JP4734069B2 - COMMUNICATION SYSTEM, TRANSMITTER DEVICE, RECEPTION DEVICE, AND PROGRAM - Google Patents

Description

  The present invention relates to a communication system or the like configured by communication-connecting a transmission-side device that encrypts and transmits character data and a reception-side device that decrypts character data from received encryption data.

Conventionally, in the fields of data management and data communication, encryption techniques using various methods have been used in order to prevent data leakage and improve security reliability.
For example, a technique for decrypting ciphertext by jointly using a plurality of secret keys to decrypt plaintext is known (see Patent Document 1).
On the other hand, an encryption technique called a one-time-pad using a key (random number sequence) having the same length as that of plain text is known.
JP 2002-359615 A

However, even when data is encrypted and exchanged between a plurality of devices, there is a risk that the key is overlooked and the data is decrypted as long as the key used for encryption is fixed.
On the other hand, in the encryption using the one-time pad method described above, since the key used for encryption is disposable, the risk of data decryption is low, but it is necessary to generate a highly messy key, which makes the processing complicated. There was a problem that there was.

  Therefore, an object of the present invention is to realize a new encryption mechanism with excellent secrecy.

The first invention for solving the above problems is:
A communication system comprising a transmission side device that encrypts and transmits character data and a reception side device that decrypts the character data from the received encryption data, and is connected to each other,
The transmitting device is:
Each character constituting the character data is displayed in the display position information indicating the display position when the document data is displayed on the Web browser of the same character in the predetermined document data that can be displayed on the Web browser. An encryption means (for example, the processing device 110 shown in FIG. 4) for encrypting the character data into encrypted data by conversion;
Transmission means for transmitting the encrypted encrypted data (for example, the communication device 130 shown in FIG. 4);
With
The receiving side device
Receiving means (for example, the communication device 530 shown in FIG. 4) for receiving the encrypted data transmitted from the transmission side device;
Each of the display position information constituting the received encrypted data is converted into characters displayed at the display position when the same document data as the predetermined document data is displayed on the Web browser, thereby the encrypted data. Decoding means for decoding (for example, the processing device 510 shown in FIG. 4);
It is a communication system provided with.

According to the first aspect, the transmission side device displays the document data on the Web browser for each character constituting the character data in the same character as the character in the document data that can be displayed on the Web browser. The character data can be encrypted by converting it into display position information indicating the display position at the time. On the other hand, the receiving device displays each display position information constituting the encrypted data received from the transmitting device when the same document data as the document data used for encryption in the transmitting device is displayed on the Web browser. The encrypted data can be decrypted by converting it into a character displayed at a position.
According to this, since the conversion result is different for the same character depending on whether each character constituting the character data is converted into display position information indicating which character display position in the document data, the confidentiality of the encrypted data Can be held. Therefore, an encryption mechanism with excellent secrecy can be realized by a simple process of converting character data into a list of display position information.

The second invention is the communication system of the first invention,
The transmitting device is:
Transmitting-side URL storage means for storing a plurality of URL information in a predetermined order (for example, URL list (A) 165 shown in FIG. 10);
Transmission-side document acquisition means for acquiring document data specified by the URL information stored in the transmission-side URL storage means according to the storage order of the transmission-side URL storage means as document data used for encryption of the encryption means (For example, the processing device 110 and the communication device 130 shown in FIG. 10);
Further comprising
The encryption unit changes the document data used for encryption to document data acquired by the transmission side document acquisition unit according to the storage order of the transmission side URL storage unit at a predetermined timing,
The receiving side device
Receiving URL storage means (for example, URL list (A) 5633 shown in FIG. 11) for storing the URL information stored by the transmitting URL storage means in the same order;
Receiving-side document acquisition means (for example, receiving document data specified by URL information stored in the receiving-side URL storage means as document data used for decoding by the decoding means in accordance with the storage order of the receiving-side URL storage means) , Processing device 510, communication device 530) shown in FIG.
Further comprising
The decryption means is a communication system that changes document data used for decryption to document data acquired by the reception-side document acquisition means in accordance with the storage order of the reception-side URL storage means at a predetermined timing.

  According to the second aspect of the invention, the transmission side device stores a plurality of URL information in which the order is defined. Then, according to the storage order of the URL information, the document data specified by the URL information is acquired as the document data used for encryption, and the document data used for encryption is acquired at a predetermined timing when encryption is performed. The document data can be changed. On the other hand, the receiving device stores the URL information in the same order as the transmitting device. Then, in accordance with the storage order of the URL information, the document data specified by the URL information is acquired as the document data used for the decryption, and the document data used for the decryption at a predetermined timing when decrypting is obtained. Can be changed. Therefore, since the converted display position information differs depending on the document data used for encryption, the confidentiality of the communication text can be improved.

The third invention is the communication system of the second invention,
The encryption unit sequentially converts each character constituting the character data into display position information, and encrypts when the converted display position information overlaps with the display position information converted so far. Change the document data to be used, and continue to encrypt the characters that make up the character data,
The decryption means sequentially converts each display position information constituting the received encrypted data into characters, and changes the document data used for decryption when the same display position information is converted again, In the communication system, display position information constituting the encrypted data is subsequently decrypted.

  According to the third aspect of the invention, when the transmitting side apparatus encrypts the character data, each character constituting the character data is sequentially converted into the display position information. Can overlap the display position information converted up to the previous time, the document data used for encryption can be changed. On the other hand, when decrypting the encrypted data, the receiving side device sequentially converts each display position information constituting the encrypted data into characters. However, when the same display position information is converted again, the receiving side device decrypts the encrypted data. The document data to be used can be changed.

The fourth invention is the communication system of the second invention,
The encryption means sequentially converts each character constituting the character data into display position information, and when the document data used for encryption is changed, a change notification code indicating that the character data has been changed, Set between the display position information converted before and after the change, create encrypted data,
Document used for decryption at the timing when the decryption means sequentially decrypts each display position information constituting the received encrypted data and detects that a change notification code is set in the encrypted data. This is a communication system in which data is changed and subsequently display position information constituting the encrypted data is decrypted.

  According to the fourth aspect of the invention, when the transmission side apparatus encrypts the character data, each of the characters constituting the character data is sequentially converted into the display position information, and the document used for the encryption. When the data is changed, the change notification code indicating the change can be set between the display position information converted before and after the change, and the encrypted data can be created. On the other hand, when the receiving side apparatus decrypts the encrypted data, the receiving side apparatus sequentially decrypts each display position information constituting the encrypted data and detects that the change notification code is set in the encrypted data. The document data used for decryption can be changed.

The fifth invention is the communication system of the second invention,
The encryption means changes document data used for encryption every time a predetermined number of character data is encrypted,
In the communication system, the decryption unit changes document data used for decryption each time decryption of the same number of encrypted data as the predetermined number is performed.

  According to the fifth aspect of the present invention, the transmission side apparatus can change the document data used for encryption every time a predetermined number of character data is encrypted when performing the encryption. On the other hand, when performing decryption, the receiving-side apparatus can change document data used for decryption each time decryption of the same number of encrypted data as the predetermined number is performed.

