WO2010106669A1 - Dispositif de codage de document électronique, procédé de codage de document électronique, programme de codage de document électronique et dispositif de décodage de document électronique - Google Patents

Dispositif de codage de document électronique, procédé de codage de document électronique, programme de codage de document électronique et dispositif de décodage de document électronique Download PDF

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Publication number
WO2010106669A1
WO2010106669A1 PCT/JP2009/055483 JP2009055483W WO2010106669A1 WO 2010106669 A1 WO2010106669 A1 WO 2010106669A1 JP 2009055483 W JP2009055483 W JP 2009055483W WO 2010106669 A1 WO2010106669 A1 WO 2010106669A1
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WO
WIPO (PCT)
Prior art keywords
electronic document
area
character string
concealment
unit
Prior art date
Application number
PCT/JP2009/055483
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English (en)
Japanese (ja)
Inventor
阿南　泰三
Original Assignee
富士通株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to PCT/JP2009/055483 priority Critical patent/WO2010106669A1/fr
Publication of WO2010106669A1 publication Critical patent/WO2010106669A1/fr

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/60—Protecting data
    • G06F21/62—Protecting access to data via a platform, e.g. using keys or access control rules
    • G06F21/6209—Protecting access to data via a platform, e.g. using keys or access control rules to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F40/00—Handling natural language data
    • G06F40/10—Text processing
    • G06F40/166—Editing, e.g. inserting or deleting

Definitions

  • Embodiments disclosed herein include an electronic document encryption device, an electronic document encryption method, an electronic document encryption program, and an electronic document encryption program that conceal part or all of an electronic document, and decrypting an electronic document that is partially or entirely concealed
  • the present invention relates to an electronic document decryption apparatus.
  • a concealment processing apparatus using one of such techniques sets a concealment area in a part of the original electronic document.
  • the hidden area is stored in the storage unit as mask data.
  • the concealment processing device develops a bit map of the character code in the original electronic document and creates intermediate data by covering a part thereof with mask data.
  • the concealment processing device creates an electronic document in which a part of the area is concealed by converting the intermediate data into an electronic document of a predetermined format.
  • a user who wants to edit an electronic document may edit the electronic document after setting a concealment area in a part of the electronic document. For example, the user may delete a part of a sentence or a figure located before the hidden area, or add a new sentence or figure before the hidden area.
  • the position of the set concealment area is shifted from the position of the part that is originally desired to be concealed.
  • the position of the set concealment area deviates from the position of the part originally intended to be concealed, the user has to reset the concealment area. Therefore, a technique for reducing such user workload is desired.
  • the present specification provides an electronic document encryption apparatus that does not require resetting of the hidden area even if the user edits the electronic document after the hidden area is set in part or all of the electronic document.
  • the purpose is to do.
  • an electronic document encryption device includes an operation unit that edits an electronic document represented as electronic data, and a processing unit that sets a concealment area that conceals a character string or an object included in at least a part of the electronic document.
  • the processing unit sets a region on the electronic document input via the operation unit as a concealment region, and stores a table recording the position and size of the concealment region on the electronic document in a predetermined region of the electronic document.
  • the position of the character string or object to be hidden by the hidden area varies depending on the function and the position of the hidden area or the position of the inserted or deleted character string or object, the movement of the character string or object to be hidden
  • a function of correcting the position of the hidden area according to the amount and recording the corrected position of the hidden area in the table is realized.
  • an electronic document decryption apparatus is an electronic document represented as electronic data, and a character string included in at least a part of the electronic document or a concealment area for concealing an object is set, and a character string included in the concealment area
  • an object is encrypted
  • an input unit that obtains an electronic document having a table that records the position and size of the hidden area on the electronic document and a processing unit that decrypts the electronic document are included.
  • the processing unit realizes a function of decrypting the encrypted character string or object and a function of relocating the decrypted character string or object at the current position of the hidden area with reference to the table.
  • an electronic document encryption method for encrypting a character string or an object included in at least a part of an electronic document represented as electronic data.
  • an area on the electronic document input via the operation unit is set as a hidden area, and a table recording the position and size of the hidden area on the electronic document is stored in a predetermined area of the electronic document.
  • the position of the character string or object to be concealed by the concealment area changes from the position of the concealment area and the position of the deleted character string or object, depending on the movement amount of the character string or object to be concealed
  • the position of the concealment area is corrected, and the position of the concealment area after correction is recorded on the table.
  • an electronic document encryption program having instructions for causing a computer to execute encryption of a character string or an object included in at least a part of an electronic document represented as electronic data.
  • This electronic document encryption program sets a region on an electronic document input via the operation unit as a concealment region, and stores a table recording the position and size of the concealment region on the electronic document in a predetermined region of the electronic document.
  • the concealment area changes from the position of the concealment area and the position of the deleted character string or object, depending on the movement amount of the character string or object to be concealed To correct the position of the concealment area and record the position of the concealment area after correction on the computer. To row.
