JP2007286663A - Image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily prevent any secret section in a document from being known. <P>SOLUTION: An image formation apparatus 10A receives and stores document data where encrypted data and tag information showing a means for decoding the encrypted data are associated with each other. When the output instruction of a document shown by the stored document data is input, the image formation apparatus 10A extracts the tag information added to the encrypted data in the document data. When the tag information is an HW key, the image formation apparatus 10A acquires a common key from a mounted HW key 60, and decodes the encrypted data added to the tag information by the acquired common key. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for restricting image formation for a confidential portion in a document.

As disclosed in Patent Documents 1 and 2, there is a technique for restricting image formation only for a confidential portion in a document when forming an image of a confidential document.
When the authentication information of the person who requested the output of the received color document is input, the image processing apparatus disclosed in Patent Document 1 compares the authentication information stored in the storage unit and the authentication information does not match In this case, the output of the specific color portion of the received color document is stopped. According to this image processing apparatus, if the color of the confidential portion is set to a specific color, the specific color portion is not output unless the person who has requested the output of the document is authenticated. Therefore, image formation of the confidential portion is limited. It will be.
Further, the image forming apparatus disclosed in Patent Document 2 transmits the input user ID and password to the server apparatus. When the server device authenticates the user with the user ID and password, the user attribute is sent to the image forming apparatus. The image forming apparatus controls printing of the document according to the security policy set for the document and the sent user attribute. According to this image forming apparatus, it is possible to limit image formation for a specific part of a document for a specific user.
JP 2004-297758 A JP 2004-192610 A

  The image processing apparatus disclosed in Patent Document 1 compares the input authentication information with the authentication information stored in advance in the image processing apparatus, and authenticates the person who requested the document output. Yes. The image forming apparatus disclosed in Patent Document 2 communicates with an external server device to authenticate a user. However, if authentication is performed by only one authentication unit as described above, the weak point of the authentication unit may be known, and information may be output illegally. In Patent Documents 1 and 2, since the document itself is sent to the image forming apparatus in plain text, there is a possibility that a confidential part may be stolen by looking at the document stored in the image forming apparatus.

  The present invention has been made under the above-described background, and an object of the present invention is to provide a technique for preventing a secret portion in a document from being easily known.

  In order to solve the above-described problems, the present invention provides a plurality of decryption key acquisition means, each having a different decryption key for decrypting encrypted image information, and an encryption in which image information is encrypted with an encryption key. Extracted from the data associated with the encrypted image information and the tag information representing the acquisition means of the decryption key for decrypting the encrypted image information, and extracted by the extraction unit A decryption key acquisition unit corresponding to the acquisition unit represented by the tag information extracted by the extraction unit among the plurality of decryption key acquisition units, as a decryption key for decrypting the encrypted image information associated with the tag information And decrypting the encrypted image information with the obtained decryption key, and generating an image represented by the image information according to the image information obtained by the decryption by the decrypting unit. To provide an image processing apparatus having a means.

  Further, the present invention provides a plurality of encryption key acquisition means each having a different means for acquiring an encryption key for encrypting image information, a display means for displaying an image, an operation means having a plurality of operators, In response to an instruction given to the operation means of the operation means, an area designation means for designating an area in the image displayed on the display means, and a plurality of the plurality of instructions according to an operation given to the operation means of the operation means A selection means for selecting one or a plurality of encryption key acquisition means from among the encryption key acquisition means, an encryption key is acquired by the encryption key acquisition means selected by the selection means, and the region specifying means is obtained by the acquired encryption key. Generating data including encryption means for encrypting the image in the area designated by the tag, tag information representing the encryption key acquisition means selected by the selection means, and information encrypted by the encryption means Data generator To provide an image processing apparatus having and.

  According to the present invention, it is possible to prevent a secret part in a document from being easily known. In addition, since the encryption means can be arbitrarily selected from a plurality of encryption means, and the document can be encrypted by combining the encryption means, the output of confidential information can be flexibly limited.

[Configuration of the embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a system according to the present embodiment. The system shown in FIG. 1 is built in a corporate office and includes image forming apparatuses 10A to 10D, PCs 20A and 20B, a server apparatus 30, a communication network 40, IC cards 50A to 50D, and an HW key 60.

  As shown in FIG. 2, the PC (Personal Computer) 20A includes a CPU 202, a ROM 203, a RAM 204, a storage unit 205, an input unit 206 including a keyboard and a mouse, and a display device that displays various messages and menus. A unit 207, an IC card reader 212, and a HW key IF 213 are provided, and each unit exchanges various types of data between the units via a connected bus 201.