The sixth invention is the communication system of the first invention,
The encryption unit includes a transmission-side document change unit (for example, the processing device 110 shown in FIG. 4) that changes document data used for encryption.
The transmission side device is document specification information for specifying the document data, and is a document specification information transmission unit for transmitting the document specification information of the document data changed by the transmission side document change unit to the reception side device ( For example, the processing apparatus 110 and the communication apparatus 130) illustrated in FIG.
The receiving device further includes document specifying information receiving means (for example, the processing device 110 and the communication device 130 shown in FIG. 4) for receiving the document specifying information transmitted from the transmitting device,
The decrypting means is a communication system that decrypts the received encrypted data using document data specified in accordance with the received document specifying information.

  According to the sixth aspect, the transmission side apparatus can change the document data used for encryption. Then, the character specifying information for specifying the changed document data can be transmitted to the receiving device. On the other hand, the receiving side device can decrypt the encrypted data by using the document data specified according to the character specifying information received from the transmitting side device.

A seventh invention is a communication system according to any one of the first to sixth inventions,
The document data includes characters set with link information indicating a link with other document data,
The encryption means sequentially converts each character constituting the character data into display position information indicating the display position in the document data and encrypts it, and link information is set for the character at the display position. The document data used for encryption is changed to the document data of the link destination according to the link information, and subsequently the characters constituting the character data are encrypted,
The decrypting means sequentially converts each display position information constituting the received encrypted data into a character displayed at a display position indicated by the display position information in the document data, and decrypts the information. When link information is set for the character at the display position, the document data used for decryption is changed to the document data at the link destination according to the link information, and subsequently the display position information constituting the encrypted data is decrypted. It is a communication system.

  According to the seventh aspect, when the transmission side apparatus encrypts the character data, each of the characters constituting the character data is sequentially converted into display position information indicating the display position in the document data. If the link information indicating the link with other document data is set in the character at the display position, the document data used for encryption can be changed to the link destination document data. . On the other hand, when decrypting the encrypted data, the receiving device converts each display position information constituting the encrypted data into characters displayed at the display position indicated by the display position information in the document data in order. Decoding is performed, but when link information is set for the character at the display position, the document data used for decoding can be changed to the linked document data.

The eighth invention is the communication system of any one of the first to seventh inventions,
The document data is a communication system that is document data describing the contents of a Web page published on the Internet.

  According to the eighth aspect of the invention, it is possible to realize encryption and decryption of character data using document data describing the contents of a Web page published on the Internet.

The ninth invention
A transmitting device that encrypts character data and transmits the encrypted data to the receiving device;
Each character constituting the character data is displayed in the display position information indicating the display position when the document data is displayed on the Web browser of the same character in the predetermined document data that can be displayed on the Web browser. An encryption unit (for example, the processing device 110 shown in FIG. 4) that encrypts the character data into encrypted data by conversion;
Decryption for decrypting the encrypted data by converting each display position information constituting the encrypted data into characters displayed at the display position when the same document data as the predetermined document data is displayed on the Web browser A transmission-side apparatus communicably connected to a reception-side apparatus including means (for example, the processing apparatus 510 shown in FIG. 4).

The eleventh invention
Computer
Each character constituting the character data is converted into display position information indicating the display position when the document data is displayed with the Web browser, in the same character as the character in the predetermined document data that can be displayed with the Web browser. A program for causing the character data to function as encryption means (for example, the processing device 110 shown in FIG. 4) for encrypting the character data into encrypted data,
The encrypted data encrypted by the computer executing the program is
Decryption for decrypting the encrypted data by converting each display position information constituting the encrypted data into characters displayed at the display position when the same document data as the predetermined document data is displayed on the Web browser This is a program that is decoded by a receiving-side device that includes means (for example, the processing device 510 shown in FIG. 4).

  According to the ninth or eleventh invention, when each character constituting the character data is the same character as the character in the document data that can be displayed by the Web browser, the document data is displayed by the Web browser. The character data can be encrypted by converting it into display position information indicating the display position.

The tenth invention is
Each character constituting the character data is converted into display position information indicating the display position when the document data is displayed with the Web browser, in the same character as the character in the predetermined document data that can be displayed with the Web browser. In this way, the receiving side device decrypts the character data from the encrypted data transmitted from the transmitting side device provided with the encryption means (for example, the processing device 110 shown in FIG. 4) for encrypting the character data into the encrypted data. There,
Decryption for decrypting the encrypted data by converting each display position information constituting the encrypted data into characters displayed at the display position when the same document data as the predetermined document data is displayed on the Web browser It is a receiving side apparatus provided with a means (for example, the processing apparatus 510 shown in FIG. 4).

In addition, the twelfth invention
Each character constituting the character data is converted into display position information indicating the display position when the document data is displayed with the Web browser, in the same character as the character in the predetermined document data that can be displayed with the Web browser. A computer that is communicably connected to a transmission-side apparatus including an encryption unit (for example, the processing apparatus 110 shown in FIG. 4) that encrypts the character data into encrypted data.
Decryption for decrypting the encrypted data by converting each display position information constituting the encrypted data into characters displayed at the display position when the same document data as the predetermined document data is displayed on the Web browser It is a program for making it function as a means (for example, processing unit 510 shown in Drawing 4).

  According to the tenth or twelfth invention, each display position information constituting the encrypted data encrypted by the transmission side apparatus is stored in the same document data as the document data used for encryption in the transmission side apparatus. The encrypted data can be decrypted by converting the characters to be displayed at the display position when displayed on the browser.

According to the present invention, the transmitting-side device displays each character constituting the character data when the document data is displayed on the Web browser in the same character as the character in the document data that can be displayed on the Web browser. The character data can be encrypted by converting into display position information indicating the display position. On the other hand, the receiving device displays each display position information constituting the encrypted data received from the transmitting device when the same document data as the document data used for encryption in the transmitting device is displayed on the Web browser. The encrypted data can be decrypted by converting it into a character displayed at a position.
According to this, since the conversion result is different for the same character depending on whether each character constituting the character data is converted into display position information indicating which character display position in the document data, the confidentiality of the encrypted data Can be held. Therefore, an encryption mechanism with excellent secrecy can be realized by a simple process of converting character data into a list of display position information.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a communication system to which the present invention is applied will be described in detail with reference to the drawings.

[Overview]
The communication system according to the present embodiment includes, for example, a transmission-side device that encrypts plain text (character data) input by a user operation into communication text (encrypted data), and decrypts the communication text encrypted by the transmission-side apparatus. And a receiving side device for decoding plaintext.

  The sending side device encrypts each character constituting the plain text into a communication text by converting each character constituting the plain text into display position information indicating the same character display position when the predetermined HTML document is displayed on the Web browser. To do. On the other hand, the receiving device displays each display position information constituting the communication text as a character displayed at the display position when the same HTML document as the predetermined HTML document used for encryption is displayed on the Web browser. Decoding by converting to

  First, display position information indicating the display position of each character included in the HTML document when the HTML document is displayed on a Web browser will be described. FIG. 1A is a schematic diagram of a display, and shows a state in which a plurality of windows including a browser screen BW are activated. FIG. 1B is an enlarged view of the browser screen BW, and FIG. 1C is a diagram illustrating an example of a Web page displayed on the browser screen BW.