  • the electronic document encryption apparatus disclosed herein, after a hidden area is set in part or all of an electronic document, the user does not need to edit the electronic document or reset the hidden area. There is an effect.
  • FIG. 1 is a schematic configuration diagram of an electronic document encryption apparatus according to an embodiment.
  • FIG. 2 is a functional block diagram of the processing unit of the electronic document encryption apparatus showing functions realized for executing processing for concealing part or all of the electronic document.
  • FIG. 3A is a diagram illustrating an example of an original document in which a hidden area is not set.
  • FIG. 3B is a diagram illustrating an example of an encrypted document in which a concealment area on an original document is filled with black.
  • FIG. 3C is a diagram illustrating an example of an encrypted document in which an encryption process as an image is performed on a hidden area on an original document.
  • FIG. 4A is a diagram illustrating an example of a hidden area set in an electronic document.
  • FIG. 4A is a diagram illustrating an example of a hidden area set in an electronic document.
  • FIG. 4B is a diagram illustrating an example of the divided concealment area when the electronic document is edited after the concealment area is set.
  • FIG. 5 is a diagram illustrating an example of a hidden area management table.
  • FIG. 6 is a diagram showing an operation flowchart of encryption processing when a concealment area is set, which is controlled by a computer program executed on the processing unit of the electronic document encryption apparatus.
  • FIG. 7 is a diagram showing an operational flowchart of a hidden area correction process when an electronic document in which a hidden area is set, which is controlled by a computer program executed on the processing unit of the electronic document encryption apparatus, is edited. .
  • FIG. 8 is a schematic configuration diagram of an electronic document decryption apparatus according to one embodiment.
  • FIG. 8 is a schematic configuration diagram of an electronic document decryption apparatus according to one embodiment.
  • FIG. 9 is a functional block diagram of a processing unit of the electronic document decryption apparatus showing functions realized for executing the process of decrypting the electronic document.
  • FIG. 10 is a diagram showing an operation flowchart of a decryption process controlled by a computer program executed on the processing unit of the electronic document decryption apparatus.
  • This electronic document encryption apparatus is configured such that, after a hidden area is set, when a character string or object located before the hidden area or in the middle of the hidden area is edited, the portion to be hidden is positioned after editing. At the same time, the position of the hidden area is corrected.
  • the electronic document encryption device stores a table in which the latest position and size of the concealment area are recorded in association with the position of the concealment area at the time of setting in the predetermined area of the electronic document, thereby editing the electronic document after editing. It is not necessary to reset the hidden area.
  • FIG. 1 is a schematic configuration diagram of an electronic document encryption apparatus according to an embodiment.
  • the electronic document encryption apparatus 1 includes an operation unit 2, a display unit 3, a storage unit 4, a processing unit 5, and an input / output unit 6.
  • the operation unit 2 has an input device such as a keyboard, a mouse, or a touch pad, for example.
  • the operation unit 2 is used by the user to set a concealment area at an arbitrary location of the electronic document displayed on the display unit 3. Then, a signal indicating a region input via the operation unit 2 is passed to the processing unit 5.
  • the operation unit 2 is also used by a user to edit an electronic document. A signal representing a character or the like input via the operation unit 2 is also passed to the processing unit 5.
  • the display unit 3 includes a display device such as a liquid crystal display or a CRT monitor. Then, the display unit 3 displays an electronic document that is a target for setting a hidden area. When the concealment area input via the operation unit 2 is set for the electronic document, the display unit 3 displays the electronic document including the set concealment area. Further, the display unit 3 displays operation buttons or menus for editing the electronic document, such as an icon for setting a hidden area in the electronic document.
  • the storage unit 4 includes, for example, at least one of a semiconductor memory and a magnetic disk device.
  • the storage unit 4 is a computer program such as an electronic document editing application executed by the electronic document encryption apparatus 1, an electronic document to be encrypted, an electronic document encrypted by the electronic document encryption apparatus 1, or the like. Store the data. Then, the storage unit 4 outputs a predetermined program or data to the processing unit 5 in accordance with a control signal from the processing unit 5. The storage unit 4 stores data received from the processing unit 5.
  • the input / output unit 6 acquires from the portable recording medium an electronic document that is a target for setting a hidden area. Further, the input / output unit 6 outputs an electronic document in which a concealment area is set to a portable recording medium.
  • the input / output unit 6 includes an access device or an interface circuit for a portable recording medium such as a CD, a DVD, a floppy disk (registered trademark), or a universal serial bus (USB) memory. Then, the input / output unit 6 reads an electronic document that is a target for setting a concealment area from a portable recording medium attached to the input / output unit 6 and passes the electronic document to the processing unit 5.
