JP2008187608A - Data transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent leakage of information in transmission of data between computers. <P>SOLUTION: In a data transmission system, a transmission client computer generates encryption data and key data for restoring the encryption data, transmits the encryption data to a reception client computer, and transmits the key data to a server computer, and the server computer receives the key data from the transmission client computer, then notifies the reception client computer about the reception, transmits the key data to the reception client computer after there is a request from the reception client computer, and notifies the transmission client computer about the transmission. The reception client computer restores the encryption data using the key data received from the server computer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data transmission system for transmitting data between a transmission client computer and a reception client computer via a server computer.

  In recent years, with the spread of electronic communication networks represented by the Internet, data is frequently transmitted between computers.

  In the transmission of data between computers, if the data to be transmitted is transmitted in the same format, the transmitted data may be leaked in the middle.

  Therefore, the data to be transmitted on the transmission source computer is encrypted before transmission to generate encrypted data and key data for restoring the encrypted data, and the encrypted data and the key data are transmitted separately. A data transmission system configured to restore encrypted data using key data on a transmission destination computer has been considered (see, for example, Patent Document 1).

JP 2006-180110 A

  However, in the above conventional data transmission system, since the encrypted data and the key data are directly transmitted from the transmission source computer to the transmission destination computer, the encrypted data and the key data are obtained illegally in the middle. If so, the encrypted data could be restored using the key data, and there was a risk of data leakage.

  Further, in the conventional data transmission system, when data is transmitted to a plurality of transmission destinations, each time data is transmitted, encrypted data is created as key data, and the encrypted data and key data are respectively transmitted. Since the data must be transmitted separately, the data transmission work has been complicated.

  Therefore, in the present invention according to claim 1, in the data transmission system for transmitting data between the transmission client computer and the reception client computer via the server computer, the transmission client computer encrypts the data to be transmitted, Encrypted data and key data for restoring the encrypted data are generated, the encrypted data is transmitted to the receiving client computer, the key data is transmitted to the server computer, and the server computer receives the key from the transmitting client computer. After receiving the data, the receiving client computer is notified, and after receiving a request from the receiving client computer, the key data is transmitted to the receiving client computer, and the transmitting client computer is notified and received. Client computer was to restore the encrypted data using the key data received from the server computer.

  Further, in the present invention according to claim 2, in the present invention according to claim 1, the server computer receives key data from the transmission client computer when a plurality of reception client computers are designated from the transmission client computer. After that, each receiving client computer is notified, and after receiving a request from each receiving client computer, the key data is transmitted to the receiving client computer and notified to the transmitting client computer.

  Also, in the present invention according to claim 3, in the present invention according to claim 1 or 2, the transmission client computer extracts a part of data to be transmitted, and the extracted part of the data is digital watermarked. We decided to generate key data by embedding it in an image file using processing.

  And in this invention, there exists an effect described below.

  That is, in the present invention, the server computer notifies the reception client computer after receiving the key data from the transmission client computer, and then transmits the key data only when there is a request from the reception client computer. The key data can be prevented from being illegally obtained by a third party.

  In addition, since the server computer sends the key data to the sending client computer and notifies the sending client computer, the data sender can confirm that the key data has been sent to the sending client computer. , The reliability of the data transmission system can be improved.

  In particular, when data is transmitted to a plurality of transmission client computers, only one key data need be transmitted to the server computer, and the data transmission can be simplified.

  If key data is generated by extracting part of the data to be transmitted and embedding the extracted part of the data in an image file using digital watermark processing, the key data is generated by performing digital watermark processing. The processing time for doing so can be shortened.

  Hereinafter, specific contents of the data transmission system according to the present invention will be described with reference to the drawings.

  The data transmission system according to the present invention transmits data between a transmission client computer and a reception client computer via a server computer. The hardware configuration is schematically shown in FIG. Is schematically shown in FIG.

  As shown in FIG. 1, in a data transmission system according to the present invention, a server computer 1, a transmission client computer 2, and reception client computers 3 and 4 are connected by an electronic communication network 5 so as to communicate with each other.

  As shown in FIG. 2, when transmitting data from the transmission client computer 2 to the reception client computers 3 and 4, first, data transmitted by the sender using the transmission client computer 2 is encrypted.

  In the encryption of the data to be transmitted, it is only necessary to generate encrypted data obtained by encrypting the data to be transmitted and key data for restoring the encrypted data, and various existing programs are used. Can do. The encrypted data includes data that cannot be opened unless a password is entered, and the key data in that case is a password.

  Also, in data encryption, a dedicated data encryption program that generates key data by extracting a part of the data and embedding the extracted part of the data in an image file using digital watermark processing is used. Also good. The specific contents of this data encryption program will be described later.