  The IC card reader 212 includes a card slot into which the IC cards 50A to 50D are inserted. The IC card reader 212 functions as an interface for acquiring information stored in the IC card inserted into the card slot, and acquires information stored in the inserted IC card. The HW (Hardware) key IF (Interface) unit 213 includes a connector to which the HW key 60 is attached. The HW key IF 213 functions as an interface for acquiring information stored in the HW key 60 attached to the connector, and acquires information stored in the HW key 60. The PC 20B has the same configuration as the PC 20A, but is different from the PC 20A in that it does not include the HW key IF 213.

  The PC 20A is arranged in different departments such as a corporate development department and the PC 20B is a sales department. The PCs 20 </ b> A and 20 </ b> B are connected to the communication network 40 and can communicate with various devices connected to the communication network 40. The PCs 20A and 20B store a word processor program (hereinafter abbreviated as a word processor program) that realizes a function for creating / editing a document and a function for instructing the image forming apparatus to output a document. When this program is executed by the PCs 20A and 20B, a document creation / editing function and a function for instructing an image forming apparatus connected to the communication network 40 to output a document are realized. And editing. In the present embodiment, a plurality of PCs can be connected to the communication network 40, but only the PC 20A and the PC 20B are illustrated in order to prevent the drawing from becoming complicated.

  The IC cards 50A to 50D are IC cards possessed by employees belonging to the development department and sales department described above. In this embodiment, manager A belonging to the development department, development department employee B belonging to the development department, manager C belonging to the sales department, sales department employee D also belonging to the sales department, and outsourcing to the development department The working outsourcer E uses the system shown in FIG. 1, but the IC card is owned by someone other than the outsourced employee E. Manager A has an IC card 50A, development department employee B has an IC card 50B, manager C has an IC card 50C, and sales department employee D has an IC card 50D. As shown in FIG. In addition, a user identifier for uniquely identifying a user possessing the IC card, a department name to which the user belongs, a title of the user, and the like are stored. The IC card possessed by manager A and manager C stores a public key used when encrypting a document created by PCs 20A and 20B.

  The HW (HardWare) key 60 includes a nonvolatile memory, and stores a common key used when encrypting / decrypting a document created by the PCs 20A and 20B.

  The image forming apparatuses 10 </ b> A to 10 </ b> D are so-called multifunction machines having a copying function, an image forming function, a FAX function, and the like. FIG. 4 is a block diagram showing a configuration of a main part of the image forming apparatus 10A among the image forming apparatuses 10A to 10D according to the embodiment of the present invention. As shown in FIG. 4, each unit of the image forming apparatus 10 </ b> A is connected to the bus 101, and data is exchanged between each unit via the bus 101.

  The image input unit 108 includes a scanner mechanism that optically reads a document and an ADF (Auto Document Feeder) that transports the document to the scanner mechanism. The documents set in the ADF are conveyed one by one on the platen glass provided in the scanner mechanism. The scanner mechanism irradiates the document conveyed on the platen glass by the ADF with light. Then, the light reflected by the document is read by a CCD (Charge Coupled Device), and image data representing the read document is generated. This image data is stored in the storage unit 105.

  The input unit 106 includes various keys such as a numeric keypad and an arrow key for operating the image forming apparatus 10A. When the user operates these keys, various instructions and information are input to the image forming apparatus 10A, and various settings of the image forming apparatus 10A are performed. The display unit 107 includes, for example, a display device such as a liquid crystal display, and displays a menu screen and various messages for operating the image forming apparatus 10A under the control of the CPU 102.

  The communication unit 110 is connected to the communication network 40. The communication unit 110 functions as a communication interface that performs communication via the communication network 40, and exchanges various data with the PCs 20 </ b> A and 20 </ b> B and the server device 30 under the control of the CPU 102.

  The image processing unit 111 performs image processing such as gradation correction and screen processing on the image represented by the input image data. Then, image data of each color image of Y (Yellow), M (Magenta), C (Cyan), and K (black) is generated from the image-processed image and output to the image forming unit 109.

  The image forming unit 109 includes an image forming engine (not shown) that forms a toner image on a recording sheet by electrophotography. This image forming engine employs an intermediate transfer system, and includes an image forming unit that forms toner images of colors of Y (Yellow), M (Magenta), C (Cyan), and K (black). Each image forming unit forms an electrostatic latent image on the photoconductor according to input image data, and then attaches toner on the photoconductor to form toner images of each color of YMCK. Then, after the toner image is transferred to the intermediate transfer belt, the toner image transferred to the intermediate transfer belt is transferred to the recording sheet conveyed from the paper tray. The toner image transferred to the recording sheet is fixed by applying heat and pressure, and then the recording sheet on which the toner image is formed is discharged out of the image forming apparatus.