  • the input / output unit 6 writes the electronic document set with the concealment area received from the processing unit 5 to a portable recording medium attached to the input / output unit 6. Further, the input / output unit 6 acquires an electronic document that is a target for setting a concealment area through a communication network that complies with a communication standard such as Ethernet (registered trademark), or receives an electronic document in which the concealment area is set as another You may output to an apparatus.
  • the input / output unit 6 includes a communication interface for connecting the electronic document encryption device 1 to a communication network and its control circuit.
  • the processing unit 5 includes one or a plurality of processors and their peripheral circuits.
  • the processing unit 5 executes the electronic document editing application, so that the user operates the electronic document acquired via the input / output unit 6 or read from the storage unit 4 via the operation unit 2. Editable. Further, the processing unit 5 executes a process of concealing part or all of the electronic document in accordance with an instruction from the operation unit 2 for the electronic document. Further, the processing unit 5 controls the entire electronic document encryption apparatus 1.
  • FIG. 2 is a functional block diagram of the processing unit 5 showing functions realized for executing a process of concealing part or all of the electronic document.
  • the processing unit 5 includes a hidden area setting unit 51, an encryption unit 52, a document editing information acquisition unit 53, and a hidden area management unit 54.
  • Each of these units included in the processing unit 5 is a functional module implemented by a computer program executed on a processor included in the processing unit 5.
  • the hidden area setting unit 51 sets an area input by the user via the operation unit 2 as a hidden area. For example, when the user clicks a concealment region setting icon displayed on the display unit 3 using the mouse of the operation unit 2, the processing unit 5 starts the concealment region setting process. Then, after the hidden area setting process is started, the hidden area setting unit 51 operates the coordinates on the screen of the display unit 3 of the upper left point and the lower right point of the hidden area set by the user on the electronic document using the mouse. Obtained from part 2. Note that the concealment area may be set not only in the body of the electronic document but also in any of a header, a footer, a comment area, and a user extension area.
  • the hidden area setting unit 51 determines the position and size of the hidden area on the electronic document from the relationship between the coordinates of the upper left end point and the lower right end point of the hidden area and the position on the display unit 3 of the electronic document. Then, the hidden area setting unit 51 associates the position and size of the hidden area with the area ID number uniquely determined for each hidden area, and records it in the hidden area management table for recording information related to the hidden area.
  • the position of the concealment area is represented by, for example, a combination of a page number, a line number, and the number of characters from the left end in each line.
  • the page number may be omitted.
  • the size of the concealment area is represented by, for example, character point units or the number of characters included in the concealment area in each of the horizontal and vertical directions.
  • the hidden area setting unit 51 stores the hidden area management table in the header, footer, comment area, or user extension area of the electronic document in which the hidden area is set.
  • the hidden area setting unit 51 passes information representing the position and size of the hidden area on the electronic document to the encryption unit 52.
  • the encryption unit 52 encrypts an object such as a character string or an image, a mathematical expression, or a table included in the hidden area set by the hidden area setting unit 51. At that time, when only the character string is included in the concealment area, the encryption unit 52 encrypts the character string included in the concealment area or encrypts the entire concealment area as an image. When one or more objects are included in the hidden area, the encryption unit 52 encrypts the entire hidden area as an image.
  • the encryption unit 52 When encrypting the character string included in the concealment area, the encryption unit 52 creates, for example, a character string in which all characters included in the concealment area are connected in a predetermined order.
  • the encryption unit 52 encrypts the character string by replacing the code of each character included in the character string with another character code according to a predetermined algorithm using a bit string called a key.
  • the encryption unit 52 encrypts a character string included in the hidden area according to a common key method such as Data Encryption Standard (DES) or Advanced Encryption Standard (AES).
  • DES Data Encryption Standard
  • AES Advanced Encryption Standard
  • the encryption unit 52 may encrypt the character string included in the hidden area according to a public key method such as RSA encryption.
  • the predetermined order may be any order as long as the apparatus that decrypts the electronic document encrypted by the electronic document encryption apparatus 1 can know the order.
  • the predetermined order may be arranged in order from the character closest to the beginning of the electronic document in the hidden area, or may be arranged in order from the character closest to the tail of the electronic document in the hidden area.
  • the encryption unit 52 stores the encrypted character string in the header, footer, comment area, or user extension area of the electronic document.
  • the encryption unit 52 stores the encrypted character string in an area on the electronic document that is not printed on the medium such as a user extension area when the electronic document is printed on a medium such as paper. Is preferred.
  • the electronic document encryption device 1 can improve the security of the electronic document.
  • the encryption unit 52 also conceals the character string or object in the concealment area with a document component different from the character string or object contained in the concealment area in order to conceal the information written in the concealment area.
  • the document component is a minimum unit component that can be edited on an electronic document, such as a character and an indivisible object.
  • the encryption unit 52 arranges a graphic object that is painted with a specific color (for example, black or white) or has a pattern such as hatching in the hidden area.
  • the encryption unit 52 may replace each character included in the hidden area with a predetermined character. Further, the encryption unit 52 may replace each character included in the hidden area with a plurality of characters different from the character.