  Next, as shown in FIGS. 2 and 3, the transmission client computer 2 transmits the generated encrypted data to the reception client computers 3 and 4, respectively. The encrypted data may be transmitted by attaching the encrypted data to a normal mail, or may be transmitted via the server computer 1.

  The encrypted data is stored in each of the receiving client computers 3 and 4 by transmitting the encrypted data.

  Next, as shown in FIGS. 2 and 3, the transmission client computer 2 transmits the generated key data only to the server computer 1. If there are a plurality of receiving client computers 3 and 4, the receiving client computer 3 and 4 are designated from the sending client computer 2 to the server computer 1.

  By transmitting the key data, the server computer 1 stores the key data.

  Next, as shown in FIGS. 2 and 4, the server computer 1 notifies the reception client computers 3 and 4 designated by the transmission client computer 2 that the key data has been received from the transmission client computer 2. .

  Next, as shown in FIGS. 2 and 5 (or FIG. 6), the reception client computer 3 (4) requests the server computer 1 to transmit key data.

  In response to the request from the receiving client computer 3 (4), the server computer 1 transmits key data to the receiving client computer 3 (4). Thereafter, the server computer 1 notifies the sending client computer 2 that the key data has been sent to the receiving client computer 3 (4).

  By transmitting the key data, the receiving client computer 3 (4) stores the key data, and the encrypted data can be restored using the key data.

  As described above, in the data transmission system, the transmission client computer 2 encrypts data to be transmitted, generates encrypted data and key data for restoring the encrypted data, and encrypts the data. The data is transmitted to the receiving client computers 3 and 4, the key data is transmitted to the server computer 1, and the server computer 1 notifies the receiving client computers 3 and 4 after receiving the key data from the transmitting client computer 2. After receiving a request from the computers 3 and 4, the key data is transmitted to the receiving client computers 3 and 4 and notified to the transmitting client computer 2, and the receiving client computer encrypts the data using the key data received from the server computer 1. To restore data It is.

  In the above data transmission system, when the server computer 1 designates a plurality of reception client computers 3 and 4 from the transmission client computer 2, each of the reception client computers 3, 3 after receiving key data from the transmission client computer 2. 4, the key data is transmitted to the receiving client computers 3 and 4 after a request from each receiving client computer 3 and 4, and the transmitting client computer 2 is notified.

  As described above, in the data transmission system, when the server computer 1 receives the key data from the transmission client computer 2 and notifies the reception client computers 3 and 4 and then receives a request from the reception client computer 3 and 4. Since only the key data is transmitted, it is possible to prevent the key data from being illegally obtained by a third party.

  In addition, in the above data transmission system, the server computer 1 sends the key data to the transmission client computer 2 and then notifies the transmission client computers 3 and 4 so that the sender of the data is sent to the transmission client computers 3 and 4. Thus, it is possible to confirm that the key data has been transmitted, and to improve the reliability of the data transmission system.

  Next, the contents of the data encryption program used in the data transmission system will be described.

  The data encryption program is for causing a computer to execute a process of encrypting data by embedding data in an image file using digital watermark processing, and a flowchart thereof is shown in FIG. The flow of processing is schematically shown in FIG.

  As shown in FIG. 7, the data encryption program 6 first executes an initial setting step S1 for initial setting of the computer.

  In this initial setting step S1, a work area in the computer is secured, and connection confirmation of a storage medium for finally storing the encrypted file is performed.

  Next, the data encryption program 6 executes an encrypted data designation step S2 for receiving designation of data to be encrypted from the user.

  In this encrypted data designation step S2, a path name and file name indicating the storage location of one or more data to be encrypted are received from the user, and the path name and file name are stored. Note that the path name and file name of the data to be encrypted may be key-input by the user, or may be selected by the user from a file group displayed in a tree on the monitor.

  Next, the data encryption program 6 executes an original data reading step S3 for reading data designated by the user as original data 7 into a predetermined storage area.

  In this original data reading step S3, based on the path name and file name stored in the encrypted data specifying step S2, all of the data is read into the storage area as the original data 7. If a plurality of data is specified in the encrypted data specifying step S2, all the data are read into the storage area as the original data 7, 7 ′.

  Next, the data encryption program 6 executes a concealment processing step S4 for concealing the original data 7 read in the original data reading step S3.

  In this concealment processing step S4, concealment processing set in advance is applied to the original data 7 to generate concealment data 8. For example, the order of the data array of the original data 7 may be changed in units of several bits or several bytes, or may be encrypted based on predetermined key data. In short, it is sufficient that the original data 7 cannot be recognized. Here, when a plurality of data is specified in the encrypted data specifying step S2, the concealment process is performed on all the original data 7, 7 ′, and the plurality of the concealed data 8, 8 ′ is obtained. Generate.

  Next, the data encryption program 6 executes a partial extraction step S5 for extracting a part of the concealed data 8 generated in the concealment processing step S4.