  The IC card reader 112 includes a card slot into which the IC cards 50A to 50D are inserted. The IC card reader 112 functions as an interface for acquiring information stored in the IC card inserted into the card slot, and acquires information stored in the inserted IC card.

  The HW key IF 113 includes a connector to which the HW key 60 is attached. The HW key IF 113 functions as an interface for acquiring information stored in the HW key 60 attached to the connector, and acquires information stored in the HW key 60.

  The storage unit 105 includes a hard disk device, and stores image data generated by the image input unit 108 and various data received by the communication unit 110.

  The ROM 103 stores a control program executed by the CPU 102. The CPU 102 reads out the control program stored in the ROM 103 and executes the control program using the RAM 104 as a work area. When the control program is executed by the CPU 102, each part of the image forming apparatus is controlled by the CPU 102, and a copying function, an image forming function for forming an image on a recording sheet according to received data, a FAX function, and a function for communicating with the server device 30. The image forming apparatus operates as a so-called multifunction machine.

  The configuration of the image forming apparatus 10B is the same as that of the image forming apparatus 10A, but is different from the image forming apparatus 10A in that the HW key IF 113 is not provided. The configuration of the image forming apparatus 10C is different from the image forming apparatus 10A in that it does not include the IC card reader 112 and the HW key IF 113, and the configuration of the image forming apparatus 10D includes the IC card reader 112 and the HW key IF 113. The image forming apparatus 10A is different from the image forming apparatus 10A in that it does not have a communication function with the server device 30.

  The server device 30 connected to the communication network 40 is a server device including a CPU, a ROM, a RAM, a storage device, a communication interface, and the like. When a program stored in the ROM and a program stored in the storage device are executed by the CPU, each part of the server device is controlled by the CPU, and the server device 30 includes various devices connected to the communication network 40 and A function to perform communication is realized. In addition, the server device 30 stores the user identifiers of the manager A and the manager C, and the secret key used when decrypting the document encrypted with the public key stored in the IC cards 50A and 50C. Upon receiving the user identifier transmitted from the image forming apparatus, the server device 30 transmits the stored secret key to the image forming apparatus that has transmitted the user identifier when the received user identifier is stored.

[Operation of the embodiment]
Hereinafter, the operation of this embodiment will be described.

[Operation when creating a document]
First, an operation when creating a document according to the present embodiment on a PC will be described.
First, the manager A inserts the IC card 50A into the IC card reader 212 of the PC 20A and attaches the HW key 60 to the HW key IF 213. Then, the PC 20A is operated to instruct the activation of the word processor program. When the PC 20A is instructed to start the word processor program, the PC 20A starts the stored word processor program. When the word processor program is activated by the PC 20A, as illustrated in FIG. 5, a window having various toolbars such as a text input area and a menu item toolbar is displayed on the display unit 207 of the PC 20A. When the window illustrated in FIG. 5 is displayed, the manager A operates the PC 20A and, as illustrated in FIG. 6, the document including the graphic 1A, table 1B, customer information 1C, employee information 1D, non-confidential information 1E, etc. Create

  Next, the manager A follows the security policy predetermined in the company using the system shown in FIG. 1 for each element of the graphic 1A, the table 1B, the customer information 1C, the employee information 1D, and the non-confidential information 1E in the document. Encrypt each element. Specifically, for example, when the security policy is defined for the document illustrated in FIG. 6 as illustrated in FIG. 7, the manager A operates the PC 20A to display the graphic 1A as illustrated in FIG. After specifying the area that contains, click the "Encryption" part displayed on the toolbar. When this operation is performed, the window shown in FIG. 9 is displayed on the display unit 207. In the window shown in FIG. 9, the manager A clicks the password check box 2A to select a means to be used when encrypting / decrypting the specified area, and a text box 2D for entering the password. The common password (for example, “ABC”) notified only to the person in the development department is input. Thereafter, when the manager A performs an operation of clicking an OK button in the window, the input password is used as a common key for encrypting / decrypting the document, and the figure 1A is encrypted.

  The manager A operates the PC 20A to designate the area of Table 1B, and then performs an operation of clicking the “encryption” portion displayed on the tool bar to display the window shown in FIG. The manager A clicks the check box 2B of the IC card in the window shown in FIG. Thereafter, when manager A performs an operation of clicking an OK button in the window, the public key stored in IC card 50A inserted in IC card reader 212 is read out, and the read public key is used. Table 1B is encrypted.