  • the encryption unit 52 may replace each of a predetermined number of two or more characters included in the concealment region with one character different from those characters. In this way, the number of characters different from the number of characters included in the character string in the concealment area is arranged in the concealment area, so that the encryption unit 52 estimates the character string included in the concealment area. To make it more difficult to do.
  • the encryption unit 52 When encrypting the hidden area as an image, the encryption unit 52 converts the hidden area into a bitmap, for example.
  • the encryption unit 52 divides the concealment area into a plurality of blocks, and sets a unique number for each block. For example, the encryption unit 52 divides the concealment region into a total of 12 blocks of 3 vertical ⁇ 4 horizontal, and assigns numbers 1 to 12 to the respective blocks.
  • the encryption unit 52 executes a scramble process for exchanging the position of each block using the encryption key. For this purpose, the encryption unit 52 creates a correspondence table representing the positional relationship between the blocks before and after conversion from the encryption key. For example, assume that the block number before conversion is represented by x and the block number after conversion is represented by y.
  • the block conversion formula corresponding to the scramble processing is expressed by the following formula.
  • the encryption unit 52 may arrange the encrypted image as it is in the hidden area.
  • the encryption unit 52 may store the encrypted image in the header, footer, comment area, or user extension area of the electronic document. Also in this case, the encryption unit 52 stores the encrypted image in an area on the electronic document that is not printed on the medium such as a user extension area when the electronic document is printed on a medium such as paper. Is preferred. Even when the encrypted unit 52 stores the encrypted image in an area on the electronic document different from the hidden area, the encryption unit 52 converts the character string or object in the hidden area to the character string or object included in the hidden area.
  • the encryption unit 52 may provide a pattern for specifying the area where the encryption process has been performed around the encrypted concealment area. Further, the encryption unit 52 may invert the value of a pixel at a predetermined position in each block in order to specify the position of each block. The encryption unit 52 may encrypt the hidden area using another image encryption method.
  • FIGS. 3A to 3C show the original document, the encrypted document in which the concealment area on the original document is painted in black, and the encryption process as an image for the concealment area on the original document, respectively.
  • An example of an encrypted document in which is executed is shown.
  • the original document 300 includes a character string 301 and a table 302.
  • concealment areas 311 and 312 are set in two places in the character string 301 of the original document 300, and a concealment area 313 is set so as to conceal the table 302.
  • the hidden areas 311 to 313 are painted black, and the character strings and tables in the hidden areas are unreadable.
  • the concealment areas 321 to 323 corresponding to the concealment areas 311 to 313 shown in FIG. 3B are encrypted as images.
  • the encryption unit 52 returns an electronic document obtained by encrypting the character string or object included in the set hidden area to the processing unit 5.
  • the processing unit 5 displays the electronic document in which the hidden area is set on the display unit 3. At that time, the processing unit 5 displays the set hidden area together with the original character string or object before being encrypted on the display unit 3 so that the user can edit the character string or object in the hidden area. You may display the outline. Alternatively, the processing unit 5 may make the color or pattern of the original character string or the background of the object before being encrypted different from other parts on the display unit 3 for which the hidden area is set. Further, the processing unit 5 may store the electronic document in which the concealment area is set in a portable recording medium via the input / output unit 6 or store the electronic document in the storage unit 14.
  • the document editing information acquisition unit 53 displays the position and size of the character string or object corrected by the editing work on the electronic document. Obtained from an electronic document editing application. Specifically, the document editing information acquisition unit 53 acquires the number of characters, font size, and position of the character string included in the character string inserted into or deleted from the electronic document from the electronic document editing application. . The document editing information acquisition unit 53 acquires the size and position of an object inserted into the electronic document or deleted from the electronic document from the electronic document editing application. Then, the document editing information acquisition unit 53 passes the position and size of the character string or object corrected in the editing operation on the electronic document to the hidden area management unit 54.
  • the hidden area management unit 54 When the hidden area management unit 54 receives the position and size of the character string or the object on the electronic document corrected by the editing work from the document editing information acquisition unit 53, the hidden area management unit 54 corrects the hidden area based on the position and size. Therefore, the hidden area management unit 54 compares the position of the character string or object corrected in the editing operation on the electronic document with the position of each hidden area stored in the hidden area management table. Then, when the character string or object modified by the editing operation is located before or in the concealment area, the concealment area management unit 54 moves the character string or object to be concealed generated by the modification. Only move the hidden area.
  • the hidden area management unit 54 Moves the concealment area backward by an amount corresponding to the predetermined number of characters. Then, the hidden area management unit 54 records the current position of the hidden area after movement in the hidden area management table.
  • a line break may occur in the middle of a hidden character string or object by editing the electronic document.
  • the character string to be concealed may be divided into a part that remains without line breaks and a part that moves to the next line after line breaks.