  In this partial extraction step S5, only the data of the preset position and number are extracted from the concealment data 8 generated in the concealment processing step S4 and stored as partial data 9. For example, 10-byte data from the beginning of the concealment data 8 is extracted as the partial data 9. Here, when a plurality of data is designated in the encrypted data designation step S2, partial data 9, 9 ′ are extracted from all the concealed data 8, 8 ′, respectively.

  Next, the data encryption program 6 combines all the partial data 9, 9 ′ extracted in the partial extraction step S5 when a plurality of data is specified in the encrypted data specification step S2. Step S6 is executed.

  In this coalescence processing step S6, all the partial data 9, 9 ′ are merged into one merged data 10 which is made continuous in a predetermined order.

  Next, the data encryption program 6 executes an image file selection step S7 for selecting the image files 11, 11 ′, 11 ″ used for digital watermark processing.

  In this image file selection step S 7, a plurality of image files 11, 11 ′, 11 ”having different sizes are stored in advance in a predetermined storage medium 12, and partial data 9 (encrypted data designation step) to which digital watermark processing is performed A plurality of image files 11, 11 ′, 11 according to the size of the combined data 10 (when a plurality of data is specified at the encrypted data specifying step S2) or when only one data is specified at S2. One image file 11 ′ (11, 11 ”) is selected from“.

  Next, the data encryption program 6 executes a digital watermark embedding process step S8 for performing a digital watermark process using the image file 11 ′ (11, 11 ″) selected in the image file selection step S7.

  In this digital watermark embedding processing step S8, when only one data is designated in the encrypted data designation step S2, the partial data 9 is selected in the image file 11 ′ (11, 11) selected in the image file selection step S7. The embedded image file 13 is generated by embedding in “) by digital watermark processing, and if a plurality of data is designated in the encrypted data designation step S2, all partial data 9, 9 ′ are merged. The embedded image file 13 is generated by embedding the merged data 10 in the image file 11 ′ (11, 11 ″) selected in the image file selection step S7 by digital watermark processing.

  In this way, in the data encryption program 6, if all of the original data 7 to be encrypted is embedded in the image file 11 ′ (11, 11 ″) using the digital watermark process, the digital watermark embedding process in step S8 is performed. Since the processing time becomes long and there is a problem in practical use, only the partial data 9 obtained by extracting a part of the original data 7 to be encrypted is embedded in the image file 11 ′ (11, 11 ″) using the digital watermark processing. Thus, the processing time in the digital watermark embedding process step S8 can be shortened.

  Moreover, in the data encryption program 6, when there are a plurality of original data 7 and 7 'to be encrypted, the electronic data is extracted from the partial data 9, 9' extracted from each of the original data 7, 7 '. If the watermark processing is performed, the processing time in the digital watermark embedding processing step S8 becomes longer. Therefore, the partial data 9, 9 ′ extracted from a plurality of original data 7, 7 ′ to be encrypted are combined. A digital watermark process is performed on the combined data 10 so that a plurality of original data 7 and 7 'can be digitally processed collectively, thereby shortening the processing time in the digital watermark embedding process step S8. I have to.

  Next, the data encryption program 6 executes an embedded image file storing step S9 for storing the embedded image file 13 generated in the digital watermark embedding processing step S8 in a predetermined storage medium 14, and also the original data 7, Generate missing files 15 and 15 'by deleting some data 9 and 9' from the concealed data 8 and 8 'encrypted 7' and save the missing files 15 and 15 'in a predetermined storage medium 16. The missing file saving step S10 is executed.

  In the embedded image file saving step S9 and the missing file saving step S10, the embedded image file 13 and the missing files 15 and 15 ′ are saved in different storage media 14 and 16, respectively. For example, the embedded image file 13 is stored in an external storage device such as a USB memory connected to the computer, and the missing files 15 and 15 ′ are stored in an internal storage device such as a hard disk inside the computer.

  As described above, the data encryption program 6 stores the embedded image file 13 and the missing files 15 and 15 ′ in different storage media 14 and 16, respectively, so that even if one of the files is stolen, the original data is stored. It cannot be restored to 7,7 '.

  The path name and file name indicating the storage location of the key data used in the digital watermark embedding processing step S8 and the data to be encrypted stored in the encrypted data specifying step S2 are also stored in a predetermined storage medium. save.

  Finally, the data encryption program 6 executes an original data erasing step S11 for erasing the original data 7, 7 ′.

  In the original data erasing step S11, the concealment data 8, 8 ′, the partial data 9, 9 ′, the merged data 10 and the like generated during the processing together with the original data 7, 7 ′ are simultaneously erased.

