data output from the encryption unit, wherein the second device is configured to encrypt the data stored in the first key information storage unit. A second key information storage unit in which a key for decryption corresponding to a plurality of keys for identification and identification information stored in the first key information storage unit are stored; Receiving means for receiving each data sent from the transmitting means; identifying information added to each data received by the receiving means; and identifying information stored in the second key information storing means. Check and decode for the number of divisions A decryption means for identifying a key and decrypting each data encrypted by the encryption means of the first device using the identified keys; and a data decryption means for decrypting the data by the decryption means. And a combining means for combining the data. 5. When a firewall device that restricts the passage of data according to the type of communication protocol is provided, a first database and a second database are provided on one side and the other side of the firewall device, respectively. In an electronic browsing system capable of browsing the contents of each database at least, when data is updated in the first database, a difference caused by the update is set as difference data, and the difference data is A first device that transmits using a communication protocol that can pass through the firewall device; and a second database that is updated by using difference data received through the firewall device to update the first database and the second database. And a second device for matching the contents of the database. Browsing system. 6. An electronic browsing system in which data for browsing transmitted from a first device is received by a second device, wherein the first device includes a plurality of keys for encryption and each of these keys. First key information storage means for storing the identification information of the first key, division means for dividing the input data, and keys corresponding to the number of divisions divided by the division means.
From the key information storage means, and encrypts each of the divided data using these selected keys, and identifies the identification information of each key used for the encryption with respect to each of the encrypted data. An encryption unit for adding and outputting, and a transmission unit for sending out each data output from the encryption unit, wherein the second device is configured to encrypt the data stored in the first key information storage unit. A second key information storage unit in which a key for decryption corresponding to a plurality of keys for identification and identification information stored in the first key information storage unit are stored; Receiving means for receiving each data transmitted from the transmitting means; identifying information added to each data received by the receiving means and identification information stored in the second key information storing means; Check and decrypt for the number of divisions Identify key, using these identified key, the first
An electronic browsing system comprising: a decryption unit that decrypts each data encrypted by the encryption unit of the device; and a combining unit that combines the data decrypted by the decryption unit.