  • the character string to be concealed may be divided into two parts before and after the inserted character string. Therefore, when the character string or object concealed by the concealment area is divided, the concealment area management unit 54 also divides the concealment area in accordance with the front part and the rear part of the character string or object.
  • the hidden area setting unit 51 may divide the hidden area for each document component included in the hidden area.
  • the electronic document encryption apparatus 1 determines the correspondence between each part of the encrypted character string or object included in the concealment area and each division area. Need to record.
  • the concealment area management unit 54 reconstructs the original concealment area by recombining the divided areas, and for each divided area, the initial setting position of the concealment area, the position after movement, and the division area Is recorded in the hidden area management table.
  • FIG. 4A and FIG. 4B are diagrams showing examples of the concealment area set in the electronic document and the concealment area after division when the electronic document is edited after the concealment area is set. It is.
  • one hidden area 401 is set in the electronic document 400.
  • the upper left point of the hidden area 401 is the third line from the top and the fifth character from the left
  • the lower right end point of the hidden area 401 is the fourth line from the top and the sixth character from the left.
  • Each character included in the concealment area is replaced with another symbol “ ⁇ ”.
  • FIG. 4A one hidden area 401 is set in the electronic document 400.
  • the upper left point of the hidden area 401 is the third line from the top and the fifth character from the left
  • the lower right end point of the hidden area 401 is the fourth line from the top and the sixth character from the left.
  • Each character included in the concealment area is replaced with another symbol “ ⁇ ”.
  • the character string to be concealed in the concealment area 401 is the third line and It is divided into the right end of the fourth row and the left end of the fourth and fifth rows. Therefore, the hidden area management unit 54 also divides the hidden area 401 into hidden areas 411 to 414. As described above, even if a line break occurs in the middle of a character string to be concealed by editing the electronic document, or another character string is inserted in the middle of the character string, the electronic document encryption apparatus 1 The character string to be concealed can be concealed accurately.
  • FIG. 5 is a diagram showing an example of a concealment area management table corresponding to the concealment area 401 shown in FIGS. 4 (a) and 4 (b).
  • the hidden area management table 500 has information related to one hidden area for each row.
  • the hidden area management table 500 records the storage positions of data such as the area ID number, the number of divisions, the coordinates before movement, the coordinates after movement, the area size, and the encrypted character string in order from the left column.
  • the number of divisions is the number of divided areas created by dividing the hidden area. Therefore, if the concealment area is not divided, the division number is 1.
  • the pre-movement coordinates represent the position of the hidden area on the electronic document at the first setting time of the hidden area.
  • the coordinates before movement represent the position on the electronic document for each division area.
  • the post-movement coordinate represents the position of the hidden area on the electronic document in the latest state of the electronic document. If the concealment area is divided, the post-movement coordinates represent positions on the electronic document for each division area.
  • the area size represents the size of the hidden area. When the hidden area is divided, the area size represents the size of each divided area.
  • the hidden area information 501 stored in the first line of the hidden area management table 500 is information related to the hidden area 401 shown in FIGS. 4 (a) and 4 (b).
  • the item of the number of divisions in the hidden area information 501 indicates that the hidden area 401 is divided into four divided areas.
  • the item of the pre-movement coordinate in the hidden area information 501 indicates that the position 511 of the divided area 411 at the beginning of setting the hidden area 401 is the third line from the top and the fifth character from the left, for example.
  • the post-movement coordinate item of the hidden area information 501 indicates that the current position 521 of the divided area 411 is the third line from the top and the sixth character from the left.
  • the area size item of the hidden area information 501 indicates that, for example, the size 531 of the divided area 411 is 10 points in both the horizontal direction and the vertical direction.
  • the item of the storage location of the hidden area information 501 indicates that the code obtained by encrypting the character string included in the hidden area 401 is arranged first in the user extension area.
  • FIG. 6 shows an operational flowchart of encryption processing when a hidden area is set, which is controlled by a computer program executed on the processing unit 5 of the electronic document encryption apparatus 1.
  • the processing unit 5 acquires an electronic document that is a target for setting a concealment area via the input / output unit 6 or reads it from the storage unit 4.
  • the processing unit 5 activates an electronic document editing application and causes the display unit 3 to display the electronic document.
  • the processing unit 5 starts an encryption process.
  • the concealment area setting unit 51 of the processing unit 5 determines the concealment area on the electronic document based on the area input by the user via the operation unit 2 (step S101). Then, the hidden area setting unit 51 stores information on the position and size of the hidden area in the hidden area management table (step S102). The hidden area setting unit 51 passes information on the position and size of the hidden area to the encryption unit 52 of the processing unit 5. The encryption unit 52 encrypts the character string or object included in the hidden area (step S103). When encrypting the character string included in the hidden area, the encryption unit 52 stores the encrypted character string in the header, footer, comment area, or user extension area of the electronic document.
  • the encryption unit 52 replaces the character string or object in the hidden area with another object so that the character string or object in the hidden area is hidden on the display unit 3.