  Manager A operates PC 20A to designate the area of customer information 1C, and then performs an operation of clicking the “encryption” portion displayed on the toolbar. The manager A clicks the check box 2C of the HW key in the window shown in FIG. Thereafter, when the manager A performs an operation of clicking the OK button in the window, the common key stored in the HW key 60 attached to the HW key IF 213 is read out, and the customer is read by the read common key. Information 1C is encrypted.

  The manager A operates the PC 20A to designate the area of the employee information 1D, and then performs an operation of clicking the “encryption” portion displayed on the toolbar. The manager A clicks the check box 2B for the IC card and the check box 2C for the HW key in the window shown in FIG. Thereafter, when manager A performs an operation of clicking an OK button in the window, the public key stored in IC card 50A is read and the common key stored in HW key 60 is read. The employee information 1D is encrypted with the public key read from the IC card 50A, and further encrypted with the common key read from the HW key 60.

  If the structure of the document encrypted by the above operation is schematically shown, the graphic 1A, the table 1B, the customer information 1C, and the employee information 1D are encrypted as shown in FIG. Then, tag information 3 representing the means checked in the window shown in FIG. 9, that is, means used for encryption / decryption, is added to each encrypted element. Note that tag information is not added to the non-confidential information 1E because it is not encrypted.

  Thereafter, when the manager A performs an operation for saving the document, document data representing the encrypted document is stored in the storage unit 205 of the PC 20A.

[Operation when a document is displayed on a PC]
Next, an operation for displaying a document created by the above-described operation on the display unit 207 of the PC 20A or PC 20B will be described.

(Operation when manager A in the development department displays a document on PC 20A)
First, when the manager A in the development department displays a document on the PC 20A, the manager A first operates the PC 20A to start the word processor program and then opens the document data. When an operation for opening the document data is performed, the PC 20A analyzes the document data and searches the tag information 3 from the data to determine whether or not there is encrypted data in the document data ( FIG. 18: Step SA1). Here, since there is tag information 3 in the document data, YES is determined in step SA1.

  Next, the PC 20A analyzes the document data and extracts tag information 3 in the document data (step SA2). Here, first, tag information “password” added to the encrypted data of the graphic 1A is extracted. Next, when the extracted tag information is “password” (step SA3: YES), the PC 20A displays the window shown in FIG. 11 on the display unit 207 and prompts the user of the PC 20A to input the password (FIG. 19: Step SB1). Here, when the manager A inputs the common password “ABC” notified only to the person in the development department and clicks the OK button (step SB2; YES), the PC 20A displays the tag information “password”. ”And the password“ ABC ”input are stored in the RAM 204 in association with each other (step SB3).

  Since the tag information extracted in step SA2 is only the password, the PC 20A next generates an image of the document represented by the document data. Specifically, decryption of encrypted data and image generation are performed (step SA9). The PC 20A first extracts the encrypted data of the graphic 1A and the tag information “password” attached to the graphic 1A. Next, the PC 20A reads the password “ABC” stored in the RAM 204 in association with the “password”, and attempts to decrypt it using the password “ABC” read from the encrypted data of the graphic 1A. Here, the password “ABC” stored in the RAM 204 is the password “ABC” used when encrypting the graphic 1A, that is, the common key used when encrypting the graphic 1A. Is decoded, and an image of the graphic 1A is generated.

  Next, the PC 20A determines whether or not the decryption process has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “IC card” added to the encrypted table 1B is extracted. Next, when the extracted tag information is “IC card” (step SA5: YES), the PC 20A determines whether an IC card is inserted in the IC card reader 212 (FIG. 20: step SC1). Here, since the IC card 50A is inserted in the IC card reader 212 (step SC1; YES), the PC 20A acquires the user identifier “A001” stored in the IC card 50A (step SC2). The user identifier is transmitted to server device 30 by controlling communication unit 210 (step SC3). When the transmitted user identifier is received by the server device 30, the server device 30 determines whether or not the received user identifier is stored. If the received user identifier is stored, the stored secret key is transmitted to the PC 20A. Here, since the server device 30 stores the user identifier “A001”, the server device 30 transmits the stored secret key to the PC 20A. When the transmitted secret key is received by communication unit 110 of PC 20A (step SC4; YES), PC 20A associates tag information “IC card” with the received secret key and stores them in RAM 204 (step SC5). ).