  In FIG. 1B, the browser screen BW includes an address bar AB, a page display area PW, and the like. The address bar AB includes a Web page (HTML document) displayed in the page display area PW. Information indicating the storage location is set. Specifically, for example, a URL or a path indicating a storage location in the apparatus is set. The Web browser reads the HTML document designated in the address bar AB, and displays it in the page display area PW as a Web page in which characters and images are arranged according to the HTML document.

  The arrangement position of each character included in the HTML document on the Web page is specified by the layout setting, format setting, etc. of the page defined in the HTML document. For example, according to the arrangement position P1 defined as the layout setting of the character string “abc” in the Web page shown in FIG. 1C, the characters “b”, “ The arrangement positions P2 and P3 of “c” are specified.

  The display position information indicating the display position of each character included in the HTML document may be an arrangement position on the Web page specified as described above, or may be as follows.

  That is, the coordinates of the specified arrangement position may be converted based on the display setting of the browser screen BW, and the display position of each character on the obtained page display area PW may be used as display position information. For example, if attention is paid to the arrangement position P1 of the character “a” on the Web page shown in FIG. 1C, the display position P11 on the page display area PW obtained as a result of the coordinate conversion is used as the display position information. .

  Alternatively, coordinate conversion of the display position of each character on the specified page display area PW is performed based on the arrangement position of the browser screen BW on the display, and the display position of each character on the obtained display is displayed. It may be position information. For example, when attention is focused on the display position P11 of the character “a” on the page display area PW shown in FIG. 1B, the display position P21 on the display obtained as a result of the coordinate conversion is used as the display position information.

  In the following description, it is assumed that the display position information is an arrangement position on the Web page, and each character constituting the plain text is converted into an arrangement position on the Web page and encrypted.

  2A and 2B are diagrams for explaining encryption when a character string “ggfh4cmkt” is input as plain text. FIG. 2A is a diagram illustrating an example of an HTML document, and FIG. 2B is an HTML diagram illustrated in FIG. FIG. 6 is a diagram showing an example of an HTML document of a linked page linked to a character string M in the document, and FIG. 5C is a diagram showing an example of an encrypted communication message.

  As shown in FIG. 2A, in the present embodiment, each character constituting the plain text is identified as described above, and the arrangement position on the Web page of the same character as the character in the HTML document is specified. A communication sentence is generated by converting to. That is, for example, the character “ggfh4c” in the plain text is converted into the arrangement positions of the characters g1, g2, f3, h4, 45, c6, respectively. In the present embodiment, when another HTML document is linked to the converted arrangement position, the HTML document used for encryption is changed to the HTML document of the link destination page. For example, if the character “m” in plain text is converted into the arrangement position of the character m7, the HTML document used for encryption is changed to the HTML document shown in FIG. Then, the character “kt” in the plain text is continuously converted into the arrangement position of, for example, the characters k8 and t9 on the Web page displaying the HTML document, and the communication text (FIG. 2C) is generated.

[First Embodiment]
First, the first embodiment will be described.

[overall structure]
FIG. 3 is a diagram illustrating an example of the overall configuration of the communication system 1a according to the first embodiment. In the first embodiment, a transmission-side device 10a and a reception-side device 50a that transmit and receive a communication text are connected via a communication line N to constitute a communication system 1a. Here, the communication line N means a communication path through which data can be exchanged. That is, the communication line N is meant to include a communication network such as a telephone communication network, a cable network, and the Internet in addition to a LAN using a dedicated line (dedicated cable) for direct connection or Ethernet (registered trademark). The communication method may be wired / wireless.

  In the communication system 1a of the first embodiment, the same HTML document group (for example, “HTML document group (A)”) is stored in advance in the storage devices of the transmission side device 10a and the reception side device 50a. This HTML document group (A) is used when performing encryption and decryption.

[Function configuration]
FIG. 4 is a diagram illustrating main functional blocks of the transmission side device 10a and the reception side device 50a according to the first embodiment.

(Sending device)
As shown in FIG. 4, the transmission side device 10a includes an input device 100, a processing device 110, a display device 120, a communication device 130, a storage device 140a, and the like.

  The input device 100 is realized by a keyboard provided with cursor keys, numeric keys, various function keys, etc., a pointing device such as a touch panel or a mouse, and when these are operated, an operation corresponding to the operation is performed. The signal is output to the processing device 110.

  The processing device 110 is constituted by a CPU or the like, and performs overall control of the transmission side device 10a by giving instructions to each functional unit constituting the transmission side device 10a, transferring data, and the like. Specifically, a processing program corresponding to an operation signal or the like input from the input device 100 is read from the storage device 140a and executed, and the processing result is stored in the storage device 140a.

  The display device 120 is a display device such as an LCD (Liquid Crystal Display) or an ELD (Electronic Luminescent Display), and displays various screens based on display signals input from the processing device 110.

  The communication device 130 is a device for exchanging information used inside the device with the outside via the communication line N, and controls communication with another device (for example, the receiving-side device 50a). The functions of the communication device 130 are realized by a wireless communication module, a modem, TA, a wired communication cable jack, a control circuit, and the like.

  The storage device 140a includes various IC memories such as ROM and RAM such as flash memory that can be updated and stored, a hard disk, and the like, and various processing programs related to the operation of the transmission side device 10a and data such as processing results by the processing programs are stored therein. Stored. The processing device 110 executes various processes based on the processing program and data read from the storage device 140a. In particular, in order to implement the first embodiment, a first encryption program 151, a conversion table creation program 153, an HTML document group (A) 155, and conversion table information 157 are stored.

  The first encryption program 151 is a program for encrypting plain text input by a user operation to generate a communication text and transmitting it to the reception side device 50a. The processing device 110 is configured to transmit the first encryption program 151 to the reception side device 50a. The first encryption process is executed according to

  Specifically, the processing apparatus 110 converts each character constituting the plain text on the Web page of the same character as the character in the HTML document to be converted (hereinafter referred to as “encryption target document”). A communication sentence is generated by sequentially converting to the arrangement position. As an encryption target document, an HTML document that is predetermined as a top page in the HTML document group (A) 155 is first selected. When another HTML document is linked to the converted arrangement position, the encryption target document is changed to a linked page.

  The conversion table creation program 153 is a program for creating the conversion table information 157, and the processing device 110 executes the conversion table creation processing according to the conversion table creation program 153 as a preparation stage before encrypting the plain text. . Specifically, the processing device 110 specifies the arrangement position on the Web page of the characters included in the encryption target document and the position (link position) in the encryption target document to which another HTML document is linked. The conversion table information 157 is stored in the storage device 140a.

  The HTML document group (A) 155 includes a plurality of descriptions in which layout information defining page layout settings, format information defining format settings such as font type and character size, link information defining link destination HTML documents, and the like are described. The HTML document is stored.

  The conversion table information 157 is generated as a result of the above-described conversion table creation process, and is stored for each HTML document. FIG. 5 is a data configuration example of the conversion table information 157. As shown in FIG. 5, the conversion table information 157 stores a character position table 1573 and link position data 1575 generated based on the HTML document, together with document specifying information 1571 for identifying the HTML document.