  • the encryption unit 52 may encrypt the hidden area as an image.
  • the processing unit 5 outputs the electronic document in which the character string and the object in the hidden area are hidden via the input / output unit 6 (step S104). Further, the processing unit 5 displays the electronic document on the display unit 3. Further, the processing unit 5 may store the electronic document in the storage unit 4. Thereafter, the processing unit 5 ends the encryption process.
  • FIG. 7 shows an operational flowchart of a hidden area correction process when an electronic document in which a hidden area is set, which is controlled by a computer program executed on the processing unit 5 of the electronic document encryption apparatus 1, is edited.
  • the processing unit 5 starts the hidden area correction process.
  • the document editing information acquisition unit 53 of the processing unit 5 acquires the position and size of the character string or object corrected by editing the electronic document from the electronic document editing application being executed on the processing unit 5 ( Step S201).
  • the document editing information acquisition unit 53 passes the position and size of the character string or object corrected in the editing operation on the electronic document to the hidden area management unit 54 of the processing unit 5.
  • the concealment area management unit 54 determines whether or not the character string or object that should be concealed by the concealment area that has already been set is moved by the character string or object that has been corrected by the editing operation (step S202). . If the character string or object to be concealed does not move due to the editing operation (step S202-No), the processing unit 5 ends the concealment area correction process.
  • the concealment area management unit 54 determines whether the character string or object included in the concealment area is divided in the middle. (Step S203). When the character string or object included in the concealment area is not divided (step S203—No), the concealment area management unit 54 moves the concealment area by the amount of movement of the character string or object to be concealed that has occurred due to the editing operation. To do. Then, the hidden area management unit 54 records the current position of the hidden area after the movement in the hidden area management table (step S204).
  • step S203 when the character string or object included in the concealment area is divided in the middle (step S203—Yes), the concealment area management unit 54 divides the character string or object into the front part and the rear part. Accordingly, the concealment area is divided (step S205).
  • the hidden area management unit 54 records the current position and size of each divided area in the hidden area management table (step S206).
  • step S204 or S206 the processing unit 5 outputs the electronic document in which the position of the hidden area is corrected via the input / output unit 6 (step S207). Further, the processing unit 5 displays the electronic document on the display unit 3. Further, the processing unit 5 may store the electronic document in the storage unit 4. Thereafter, the processing unit 5 ends the hidden area correction process.
  • the processing unit 5 executes the processes in steps S201 to S206 described above for each concealment area.
  • step S207 the processing unit 5 outputs the electronic document corrected for all the concealment areas via the input / output unit 6.
  • FIG. 8 is a schematic configuration diagram of an electronic document decryption apparatus according to one embodiment. As illustrated in FIG. 8, the electronic document decryption apparatus 11 includes a display unit 12, an input unit 13, a storage unit 14, and a processing unit 15.
  • the display unit 12 includes a display device such as a liquid crystal display or a CRT monitor.
  • the display unit 12 displays the electronic document in which the hidden area is set or the electronic document in which the character string or the object included in the hidden area is decoded by the processing unit 15.
  • the input unit 13 acquires an electronic document in which a hidden area is set, and passes the electronic document to the processing unit 15.
  • the input unit 13 includes an access device or an interface circuit for a portable recording medium such as a CD, a DVD, a floppy disk (registered trademark), or a USB memory. Then, the input unit 13 reads an electronic document in which a concealment area is set from a portable recording medium attached to the input unit 13 and passes it to the processing unit 15. Further, the input unit 13 may acquire an electronic document in which a concealment area is set through a communication network according to a communication standard such as Ethernet (registered trademark). In this case, the input unit 13 includes a communication interface for connecting the electronic document decryption apparatus 11 to a communication network and its control circuit.
  • the storage unit 14 includes, for example, at least one of a semiconductor memory and a magnetic disk device.
  • the storage unit 4 is a computer program such as an electronic document editing application executed by the electronic document decryption device 11, an electronic document encrypted by the electronic document encryption device 1, or an electronic data decrypted by the electronic document decryption device 11. Stores data such as documents.
  • the storage unit 14 outputs a predetermined program or data to the processing unit 15 in accordance with a control signal from the processing unit 15.
  • the storage unit 14 stores data received from the processing unit 15.
  • the processing unit 15 has one or a plurality of processors and their peripheral circuits. Then, the processing unit 15 decrypts the electronic document in which the hidden area is set. Further, the processing unit 15 controls the entire electronic document decryption apparatus 11.
  • FIG. 9 is a functional block diagram of the processing unit 15 showing functions realized for executing the process of decrypting the electronic document.
  • the processing unit 15 includes a concealed area restoration unit 61, a decoding unit 62, and a decoded information rearrangement unit 63.
  • Each of these units included in the processing unit 15 is a functional module implemented by a computer program executed on a processor included in the processing unit 15.
  • the hidden area restoration unit 61 recombines the divided areas.