  Since the tag information extracted in step SA2 is only the IC card, the PC 20A next performs the process of step SA9. The PC 20A extracts the encrypted data of Table 1B and the tag information “IC card” added to the data of Table 1B. Then, the PC 20 reads the secret key stored in the RAM 204 in association with the “IC card”, and tries to decrypt the data in Table 1B encrypted with the public key, using the read secret key. Here, the secret key stored in the RAM 204 is a secret key that is paired with the public key used when encrypting Table 1B, that is, a secret key used when decrypting data encrypted with the public key. Therefore, the data in Table 1B is decoded, and the image in Table 1B is generated.

  Next, the PC 20A determines whether or not the decryption process has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “HW key” added to the encrypted customer information 1C is extracted. Next, when there is a “HW key” in the extracted tag information (step SA7; YES), the PC 20A determines whether or not the HW key 60 is attached to the HW key IF 213 (FIG. 21: step SD1). Here, since the HW key 60 is attached to the HW key IF 213 (step SD1; YES), the PC 20A acquires the common key stored in the HW key 60 (step SD2), and the tag information “HW key”. And the acquired common key are stored in the RAM 204 in association with each other (step SD3).

  Since the tag information extracted in step SA2 is only the HW key, the PC 20A next performs the process of step SA9. Next, the PC 20A extracts the encrypted customer information 1C data and the tag information “HW key” added to the customer information 1C data. Then, the PC 20 reads the common key stored in the RAM 204 in association with the “HW key” and tries to decrypt the encrypted data of the customer information 1C using the read common key. Here, the common key stored in association with the “HW key” in the RAM 204 is the common key acquired from the HW key 60, that is, the common key used when encrypting the customer information 1C. The data of customer information 1C is decrypted, and an image of customer information 1C is generated (step SA9).

  Next, the PC 20A determines whether or not the decryption process has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “IC card + HW key” added to the encrypted employee information 1D is extracted. Next, similarly to the above-described operation, when there is an “IC card” in the extracted tag information, the PC 20A performs the process of step SA6 and associates the tag information “IC card” with the secret key and stores them in the RAM 204. Then, the tag information “HW key” and the acquired common key are associated with each other and stored in the RAM 204 by performing the process of step SA8.

  Next, the PC 20A extracts the encrypted employee information 1D data and the tag information “IC card + HW key” added to the employee information 1D data. The PC 20A reads the secret key stored in the RAM 204 in association with the “IC card” and the common key stored in the RAM 204 in association with the “HW key”, and uses the read secret key and common key. Attempts to decrypt the encrypted employee information 1D data. Here, the common key stored in association with the “HW key” in the RAM 204 is the common key acquired from the HW key 60, that is, the common key used when encrypting the employee information 1D. The secret key stored in association with the “IC card” in FIG. 4 decrypts the secret key that is paired with the public key used when encrypting the employee information 1D, that is, the data encrypted with the public key. Since it is a secret key that is sometimes used, the data of the employee information 1D is decrypted, and an image of the employee information 1D is generated.

  When the decryption processing of the encrypted data ends (step SA10; YES), the PC 20A extracts the non-encrypted non-confidential information 1E data from the document data, and generates an image represented by the extracted data ( Step SA11). Then, when the generation processing of the image represented by the document data is completed, the PC 20A displays the generated image on the display unit 207. As a result, the screen shown in FIG. 6 is displayed on the display unit 207. As a result, the manager A in the development department can decrypt all the encrypted data and display all the documents in the PC 20A as shown in FIG.

(Operation when general employee B in the development department displays a document on PC 20A)
Next, an operation when the general employee B in the development department displays a document on the PC 20A will be described. In the following description, the IC card 50B possessed by the general employee B is inserted into the IC card reader 212, and the HW key 60 is attached to the HW key IF 213. The operation from when the general employee B activates the word processor program on the PC 20A to when the tag information included in the document data is extracted is the same as the above-described operation. In this operation example, the operation when decrypting Table 1B and the operation when decrypting employee information 1D are different from the operation when manager A displays a document on PC 20A. Only the operation will be described.

  When the PC 20A extracts the tag information “IC card” in step SA2 (step SA5; YES), it determines whether an IC card is inserted in the IC card reader 212 (step SC1). Here, since the general employee B uses the PC 20A, the IC card 50B possessed by the general employee B is inserted into the IC card reader 212 (step SC1; YES). The PC 20A acquires the user identifier “A002” stored in the IC card 50B (step SC2), and transmits the acquired user identifier to the server device 30 (step SC3). When the transmitted user identifier is received by the server device 30, the server device 30 determines whether or not the received user identifier is stored. Here, since the server device 30 does not store the user identifier “A002”, the server device 30 transmits an error message to the PC 20A. When the PC 20A receives the error message (step SC4; NO), the PC 20A stores only the tag information “IC card” in the RAM 204 (step SC6).