  In the data transmission system, the missing files 15, 15 ′ generated in the missing file storage step S10 of the data encryption program 6 are transmitted as encrypted data from the sending client computer 2 to the receiving client computers 3 and 4, and the data The embedded image file 13 generated in the embedded image file storage step S9 of the encryption program 6 is transmitted from the transmission client computer 2 to the server computer 1 as key data.

  The data encryption program 6 is an embodiment of the present invention, and the embodiment of the present invention is not limited to the data encryption program 6.

  That is, in the data encryption program 6, the concealment processing step S4, the union processing step S6, and the image file selection step S7 are not essential processes, but are processes added as necessary. The embedded image file 13 and the missing files 15, 15 ′ may be stored in different storage media 14, 16, respectively, and the storage destination may be an internal storage device of the computer or an external storage device. Alternatively, it may be an internal / external storage device of another computer connected to the computer executing the data encryption program 6 by a communication line network.

  As described above, in the data encryption program 6, a part of the original data 7, 7 ′ is extracted, and the partial data 9, 9 ′ is converted into the image files 11, 11 ′ using digital watermark processing. , 11 ", the processing time for performing digital watermark processing can be shortened, and practical data encryption processing can be performed.

  Moreover, in the data encryption program 6, the embedded image file 13 in which the partial data 9, 9 ′ is embedded in the image file 11, 11 ′, 11 ″ and the partial data 9, 9 from the original data 7, 7 ′. Since the missing files 15 and 15 with 'deleted' are stored in different storage media 14 and 16, respectively, even if one of the files is stolen, it must be restored to the original data 7 and 7 '. And leakage of information included in the original data 7, 7 ′ can be prevented.

  In the data encryption program 6, since the original data 7, 7 ′ is encrypted before the partial data 9, 9 ′ is extracted from the original data 7, 7 ′, digital watermark processing is performed. Even if the partial data 9,9 ′ can be restored, the restored partial data 9,9 ′ and the missing file 15,15 ′ cannot be restored to the original data 7,7 ′. Data 7 and 7 'are protected twice, and leakage of information contained in the original data 7 and 7' can be prevented even better.

  In the data encryption program 6, partial data 9 and 9 ′ extracted from a plurality of original data 7 and 7 ′ are combined and then embedded in the image file 11, 11 ′ and 11 ″. The plurality of original data 7, 7 ′ can be encrypted in a lump, and the processing time for encrypting the plurality of original data 7, 7 ′ can be shortened.

  Further, in the data encryption program 6, the image files 11, 11 ′ used for the digital watermarking process according to the size of the partial data 9, 9 ′ from among the plural types of image files 11, 11 ′, 11 ″. , 11 "is selected, the processing time can be shortened when the size of the partial data 9,9 'is small, and the processing time corresponding to the size of the partial data 9,9' Can encrypt data.

  Note that the embedded image file 13 and the missing files 15 and 15 ′ encrypted by the data encryption program 6 are converted into the original data 7 and 15 using a restoration program that performs the reverse process of the data encryption program 6. Restored to 7 '.

The schematic diagram which shows the hardware constitutions of the data transmission system which concerns on this invention. Explanatory drawing which shows the flow of a process by the data transmission system which concerns on this invention. The schematic diagram which shows the process by the data transmission system which concerns on this invention. The schematic diagram which shows the process by the data transmission system which concerns on this invention. The schematic diagram which shows the process by the data transmission system which concerns on this invention. The schematic diagram which shows the process by the data transmission system which concerns on this invention. The flowchart of the data encryption program which concerns on this invention. The schematic diagram which shows the process by the data encryption program which concerns on this invention.

Explanation of symbols

1 server computer 2 sending client computer
3,4 Receiving client computer 4 Electronic communication network 6 Data encryption program
7,7 'original data
8,8 'encrypted data
9,9 'Partial data
10 Combined data
11,11 ', 11 "image file
12,14,16 Storage media
13 Embedded image files
15,15 'missing file

Claims (3)

A data transmission system for transmitting data between a transmission client computer and a reception client computer via a server computer,
The transmission client computer encrypts data to be transmitted, generates encrypted data and key data for restoring the encrypted data, transmits the encrypted data to the reception client computer, and sends the key data to the server computer. To
The server computer notifies the receiving client computer after receiving the key data from the sending client computer, sends the key data to the receiving client computer after receiving a request from the receiving client computer, and notifies the sending client computer,
The receiving client computer restores the encrypted data using the key data received from the server computer.
A data transmission system characterized by that.   When a plurality of receiving client computers are designated from the sending client computer, the server computer notifies each receiving client computer after receiving key data from the sending client computer, and after receiving a request from each receiving client computer 2. The data transmission system according to claim 1, wherein the key data is transmitted to the receiving client computer and notified to the transmitting client computer.   2. The transmission client computer extracts key data to be transmitted, and generates key data by embedding the extracted data in an image file using digital watermark processing. Item 3. The data transmission system according to Item 2.

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