  • the hidden area restoration unit 61 refers to the hidden area management table and acquires the pre-movement coordinates and sizes corresponding to the respective divided areas.
  • the hidden area restoration unit 61 rearranges the divided areas in accordance with the corresponding coordinates and size before movement in the memory area of the processing unit 15 secured separately from the electronic document to be decrypted, and reconfigures the divided areas as one area. By combining, the hidden area is restored.
  • the hidden area restoration unit 61 passes the restored hidden area to the decoding unit 62.
  • the decryption unit 62 decrypts the character string or object included in the hidden area.
  • the decrypting unit 62 decrypts the encrypted character string using the decryption algorithm and the key corresponding to the algorithm used in the encryption processing. To do.
  • the concealment area is encrypted as an image
  • the decryption unit 62 performs a descrambling process on each block included in the encrypted image, thereby returning the block to the original block position. Reconstruct the corresponding original image.
  • the decryption unit 62 uses the expression (1) for converting the encryption key and the block position when the scramble process is executed, and the position of the block after the scramble process is y in the encryption area.
  • the original position x of the block can be determined. Then, the decryption unit 62 can reconstruct the original image by moving each block in the encryption area to the obtained original block position. The decryption unit 62 passes the decrypted character string or object to the decryption information rearrangement unit 63.
  • the decryption information rearrangement unit 63 rearranges the decrypted character string and object at the current position of the hidden area with reference to the hidden area management table. For example, when a character string included in the concealment area is decrypted, the decryption information rearrangement unit 63 returns each character included in the character string to the original position according to the order in which the characters are aligned. Then, the decryption information rearrangement unit 63 inserts the decrypted character string or object into the concealed area specified by the item of the post-movement position in the concealment area management table, or the document structure for information concealment Replace with an element.
  • the decoding information rearrangement unit 63 refers to the area size item of the hidden area management table and calculates the number of characters or the size or number of objects included in each divided area. Then, based on the calculated number of characters or the size or number of objects, the decoding information rearrangement unit 63 determines the number of character strings or object parts or objects included in each divided region. For each divided area, the decryption information rearrangement unit 63 inserts the decoded character string or object included in the divided area at the position of the divided area specified by the item of the moved position in the concealed area management table. Replace with encrypted image or document component for information hiding.
  • the decryption information rearrangement unit 63 reconstructs an electronic document displaying the same content as the original electronic document.
  • the decryption information rearrangement unit 63 passes the reconstructed electronic document to the processing unit 15.
  • the processing unit 15 causes the display unit 13 to display the reconstructed electronic document. Further, the processing unit 15 stores the reconstructed electronic document in the storage unit 14.
  • the processing unit 15 may display the decrypted character string or object in a window separate from the window where the decrypted electronic document is displayed on the display unit 13.
  • the decryption information rearrangement unit 63 returns to the processing unit 15 document data in which the character string or object included in the hidden area is arranged according to the state at the time of setting the hidden area.
  • the hidden area on the electronic document is displayed on the display unit 13 in the same state as before being decrypted.
  • the processing unit 15 stores the decrypted character string or object in the header, footer, comment area, or user extension area of the electronic document in which the hidden area is set, and stores the electronic document in the storage unit 14. Good.
  • FIG. 10 shows an operational flowchart of a decryption process controlled by a computer program executed on the processing unit 15 of the electronic document decryption apparatus 11.
  • the processing unit 15 acquires an electronic document in which a hidden area is set
  • the processing unit 15 starts a decryption process.
  • the hidden area restoration unit 61 of the processing unit 15 refers to the item of the number of divisions in the hidden area management table to determine whether or not the hidden area is divided (step S301).
  • step S301—No the processing unit 15 shifts the control to step S303.
  • the hidden area restoring unit 61 restores the hidden area by recombining the divided areas (step S302). Then, the hidden area restoration unit 61 passes the restored hidden area to the decoding unit 62 of the processing unit 15.
  • the decryption unit 62 decrypts the character string or object included in the hidden area (step S303). Then, the decryption unit 62 passes the decrypted character string or object to the decryption information rearrangement unit 63 of the processing unit 15. The decryption information rearrangement unit 63 reconstructs the original electronic document by rearranging the decrypted character string or object to the current position of the hidden area (step S304). Then, the decryption information rearrangement unit 63 returns the reconstructed electronic document to the processing unit 15. The processing unit 15 displays the reconstructed electronic document received from the decryption information rearrangement unit 63 on the display unit 13 (step S305). The processing unit 15 may store the reconstructed electronic document in the storage unit 14.
  • the processing unit 15 ends the decoding process. If a plurality of concealment areas are set for one electronic document, the processing unit 15 repeats the processes of steps S301 to S304 for each concealment area. Then, in step S ⁇ b> 305, the processing unit 15 displays on the display unit 13 the electronic document in which all the concealment areas have been decoded and reconstructed.