  Next, the PC 20A attempts to decrypt the encrypted data in Table 1B. First, the PC 20A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the PC 20A cannot perform the decoding of Table 1B, and the image of Table 1B will not be generated (step SA9).

  Next, when the tag information “IC card + HW key” is extracted in the process of step SA2, the PC 20A performs the processes of step SA6 and step SA8 in the same manner as described above. Next, the PC 20A attempts to decrypt the encrypted employee information 1D data. First, the PC 20A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the PC 20A cannot decrypt the employee information 1D, and an image of the employee information 1D is not generated (step SA9).

  When the decryption processing of the encrypted data ends (step SA10; YES), the PC 20A extracts the non-encrypted non-confidential information 1E data from the document data, and generates an image represented by the extracted data ( Step SA11). Then, when the generation processing of the image represented by the document data is completed, the PC 20A displays the generated image. As a result, the screen shown in FIG. 12 is displayed. As a result, the general employee B in the development department cannot see the table 1B and the employee information 1D on the PC 20A as shown in FIG.

(Operation when the outsourced employee E in the development department displays a document on the PC 20A)
Next, the operation when the outsourced employee E in the development department displays a document on the PC 20A will be described. In the following description, the HW key 60 is attached to the HW key IF 213, but since the outsourced employee E does not have an IC card, it is not inserted into the IC card reader 212. In this operation example, the operation when decrypting Table 1B and the operation when decrypting employee information 1D are different from the operation when manager A displays a document on PC 20A. Only the operation will be described.

  When the tag information “IC card” is extracted in the process of step SA2 (step SA5; YES), the PC 20A determines whether or not an IC card is inserted in the IC card reader 212 (step SC1). Here, since the outsourced employee E does not have an IC card and no IC card is inserted in the IC card reader 212 (step SC1; NO), the user identifier cannot be obtained from the IC card, and the PC 20A Stores only the tag information “IC card” in the RAM 204 (step SC6).

  Next, the PC 20A attempts to decrypt the encrypted data in Table 1B. First, the PC 20A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the PC 20A cannot perform the decoding of Table 1B, and the image of Table 1B will not be generated (step SA9).

  Next, when the tag information “IC card + HW key” is extracted in the process of step SA2, the PC 20A performs the processes of step SA6 and step SA8 in the same manner as described above. Next, the PC 20A attempts to decrypt the encrypted employee information 1D data. First, the PC 20A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the PC 20A cannot decrypt the employee information 1D, and an image of the employee information 1D is not generated (step SA9).

  When the decryption processing of the encrypted data ends (step SA10; YES), the PC 20A extracts the non-encrypted non-confidential information 1E data from the document data, and generates an image represented by the extracted data ( Step SA11). Then, when the generation processing of the image represented by the document data is completed, the PC 20A displays the generated image. As a result, the screen shown in FIG. 13 is displayed. As a result, the outsourced employee E in the development department cannot see the table 1B and the employee information 1D on the PC 20A as shown in FIG.

(Operation when manager C in the sales department displays a document on PC 20B)
Next, an operation when the manager C in the sales department displays the document created by the manager A on the PC 20B will be described. Note that the operation from when the manager C starts the word processor program on the PC 20B to when the tag information included in the document data is extracted is the same as the above-described operation.

  In step SA2, the PC 20B first extracts the tag information “password” (step SA3: YES), and displays the window shown in FIG. 11 to prompt the user to input a password (step SB1). Since the employees belonging to the sales department do not know the password notified to the person belonging to the development department, after the screen shown in FIG. 11 is displayed, the common password “ABC” notified only to the person in the development department is displayed. "Cannot be entered. When the general employee D performs an operation of clicking the cancel button (step SB2; NO), the PC 20B stores only the tag information “password” in the RAM 204 (step SB4).

  Next, the PC 20B tries to decrypt the encrypted data of the graphic 1A. First, the PC 20B tries to read the password stored in the RAM 204 in association with the “password”. Here, as described above, the password “ABC” is not stored in the RAM 204 in association with the tag information “password”. For this reason, the PC 20B cannot acquire the common key for decrypting the graphic 1A, that is, the password “ABC”, cannot perform the decryption, and the image of the graphic 1A is not generated.