  For example, a path indicating the storage location of the HTML document, a file name, and the like are appropriately set in the document specifying information 1571.

  The character position table 1573 stores, for each character, an arrangement position on the Web page of characters included in the HTML document. FIG. 6 is a diagram showing a data configuration example of the character position table 1573. As shown in FIG. 6, in the character position table 1573, the correspondence between the characters in the HTML document and the arrangement positions on the Web page is set. The processing apparatus 110 specifies the arrangement positions on the Web page of all characters included in the HTML document by using layout information and format information, and generates a character position table 1573. Therefore, in the character position table 1573, when a plurality of the same characters are included in the HTML document, a plurality of arrangement positions corresponding to the characters are registered. For this reason, even if the same text is included in the plain text, it can be converted to a different location, so the confidentiality of the communication text is maintained and the plain text is estimated and decoded by frequency analysis. It becomes possible to prevent.

  The link position data 1575 stores the link position in the HTML document that is set to be linked with another HTML document. The processing device 110 specifies a link position in the HTML document by link information, and generates link position data 1575 in association with the document specifying information of the link destination page.

(Receiving device)
As shown in FIG. 4, the receiving-side device 50a includes an input device 500, a processing device 510, a display device 520, a communication device 530, a storage device 540a, and the like.

  The input device 500 is realized by a keyboard having cursor keys, numeric keys, various function keys, etc., a pointing device such as a touch panel or a mouse, and when these are operated, an operation corresponding to the operation is performed. The signal is output to the processing device 510.

  The processing device 510 is composed of a CPU or the like, and performs overall control of the receiving device 50a by giving instructions to each functional unit constituting the receiving device 50a, transferring data, and the like. Specifically, a processing program corresponding to an operation signal or the like input from the input device 500 is read from the storage device 540a and executed, and the processing result is stored in the storage device 540a.

  The display device 520 is a display device such as an LCD (Liquid Crystal Display) or ELD (Electronic Luminescent Display), and displays various screens based on display signals input from the processing device 510.

  The communication device 530 is a device for exchanging information used inside the device with the outside via the communication line N, and controls communication with another device (for example, the transmission-side device 10a). The function of the communication device 530 is realized by a wireless communication module, a modem, a TA, a wired communication cable jack, a control circuit, and the like.

  The storage device 540a is composed of various IC memories such as ROM and RAM such as flash memory that can be updated and stored, or a hard disk, and various processing programs related to the operation of the receiving-side device 50a and data such as processing results by the processing programs are stored therein. Stored. The processing device 510 executes various processes based on the processing program and data read from the storage device 540a. In particular, in order to realize the first embodiment, the first decryption program 551 and the same HTML document group (A) 553 as those stored in the transmission side apparatus 10a are stored, and the HTML document group (A) In 553, the same HTML document as the HTML document defined as the top page in the transmitting apparatus 10a is defined as the top page.

  The first decryption program 551 is a program for decrypting the communication text received from the transmission-side apparatus 10a and decrypting the plain text, and the processing device 510 executes the first decryption process according to the first decryption program 551.

  Specifically, the processing device 510 sets each arrangement position constituting the communication sentence on the Web page on which a conversion-target HTML document (hereinafter referred to as “decryption target document”) is displayed on the Web browser. The communication text is decoded by sequentially converting the characters at the position. As the decryption target document, the top page HTML document is first selected. When another HTML document is linked to the arrangement position, the encryption target document is changed to a linked HTML document.

[Process flow]
Next, the flow of processing of the communication system 1a in the first embodiment will be described.

(First encryption process)
First, the flow of the first encryption process executed in the transmission side apparatus 10a will be described with reference to FIG. Note that the processing described here is realized by the processing device 110 of the transmission side device 10a reading and executing the first encryption program 151 and the conversion table creation program 153.

  In the first encryption process, the processing device 110 first inputs a plain text according to a user operation (step s101). Subsequently, the processing apparatus 110 determines whether or not the top page conversion table information 157 has been created. If the processing device 110 has already been created (step s103: YES), the processing device 110 proceeds to step s107.

  On the other hand, if the top page conversion table information 157 has not been created (step s103: NO), the processing apparatus 110 executes the conversion table creation processing according to the conversion table creation program 153 and generates the conversion table information 157. (Step s105), the process proceeds to Step s107.

  In the conversion table creation process, the processing device 110 generates the character position table 1573 by specifying the position of each character included in the HTML document of the top page read from the HTML document group (A) 155 on the Web page. In addition, the link position data 1575 is generated by specifying the link position in the HTML document. Then, the processing device 110 stores the generated character position table 1573 and link position data 1575 in the storage device 140a as conversion table information 157 together with the document specifying information 1571 of the HTML document.

  In step s107, the processing apparatus 110 sets a top page in the encryption target document. Then, the processing device 110 executes the processing of loop A with the characters constituting the plaintext input in step s101 as the processing targets in order from the first character (steps s109 to s121). Hereinafter, the character to be processed in the loop A is referred to as “this character”.

  In the loop A, the processing apparatus 110 first selects an arrangement position registered in the character by referring to the character position table 1573 set in the conversion table information 157 of the encryption target document, and selects the character. Conversion to an arrangement position is performed (step s111). At this time, if a plurality of arrangement positions are registered for the character, the processing device 110 selects one arrangement position at random, for example.

  Next, the processing apparatus 110 refers to the link position data 1575 set in the conversion table information 157 of the encryption target document, and determines whether or not the converted arrangement position is a link position. And if it is not a link position (step s113: NO), the processing apparatus 110 will complete | finish the process in the loop A regarding this character.

  On the other hand, in the case of the link position (step s113: YES), the processing device 110 subsequently determines whether or not the conversion table information 157 of the link destination page has been created. If the processing device 110 has already been created (step s115: YES), the processing device 110 proceeds to step s119.

  On the other hand, if the conversion table information of the link destination page has not been generated (step s115: NO), the processing device 110 executes the conversion table generation processing according to the conversion table generation program 153 and generates the conversion table information 157. (Step s117), the process proceeds to Step s119. That is, the processing device 110 performs the same process as the conversion table creation process described in step s105 based on the HTML document of the link destination page read from the HTML document group (A) 155, and converts the conversion table information of the link destination page. 157 is created.

  In step s119, the processing apparatus 110 changes the encryption target document to a link destination page. If the processing of step s119 is executed, the processing device 110 ends the processing of the loop A related to the character.

  Then, when all the characters constituting the plaintext are converted into the arrangement positions, the processing device 110 ends the loop A, and then transmits the generated communication text to the reception-side device 50a (step s123). Exit.

(First decoding process)
Next, the flow of the first decoding process executed in the receiving apparatus 50a will be described with reference to FIG. Note that the processing described here is realized by the processing device 510 of the receiving-side device 50a reading out and executing the first decoding program 551.

  In this first decryption process, when the processing device 510 receives a communication message from the transmission side device 10a (step s201), first, the top page of the HTML document group (A) 553 is set as a decryption target document (step s201). s203). Then, the processing device 510 sets the arrangement positions constituting the communication text received in step s201 as processing targets in order from the beginning of the communication text, and executes the process of loop B (steps s205 to s213). Hereinafter, the arrangement position to be processed in the loop B is referred to as “this arrangement position”.