  • the electronic document encryption apparatus after a hidden area is set, a character string or an object located before the hidden area or in the middle of the hidden area is edited. In this case, the hidden area is moved in accordance with the position of the character string or object to be hidden after the editing.
  • the concealment area when a character string or object included in the concealment area is divided by editing the electronic document, the concealment area is also a part of the front side of the divided character string or object. And split to fit the rear part.
  • the electronic document encryption apparatus records the concealed area at the time of setting in a recoverable manner by managing the position and size of the concealed area after editing in association with the position of the concealed area at the time of setting.
  • an electronic document decryption apparatus that decrypts an electronic document in which a concealment area is set by the electronic document encryption apparatus restores the concealment area at the time of setting with reference to a concealment area management table stored in the electronic document. Therefore, this electronic document decryption apparatus decrypts a character string or an object in the hidden area even if the hidden area set in the electronic document is divided by editing the electronic document after the setting. Electronic documents can be reconstructed.
  • a computer program that causes a computer to realize the functions of the hidden area setting unit, the encryption unit, the document editing information acquisition unit, and the hidden area management unit included in the processing unit of the electronic document encryption apparatus is readable by the computer. It may be provided in a recorded form on a medium.
  • a computer program that causes a computer to realize the functions of the hidden area restoration unit, the decoding unit, and the decryption information rearrangement unit included in the processing unit of the electronic document decryption apparatus is provided in a form recorded on a computer-readable medium. May be.

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  • General Physics & Mathematics (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
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Abstract

L'invention concerne un dispositif de codage de document électronique comprenant un élément opérationnel pour éditer un document électronique exprimé sous forme de données électroniques, et un élément de traitement pour fixer une zone de dissimulation pour dissimuler une chaîne de caractères ou un objet inclus dans au moins une partie du document électronique. L'élément de traitement réalise une fonction de fixation d'une zone du document électronique saisi via l'élément opérationnel en tant que zone de dissimulation et de stockage d'une table dans laquelle la position et la taille de la zone de dissimulation du document sont enregistrées, dans une zone prédéterminée du document, une fonction de codage de la chaîne de caractères ou de l'objet inclus dans la zone de dissimulation, une fonction d'acquisition de la position de la chaîne de caractères ou de l'objet inséré ou supprimé par l'édition si le document est édité après la fixation de la zone de dissimulation, et une fonction de correction de la position de la zone de dissimulation en fonction d'un décalage de la chaîne ou de l'objet à dissimuler lorsque sa position varie sur la base d'un rapport entre la position mentionnée et la position de la zone de dissimulation, et l'enregistrement de la position corrigée de la zone de dissimulation dans la table
PCT/JP2009/055483 2009-03-19 2009-03-19 Dispositif de codage de document électronique, procédé de codage de document électronique, programme de codage de document électronique et dispositif de décodage de document électronique WO2010106669A1 (fr)

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PCT/JP2009/055483 WO2010106669A1 (fr) 2009-03-19 2009-03-19 Dispositif de codage de document électronique, procédé de codage de document électronique, programme de codage de document électronique et dispositif de décodage de document électronique

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PCT/JP2009/055483 WO2010106669A1 (fr) 2009-03-19 2009-03-19 Dispositif de codage de document électronique, procédé de codage de document électronique, programme de codage de document électronique et dispositif de décodage de document électronique

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016012271A (ja) * 2014-06-30 2016-01-21 株式会社エクサ 機密情報隠蔽システム
JP2022137950A (ja) * 2021-03-09 2022-09-22 株式会社ジェーシービー 情報処理装置、情報処理方法及びコンピュータープログラム

Citations (3)

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Publication number Priority date Publication date Assignee Title
JP2003203005A (ja) * 2002-01-08 2003-07-18 Sony Corp 情報処理システム、情報処理装置および方法、記録媒体、並びにプログラム
JP2006133870A (ja) * 2004-11-02 2006-05-25 Sharp Corp レイアウト装置、コンピュータプログラム、及び記録媒体
JP2008124971A (ja) * 2006-11-15 2008-05-29 Research Organization Of Information & Systems デジタルコンテンツ登録配信装置、システム及び方法

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003203005A (ja) * 2002-01-08 2003-07-18 Sony Corp 情報処理システム、情報処理装置および方法、記録媒体、並びにプログラム
JP2006133870A (ja) * 2004-11-02 2006-05-25 Sharp Corp レイアウト装置、コンピュータプログラム、及び記録媒体
JP2008124971A (ja) * 2006-11-15 2008-05-29 Research Organization Of Information & Systems デジタルコンテンツ登録配信装置、システム及び方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016012271A (ja) * 2014-06-30 2016-01-21 株式会社エクサ 機密情報隠蔽システム
JP2022137950A (ja) * 2021-03-09 2022-09-22 株式会社ジェーシービー 情報処理装置、情報処理方法及びコンピュータープログラム

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