  Next, the PC 20A returns the process flow to step SA2 and extracts the tag information “IC card” (step SA5; YES), and determines whether or not an IC card is inserted in the IC card reader 212 (step SC1). ). Here, since the manager 20 is using the PC 20B, the IC card 50C possessed by the manager C is inserted into the IC card reader 212 (step SC1; YES). The PC 20B acquires the user identifier “B001” stored in the IC card 50C (step SC2), and transmits the acquired user identifier to the server device 30 (step SC3). When the transmitted user identifier is received by the server device 30, the server device 30 determines whether or not the received user identifier is stored. Here, since the server device 30 stores the user identifier “B001”, the server device 30 transmits the stored secret key to the PC 20B. When the transmitted secret key is received by communication unit 110 of PC 20B (step SC4; YES), PC 20B associates tag information “IC card” with the received secret key and stores them in RAM 204 (step SC5). ).

  Next, the PC 20B attempts to decrypt the encrypted data in Table 1B. First, the PC 20B reads the secret key stored in the RAM 204 in association with the “IC card”, and tries to decrypt the data in Table 1B encrypted with the public key, using the read secret key. Here, the secret key stored in the RAM 204 is a secret key that is paired with the public key used when encrypting Table 1B, that is, a secret key used when decrypting data encrypted with the public key. Therefore, the data in Table 1B is decoded, and the image in Table 1B is generated.

  Next, the PC 20B returns the process flow to step SA2 and extracts the tag information “HW key” (step SA7), and determines whether the HW key 60 is attached to the HW key IF 213 (step SD1). Here, since the PC 20B does not include the HW key IF 213 (step SD1; NO), the PC 20B cannot acquire the common key stored in the HW key 60, and stores only the tag information “HW key” in the RAM 204. (Step SD4).

  Next, the PC 20B tries to decrypt the encrypted data of the customer information 1C. Here, as described above, the RAM 204 stores no common key in association with the tag information “HW key”. For this reason, the PC 20B cannot decrypt the customer information 1C, and an image of the customer information 1C is not generated.

  Next, when the PC 20A returns the processing flow to step SA2 and extracts the tag information “IC card + HW key”, the processing of step SA6 and step SA8 is performed in the same manner as described above. Next, the PC 20A attempts to decrypt the encrypted employee information 1D data. First, the PC 20B tries to read the secret key stored in the RAM 204 in association with the “IC card” and the common key stored in the RAM 204 in association with the “HW key”. Here, as described above, the RAM 204 stores no common key in association with the tag information “HW key”. For this reason, the PC 20B cannot decrypt the employee information 1D, and an image of the employee information 1D is not generated.

  When the decryption processing of the encrypted data ends (step SA10; YES), the PC 20B extracts the non-encrypted non-confidential information 1E data from the document data, and generates an image represented by the extracted data ( Step SA11). Then, when the generation processing of the image represented by the document data is completed, the PC 20B displays the generated image. As a result, as shown in FIG. 14, the manager C cannot see the graphic 1A, the customer information 1C, and the employee information 1D on the PC 20B.

(Operation when general employee D in the sales department displays a document on PC 20B)
Next, an operation when the general employee D in the sales department displays a document on the PC 20B will be described. The operation from when the general employee B starts the word processor program on the PC 20B until the tag information included in the document data is extracted is the same as the above-described operation. In this operation example, the operation when decrypting Table 1B is different from the operation when the manager C displays a document on the PC 20B. Therefore, only the operation of this difference will be described below.

  Next, the PC 20B returns the process flow to step SA2 and extracts the tag information “IC card” (step SA5; YES), and determines whether an IC card is inserted in the IC card reader 212 (step SC1). ). Here, since the general employee D uses the PC 20B, the IC card 50D possessed by the general employee D is inserted into the IC card reader 212 (step SC1; YES). The PC 20B acquires the user identifier “B002” stored in the IC card 50D (step SC2), and transmits the acquired user identifier to the server device 30 (step SC3). When the transmitted user identifier is received by the server device 30, the server device 30 determines whether or not the received user identifier is stored. Here, since the server device 30 does not store the user identifier “B002”, the server device 30 transmits an error message to the PC 20B. When the error message is received in PC 20B (step SC4; NO), PC 20B stores only tag information “IC card” in RAM 204 (step SC6).

  Next, the PC 20B attempts to decrypt the encrypted data in Table 1B. First, the PC 20B tries to read the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the PC 20B cannot perform the decoding of Table 1B, and the image of Table 1B will not be generated.

  When the decryption processing of the encrypted data ends (step SA10; YES), the PC 20B extracts the non-encrypted non-confidential information 1E data from the document data, and generates an image represented by the extracted data ( Step SA11). Then, when the generation processing of the image represented by the document data is completed, the PC 20B displays the generated image. As a result, the screen shown in FIG. 15 is displayed. Thereby, as shown in FIG. 15, the general employee D cannot see the graphic 1A, the table 1B, the customer information 1C, and the employee information 1D on the PC 20B.