  In the loop B, first, the processing device 510 refers to the HTML document group (A) 553, and based on the layout information and format information defined in the decoding target document, the Web that displays the compound target document on the Web browser. A character at the current arrangement position on the page is specified, and converted to a character with the specified arrangement position (step s207).

  Next, the processing device 510 determines whether or not the arrangement position is a link position based on the link information defined in the decryption target document. If it is not the link position (step s209: NO), the processing device 510 ends the processing in the loop B related to the character.

  On the other hand, in the case of the link position (step s209: YES), the processing device 510 changes the decoding target document to the link destination page (step s211), and then ends the process of loop B relating to the character.

  Then, the processing device 510 ends the loop B when all the arrangement positions constituting the communication sentence are converted into characters, and ends the present processing. As a result of the first decryption process, the communication text is decrypted and the plain text is decrypted.

  As described above, according to the first embodiment, in the transmission-side apparatus 10a, each character constituting the plain text is placed at the position on the Web page of the same character as the character in the encryption target document. The plain text can be encrypted into the communication text by sequentially converting. On the other hand, the receiving device 50a can sequentially convert each arrangement position constituting the communication sentence into a character at the arrangement position in the document to be decoded, decode the communication sentence, and decode the plain text.

  According to this, when each character constituting the plain text is converted into an arrangement position on the Web page on which the HTML document is displayed, the conversion result is the same depending on which character arrangement position in the HTML document is selected. Therefore, the confidentiality of the encrypted data can be maintained.

  In addition, when encryption is performed, the encryption target document can be changed at the timing when the characters constituting the plain text are converted into the arrangement position that is the link position. On the other hand, when performing decoding, the decoding target document can be changed at the timing when the arrangement position constituting the communication sentence is converted into the character at the link position. Therefore, it is difficult to specify the HTML document as the encryption target document, and the confidentiality of the communication text can be improved.

[Second Embodiment]
Next, a second embodiment will be described. In addition, below, the same code | symbol is attached | subjected about the part similar to 1st Embodiment, and description is abbreviate | omitted.

[overall structure]
FIG. 9 is a diagram illustrating an example of the overall configuration of the communication system 1b according to the second embodiment. In the second embodiment, a plurality of transmission-side devices 10b (10b-1, 10b-2,...) That transmit a communication message are connected to the reception-side device 50b via a communication line N to establish the communication system 1b. It is composed.

  In the communication system 1b of the second embodiment, a URL list in which URL information of Web pages published on the Internet is stored in a specific order is stored in the storage device of each transmitting device 10b. On the other hand, the storage device of the receiving device 50b stores the same URL list as that stored in each transmitting device 10b connected for communication.

  For example, a URL list (A) is stored in the storage device of the sending apparatus 10b-1, and an HTML document describing the contents of a Web page according to the storage order of URL information set in the URL list (A). Is used to encrypt plaintext. On the other hand, in the receiving side device 50b, when a communication message is received from the transmitting side device 10b-1, the URL page (A) is referred to, and the Web page is stored according to the storage order of the URL information set in the URL list (A). An HTML document describing the contents of the message is acquired and used for decrypting the communication text.

[Function configuration]
FIG. 10 is a diagram illustrating main functional blocks of the transmission side device 10b and the reception side device 50b in the second embodiment.

(Sending device)
As shown in FIG. 10, the transmission-side device 10b includes an input device 100, a processing device 110, a display device 120, a communication device 130, a storage device 140b, and the like, as in the first embodiment.

  In order to realize the second embodiment, the storage device 140b of the transmission side apparatus 10b includes a second encryption program 161, a conversion table creation program 163, a URL list (for example, URL list (A)) 165, and a conversion The table information 167 and the transmission side device ID 169 that is ID information for identifying the transmission side device 10b are stored.

  The second encryption program 161 is a program for encrypting plain text input by a user operation and transmitting it to the receiving-side device 50b. The processing device 110 performs second encryption processing according to the second encryption program 161. Execute.

  Specifically, the processing device 110 sequentially converts each character constituting the plain text to the same character arrangement position as the character on the Web page displaying the HTML document to be converted (encryption target document). To generate a message. The encryption target document is acquired according to the storage order of the URL information set in the URL list (A) 165. Specifically, in the process of converting the characters constituting the plain text into the arrangement position, there is an overlap in the arrangement position where the converted arrangement position is the same as the previous arrangement position converted for the same encryption target document. If it occurs, a new HTML document is acquired according to the URL information in the next order, and the encryption target document is changed. Further, when another HTML document is linked to the converted arrangement position, the encryption target document is changed to a linked page as in the first embodiment.

  The conversion table creation program 163 is a program for creating the conversion table information 167, and the processing apparatus 110, as in the first embodiment, prepares the conversion table creation program 163 as a preparatory step before encrypting plain text. The conversion table creation process is executed according to the above. Specifically, the processing device 110 specifies the arrangement position on the Web page of the characters included in the encryption target document and the position (link position) in the encryption target document to which another HTML document is linked. The conversion table information 167 is stored in the storage device 140b.

  As described above, the URL list (A) 165 stores URL information of Web pages published on the Internet in an order specific to the transmitting apparatus 10b. Note that the URL information is deleted from the URL list (A) 165 when it is used to acquire the encryption target document, and the URL information once used is not used again. ing.

  The conversion table information 167 is generated as a result of the conversion table creation process, and includes a character position table 167a and link position data 167b generated based on the current document to be encrypted.

The character position table 167a stores, for each character, an arrangement position on the Web page of characters included in the document to be encrypted. The character position table 167a is shown in FIG. 6 in the first embodiment. Similar to the character position table 1573 described, the correspondence between the characters in the document to be encrypted and the arrangement positions on the Web page is set.
The link position data 167b stores the link position in the encryption target document set to be linked with another HTML document, and the link position data 167b includes the link position described in the first embodiment. Similar to the data 1575, the correspondence between the link position in the document to be encrypted and the linked page is set.

(Receiving device)
As shown in FIG. 10, the receiving-side device 50b includes an input device 500, a processing device 510, a display device 520, a communication device 530, a storage device 540b, and the like, as in the first embodiment.

  The storage device 540b of the receiving device 50b stores a second decryption program 561 and URL list information 563 in order to implement the second embodiment.

  The second decryption program 561 is a program for decrypting the communication text received from the transmission-side apparatus 10b and decrypting the plain text, and the processing device 510 executes the second decryption process according to the second decryption program 561.

  Specifically, the processing device 510 sequentially converts each arrangement position constituting the communication sentence into characters at the arrangement position in the HTML document (decoding target document) to be converted, and decodes the communication sentence. The decryption target document is acquired according to the storage order of the URL information set in the URL list 5633 (see FIG. 11) associated with the same transmission-side apparatus ID 5631 as the transmission-side apparatus ID 169 of the transmission-side apparatus 10b that transmitted the communication message. Is done. Specifically, when the same arrangement position is converted again for the same decryption target document in the process of converting the arrangement position constituting the communication sentence into characters, a new HTML document is created according to the URL information in the next order. Is acquired and the decryption target document is changed. Further, when another HTML document is linked to the arrangement position constituting the communication text, the decryption target document is changed to the link destination page as in the first embodiment.

  The URL list information 563 stores a URL list stored in each transmission-side device 10b that is connected for communication for each transmission-side device 10b. FIG. 11 is a diagram illustrating a data configuration example of the URL list information 563. As shown in FIG. 11, the URL list information 563 includes a transmission side device ID 5631 for identifying the transmission side device 10b, and a URL list (URL list (A) in FIG. 11) 5633. The same URL information is stored in the same order as the URL list stored in the corresponding transmitting apparatus 10b. Note that the URL information is deleted from the URL list 5633 when it is used to acquire the decryption target document, and the URL information once used is not used again.

[Process flow]
Next, the flow of processing of the communication system 1b in the second embodiment will be described.

(Second encryption process)
First, the flow of the second encryption process executed in the transmission side apparatus 10b will be described with reference to FIG. Note that the processing described here is realized by the processing device 110 of the transmission side device 10b reading and executing the second encryption program 161 and the conversion table creation program 163.

  In the second encryption process, the processing device 110 first inputs a plain text according to a user operation (step s301). Subsequently, the processing device 110 acquires an HTML document according to the top URL information set in the URL list (A) 165 and sets an encryption target document (step s303), and sets the top URL information as a URL. Delete from the list (A) 165 (step s305).

Subsequently, the processing apparatus 110 executes conversion table creation processing according to the conversion table creation program 163 to create conversion table information 167 (step s307).
In this conversion table creation process, the processing device 110 generates the character position table 167a by specifying the arrangement position of each character included in the encryption target document on the Web page, and at the same time, in the encryption target document. The link position data 167b is generated by specifying the link position. Then, the processing device 110 stores the generated character position table 167a and link position data 167b in the storage device 140b as conversion table information 167.

  Then, the processing device 110 executes the processing of loop C with the characters constituting the plaintext input in step s301 as processing targets in order from the first character (steps s309 to s329). Hereinafter, the character to be processed in the loop C is referred to as “this character”.

  In the loop C, the processing apparatus 110 first selects an arrangement position registered in the character with reference to the character position table 167a set in the conversion table information 167, and converts the character to the selected arrangement position. (Step s311). At this time, if a plurality of arrangement positions are registered for the character, the processing device 110 selects one arrangement position at random, for example.

  Next, the processing apparatus 110 determines whether or not the arrangement position converted in step s311 overlaps with the arrangement position converted so far for the same encryption target document. If there is no overlap (step s313: NO), the processing apparatus 110 proceeds to step s323 described later.

  On the other hand, if they are duplicated (step s313: YES), the processing device 110 acquires the HTML document according to the top URL information set in the URL list (A) 165 and changes the encryption target document. At the same time (step s317), the head URL information is deleted from the URL list (A) 165 (step s319).

  Then, the processing device 110 executes conversion table creation processing according to the conversion table creation program 163, and updates the conversion table information 167 (step s321). That is, the processing apparatus 110 performs the same process as the conversion table creation process described in step s307 based on the changed encryption target document, and creates the conversion table information 167 of the encryption target document. Then, the process returns to step s311, and the above-described processing is executed again for the character.

  In step s323, the processing apparatus 110 refers to the link position data 167b set in the conversion table information 167, and determines whether or not the converted arrangement position is a link position. If it is not the link position (step s323: NO), the processing device 110 ends the processing in the loop C related to the character.

  On the other hand, in the case of the link position (step s323: YES), the processing apparatus 110 subsequently acquires the HTML document of the link destination page and changes the encryption target document (step s325).

  Then, the processing device 110 executes conversion table creation processing according to the conversion table creation program 163, and updates the conversion table information 167 (step s327). That is, the processing apparatus 110 performs the same process as the conversion table creation process described in step s307 based on the changed encryption target document, and creates the conversion table information 167 of the encryption target document. When the process of step s327 is finished, the process in the loop C relating to the character is finished.

  Then, when all the characters constituting the plain text are converted into the arrangement positions, the processing device 110 ends the loop C, and then transmits the generated communication text together with the transmission side device ID 169 to the reception side device 50b ( Step s331), the process is terminated.

(Second decoding process)
Next, the flow of the second decoding process executed in the receiving device 50b will be described with reference to FIG. Note that the processing described here is realized by the processing device 510 of the receiving-side device 50b reading out and executing the second decoding program 561.

  In this second decryption process, when the processing device 510 receives a communication message from the transmitting device 10b (step s401), first, based on the transmitting device ID received together with the communication message, the processing device 510 obtains the URL list information 563. Select (step s403).

  Subsequently, the processing device 510 acquires an HTML document according to the top URL information set in the URL list (URL list (A)) 5633 of the URL list information 563 selected in step s401, and sets it as a decryption target document. (Step s405), the head URL information is deleted from the URL list (A) 5633 (step s407).

  Then, the processing device 510 executes the processing of the loop D with the arrangement positions constituting the communication text received in step s401 as processing targets in order from the head of the communication text (steps s409 to s423). Hereinafter, the arrangement position to be processed in the loop D is referred to as “this arrangement position”.

  In the loop D, the processing device 510 first determines whether or not the arrangement position overlaps with the arrangement position converted into characters for the same decoding target document up to the previous time. If there is no duplication (step s411: NO), the processing device 510 identifies the character at the current arrangement position based on the layout information and format information defined in the document to be decoded, and determines the current arrangement position. Is converted into the specified character (step s413).

  Subsequently, the processing device 510 determines whether or not the placement position is a link position based on the link information defined in the decryption target document. If it is not the link position (step s415: NO), the processing device 510 ends the processing of the loop D related to the character. On the other hand, in the case of the link position (step s415: YES), the processing device 510 acquires the HTML document of the link destination page and changes the decoding target document (step s417), and ends the processing of the loop D related to the character. .

  On the other hand, if it is determined in step s411 that they are duplicated, the processing device 510 newly acquires an HTML document according to the top URL information set in the URL list (A) 5633 and changes the decryption target document. (Step s419). Then, the processing device 510 deletes the head URL information from the URL list (A) 5633 (step s421), and ends the processing in the loop D related to the current position coordinates.

  Then, the processing device 510 ends the loop D when all the arrangement positions constituting the communication sentence are converted into characters, and ends the present processing. As a result of the second decryption process, the communication text is decrypted and the plain text is decrypted.

  As described above, according to the second embodiment, the transmission-side apparatus 10b acquires an HTML document describing the contents of a Web page according to the storage order of URL information set in the URL list (A) 165, It can be used for plaintext encryption. On the other hand, in the receiving side device 50b, when a communication message is received from the transmitting side device 10b, the URL list (A) 5633 storing the URL information in the same order as the transmitting side device 10b is referred to, and the URL list (A) An HTML document describing the contents of a Web page can be acquired in accordance with the storage order of the URL information set in, and used for decrypting the communication text.

  Further, when the arrangement position converted in the process of converting the characters constituting the plaintext into the arrangement position overlaps with the arrangement position converted up to the previous time for the same encryption target document, An HTML document can be newly acquired according to the URL information in the next order, and the encryption target document can be changed. On the other hand, when the same arrangement position is converted again in the process of converting the arrangement position constituting the communication sentence into characters, the receiving side device 50b newly acquires an HTML document according to the URL information in the next order, and is decrypted. You can change the document.

  That is, when performing encryption, the case where the document is converted to the same arrangement position is detected, the encryption target document is changed, and the character is converted into the arrangement position on the Web page displaying the changed encryption target document. Therefore, even if the same character is included in the plain text, the character is not converted to the same arrangement position. Furthermore, the URL information set in the URL list (A) common to the transmission side device 10b and the reception side device 50b is deleted when it is used to acquire an HTML document and is not used again. Yes. Therefore, encryption similar to the one-time pad method can be easily realized, and the confidentiality of the encrypted data can be improved.

  Note that the URL information set in the URL list (A) common to the transmission side apparatus 10b and the reception side apparatus 50b is used for encryption in the transmission side apparatus 10b and decryption in the reception side apparatus 50b as described above. Since it is deleted when it is used to acquire an HTML document, URL information may be added to the URL list (A) as follows.

  In other words, when the arrangement position converted in the process of converting the characters constituting the plain text into the arrangement position overlaps with the arrangement position converted up to the previous time, for example, the Web published on the Internet The URL information of the page is acquired at random. Alternatively, the URL information is acquired by receiving an input by a user operation. Then, the URL information (A) 165 is updated by adding the acquired URL information to the tail, and each character constituting the URL information is encrypted using, for example, the document to be encrypted at the time, and communication is performed. Insert in the sentence.

  On the other hand, in the receiving side device 50b, when the same arrangement position is converted again in the process of converting the arrangement position constituting the communication sentence into the character, the URL information inserted immediately after is extracted and at that time. The URL information is decrypted using the decryption target document. Then, the URL list information 563 is updated by adding to the tail of the corresponding URL list (A) 5633.

  Further, as described above, when URL information is inserted into a communication sentence and transmitted to the receiving-side apparatus 50b, for example, a character string such as “http”, “www”, “com”, “ne”, or “jp” is used. Corresponding code information may be set in advance, and these character strings included in the URL information may be converted into corresponding code information, encrypted, and inserted into the communication text.

[Modification]
The preferred embodiments of the present invention have been described above, but the present invention is not limited to those described above, and can be changed as appropriate without departing from the spirit of the invention.

  For example, in the first embodiment, the top page of the HTML document group (A) is used first in the encryption at the transmission side device 10a and the decryption at the reception side device 50a. .

  That is, the transmission side apparatus 10a may select an HTML document to be used first at the time of encryption at random. In this case, the transmitting apparatus 10a transmits document specifying information such as a file name for specifying the randomly selected HTML document to the receiving apparatus 50a together with a communication text. At this time, each character constituting the document specifying information is encrypted using, for example, an HTML document on the top page of the HTML document group (A) 155. On the other hand, the receiving-side device 50a decrypts the document specifying information received together with the communication text by using the HTML document on the top page of the HTML document group (A) 553, and specifies the HTML document to be used first at the time of decoding.

  Alternatively, the transmitting device 10a calculates the appearance tendency of characters included in each HTML document, and selects an HTML document having a high appearance tendency of characters included in plain text as the first HTML document used for encryption. It is good. According to this, illegal decryption by frequency analysis or the like can be prevented, and the confidentiality of the communication text can be further enhanced.

  In the second embodiment, in the process of converting the characters constituting the plain text into the arrangement position in the transmission side device 10b, the encrypted document is changed when the converted arrangement position overlaps. The change timing of the encryption target document is not limited to this.

  For example, in the transmission side apparatus 10b, when a predetermined number of characters set in advance are converted into arrangement positions, a new HTML document may be acquired according to the URL information in the next order, and the encryption target document may be changed. In this case, the receiving device 50b newly acquires an HTML document according to the URL information in the next order when the predetermined number of arrangement positions are converted into characters, and changes the decoding target document.

  Alternatively, the transmission side device 10b may insert a predetermined change notification code in the communication text at random timing. Then, when the change notification code is inserted into the communication text, an HTML document may be newly acquired according to the URL information in the next order, and the encryption target document may be changed. That is, in the communication text, the change notification code is set between the arrangement positions converted before and after the encryption target document is changed. In this case, the receiving side device 50b acquires the HTML document according to the URL information in the next order at the timing when the change notification code in the communication text is detected, and changes the decryption target document.

  In this way, when encrypting a message, the document to be encrypted can be changed at a predetermined timing. Therefore, it is difficult to specify an HTML document to be encrypted, and the message is concealed. The sex can be further enhanced.

  In the first embodiment and the second embodiment, when the transmission side device converts the characters constituting the plain text into the arrangement position which is the link position, the encryption target document is changed to the HTML document of the link destination page. However, it may be as follows. That is, when the arrangement position is the link position, the encryption target document may be changed by selecting or acquiring one HTML document at random, for example. According to this, since it is possible to make it more difficult to specify the HTML document to be encrypted, the confidentiality of the communication text can be improved. In this case, the transmission side apparatus encrypts the document specifying information such as the file name or URL information of the selected HTML document using the encryption target document before the change, and inserts it in the communication text.

  On the other hand, when the arrangement position in the communication text is the link position, the receiving side apparatus extracts the document specifying information inserted immediately after, and decodes it using the decoding target document at that time. Then, the decoding target document is changed to an HTML document specified by the extracted character specifying information.

  In addition, as described above, the transmission side device may generate a communication sentence using the display position on the display as the display position information. In this case, for example, a plain text input may be received by a selection operation on the display. The user selects (clicks) a character in the Web page displayed on the browser screen with an input device such as a mouse, thereby inputting position information corresponding to each plaintext character. The transmission side device enumerates the input coordinate values of the selection operation position on the display to generate a communication sentence, and transmits it to the reception side device. On the other hand, the receiving side device converts the coordinate value of the selection operation position into a display position on the page display area of the browser screen, and converts the display position on the page display area to the arrangement position on the Web page. . Then, the communication text is decrypted by identifying the character at the arrangement position on the Web page displaying the decryption target document, and the plain text is decrypted.

In the first embodiment and the second embodiment has been described as using an HTML document as document data to be used for encryption and decryption, SGML (Standard Generalized Markup Language) , described in a markup language such as T E _X Of course, it is also possible to use the document data.

The figure for demonstrating display position information. The figure for demonstrating encryption of a plaintext. The figure which shows an example of the whole structure of the communication system in 1st Embodiment. The figure which shows the main functional blocks of the transmission side apparatus in 1st Embodiment, and a reception side apparatus. The figure which shows the data structural example of conversion table information. The figure which shows the data structural example of a character position table. The flowchart for demonstrating the flow of a 1st encryption process. The flowchart for demonstrating the flow of a 1st decoding process. The figure which shows an example of the whole structure of the communication system in 2nd Embodiment. The figure which shows the main functional blocks of the transmission side apparatus in 2nd Embodiment, and a reception side apparatus. The figure which shows the data structural example of URL list information. The flowchart for demonstrating the flow of a 2nd encryption process. The flowchart for demonstrating the flow of a 2nd decoding process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Communication system 10a Transmission side apparatus 100 Input apparatus 110 Processing apparatus 120 Display apparatus 130 Communication apparatus 140 Storage apparatus 151 1st encryption program 153 Conversion table creation program 155 HTML document group (A)
157 Conversion table information 50a Reception side device 500 Input device 510 Processing device 520 Display device 530 Communication device 540 Storage device 551 First decryption program 553 HTML document group (A)
N communication line

Claims (10)

A communication system comprising a transmission side device having an encryption means for encrypting character data and a reception side device having a decryption means for decrypting character data from the encryption data,
The encryption unit of the transmission side device includes:
First conversion processing for converting, in order, predetermined character data that can be displayed by a Web browser into display position information representing a display position of the same character in the target document, with each character constituting the character data as the target document. And when there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is used as a new target document. By continuing the first conversion process, the character data is encrypted into the encrypted data,
The decoding means of the receiving device is
Second conversion for sequentially converting each display position information constituting the encrypted data into characters at a display position corresponding to the display position information when the target document is displayed, using the predetermined document data as a target document. When processing is performed and there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is set as a new target document. The communication system is characterized in that the encrypted data is decrypted into the character data by continuously performing the second conversion process. Using predetermined document data that can be displayed by a Web browser as a target document, each display position information constituting the encrypted data is sequentially converted into characters at a display position corresponding to the display position information when the target document is displayed. When the second conversion process is performed and there is link information representing a link with other document data in the character at the display position of the target document, the document data at the link destination according to the link information is updated. A transmission-side device that transmits encrypted data that can be decrypted by a reception-side device that includes decryption means for decrypting the encrypted data by continuing the second conversion process as a target document,
Character data have a encryption means for encrypting to the encrypted data,
The encryption means includes
With the predetermined document data as a target document, a first conversion process for sequentially converting each character constituting the character data into display position information representing the display position of the same character in the target document, When there is link information representing a link with other document data in the character at the display position of the target document, the first conversion process is performed using the linked document data according to the link information as a new target document. A transmitting-side apparatus, wherein the character data is encrypted into the encrypted data by continuing. A first conversion process is performed in which predetermined document data that can be displayed by a Web browser is used as a target document, and each character constituting the character data is sequentially converted into display position information representing the display position of the same character in the target document. When there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is used as a new target document. A receiving-side apparatus that receives encrypted data encrypted by a transmitting-side apparatus that includes an encryption unit that encrypts the character data by continuously performing one conversion process;
A decoding means for decoding the character data from the encrypted data,
The decoding means includes
As target document the predetermined document data, said each of said display position information which constitute the encrypted data, the second conversion for converting the order to letters display position corresponding to the display position information at the time of displaying the target document When processing is performed and there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is set as a new target document. The reception-side apparatus, wherein the encrypted data is decrypted into the character data by continuing the second conversion process. Using predetermined document data that can be displayed by a Web browser as a target document, each display position information constituting the encrypted data is sequentially converted into characters at a display position corresponding to the display position information when the target document is displayed. When the second conversion process is performed and there is link information representing a link with other document data in the character at the display position of the target document, the document data at the link destination according to the link information is updated. As a target document, by continuing the second conversion process, a computer connected to be able to communicate with a receiving-side apparatus including a decrypting unit that decrypts the encrypted data ,
With the predetermined document data as a target document, a first conversion process for sequentially converting each character constituting character data into display position information representing the display position of the same character in the target document is performed. When there is link information representing a link with other document data in the character at the display position of the target document, the first conversion process is continued using the linked document data according to the link information as a new target document. A program for causing the character data to function as encryption means for encrypting the character data into the encrypted data . A first conversion process is performed in which predetermined document data that can be displayed by a Web browser is used as a target document, and each character constituting character data is sequentially converted into display position information representing the display position of the same character in the target document. When there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is used as a new target document. (1) A computer capable of receiving encrypted data encrypted by a transmission-side apparatus having an encryption means for encrypting the character data by continuing the conversion process ,
As target document the predetermined document data, said each of said display position information which constitute the encrypted data, the second conversion for converting the order to letters display position corresponding to the display position information at the time of displaying the target document When processing is performed and there is link information representing a link with other document data in the character at the display position of the target document, the link destination document data according to the link information is set as a new target document. A program for causing the encrypted data to function as a decrypting means for decrypting the encrypted data by continuing the second conversion process. A communication system comprising a transmission side device having encryption means for encrypting character data, and a reception side device having decryption means for decrypting character data from received encryption data,
The transmitting device is:
Transmitting-side URL storage means for storing a plurality of URL information in a predetermined order;
Acquires document data that can be displayed by a Web browser specified by the URL information stored in the transmission-side URL storage unit as document data used for encryption by the encryption unit in accordance with the storage order of the transmission-side URL storage unit Sending document acquisition means for
With
The encryption means of the transmission side device is:
First conversion for sequentially converting each character constituting the character data into display position information representing the display position of the same character in the target document, using the document data acquired by the transmission side document acquisition means as a target document While performing the process, at a predetermined timing, the target document is changed to the document data acquired by the transmission side document acquisition unit according to the storage order of the transmission side ERL storage unit, and the first conversion process is continued. By going, the character data is encrypted into the encrypted data,
The receiving side device
Receiving URL storage means for storing the URL information stored in the transmitting URL storage means in the same order;
Receiving-side document acquisition means for acquiring document data specified by the URL information stored in the receiving-side URL storage means according to the storage order of the receiving-side URL storage means, as document data used for decoding by the decoding means;
With
The decoding means of the receiving side device
Using the document data acquired by the receiving-side document acquisition means as a target document, the display position information constituting the encrypted data is changed to a character at a display position corresponding to the display position information when the target document is displayed. While performing the second conversion processing to convert in order, at a predetermined timing, the target document is changed to the document data acquired by the transmission side document acquisition means according to the storage order of the transmission side URL storage means, A communication system, wherein the encrypted data is decrypted into the character data by continuing the second conversion process. The encryption unit sequentially converts each character constituting the character data into display position information, and encrypts when the converted display position information overlaps with the display position information converted so far. Change the document data to be used, and continue to encrypt the characters that make up the character data,
The decryption means sequentially converts each display position information constituting the received encrypted data into characters, and changes the document data used for decryption when the same display position information is converted again, Subsequently, the display position information constituting the encrypted data is decrypted.
The communication system according to claim 6. The encryption means sequentially converts each character constituting the character data into display position information, and when the document data used for encryption is changed, a change notification code indicating that the character data has been changed, Set between the display position information converted before and after the change, create encrypted data,
Document used for decryption at the timing when the decryption means sequentially decrypts each display position information constituting the received encrypted data and detects that a change notification code is set in the encrypted data. Changing the data and subsequently decrypting the display position information constituting the encrypted data,
The communication system according to claim 6. The encryption means changes document data used for encryption every time a predetermined number of character data is encrypted,
The decryption means changes document data used for decryption every time decryption of the same number of encrypted data as the predetermined number is performed.
The communication system according to claim 6.   The communication system according to any one of claims 1 and 6 to 9, wherein the document data is document data describing contents of a Web page published on the Internet.

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