[Operation when outputting a document from the image forming apparatus]
Next, an operation when document data is transmitted from the PC to the image forming apparatus and a document is output from the image forming apparatus will be described.
(Operation when manager A instructs the image forming apparatus 10A to output a document)
When the manager A performs an operation of clicking the “file” item on the toolbar of the window while the document data is open on the PC 20A, a pull-down menu illustrated in FIG. 16 is displayed. Then, when the manager A performs an operation of clicking the “print” item in the pull-down menu, the window illustrated in FIG. 17 is displayed.

  Next, when the manager A performs an operation of clicking a check box of “accumulate documents in the image forming apparatus” in the menu shown in FIG. 17 and then an operation of clicking an “OK” button in the menu. The PC 20A transmits an accumulation instruction message for instructing to accumulate document data and document data including encrypted data to the image forming apparatus 10A. When the accumulation instruction message and the document data are received by the image forming apparatus 10 </ b> A, the image forming apparatus 10 </ b> A stores the received document data in the storage unit 105.

  Thereafter, the manager A inserts the IC card 50 </ b> A into the IC card reader 112 and attaches the HW key 60 to the HW key IF 113. Then, the image forming apparatus 10A is operated to input an output instruction for the stored document. When the image forming apparatus 10A is instructed to output the document data stored in the storage unit 105, the image forming apparatus 10A analyzes the document data and retrieves the tag information 3 from the data to be encrypted in the document data. It is determined whether there is any data (FIG. 18: step SA1). Here, since there is tag information 3 in the document data, YES is determined in step SA1.

  Next, the image forming apparatus 10A analyzes the document data and extracts tag information 3 in the document data (step SA2). Here, first, tag information “password” added to the encrypted data of the graphic 1A is extracted. Next, when the extracted tag information is “password” (step SA3; YES), the image forming apparatus 10A displays a screen for prompting the input of the password on the display unit 107 and prompts the input of the password (step SB1). Here, when the manager A inputs the common password “ABC” notified only to the person in charge of the development department and clicks the OK button (step SB2; YES), the image forming apparatus 10A performs the tagging. The information “password” and the input password “ABC” are associated with each other and stored in the RAM 104 (step SB3).

Since the tag information extracted in step SA2 is only the password, the image forming apparatus 10A decrypts the encrypted graphic 1A in the same manner as when the manager A displays the document on the PC 20A. Then, an image of the graphic 1A is generated (step SA9).
Next, the image forming apparatus 10A determines whether or not the decryption processing has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “IC card” added to the encrypted table 1B is extracted. Next, when the extracted tag information is “IC card” (step SA5: YES), the image forming apparatus 10A determines whether an IC card is inserted in the IC card reader 112 (step SC1). Here, since the IC card 50A is inserted in the IC card reader 112 (step SC1; YES), the user identifier “A001” stored in the IC card 50A is acquired (step SC2). Then, similarly to the PC 20A, the acquired user identifier is transmitted to the server device 30 (step SC3), the secret key transmitted from the server device 30 is received (step SC4; YES), and the tag information “IC card” is received. The associated secret key is stored in the RAM 104 in association with it (step SC5).

  Next, the image forming apparatus 10A performs the decryption of the encrypted table 1B and generates the image of the table 1B in the same manner as when the manager A displays the document on the PC 20A (step SA9). Next, the image forming apparatus 10A determines whether or not the decryption processing has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “HW key” added to the encrypted customer information 1C is extracted. Next, when the extracted tag information is “HW key” (step SA7; YES), the image forming apparatus 10A determines whether the HW key 60 is attached to the HW key IF 113 (step SD1). Here, since the HW key 60 is attached to the HW key IF 113 (step SD1; YES), the image forming apparatus 10A acquires the common key stored in the HW key 60 (step SD2), and the tag information “ The “HW key” and the acquired common key are associated with each other and stored in the RAM 104 (step SD3).

  Next, the image forming apparatus 10A decrypts the encrypted customer information 1C and generates an image of the customer information 1C in the same manner as when the manager A displays the document on the PC 20A (step SA9). .

  Next, the image forming apparatus 10A determines whether or not the decryption processing has been completed for all the encrypted data (step SA10). Here, since the decoding process has not been completed for all data, the process flow returns to step SA2 (step SA10; NO).

  Next, in step SA2, the tag information “IC card + HW key” added to the encrypted employee information 1D is extracted. Similarly to the above-described operation, when the extracted tag information includes an “IC card”, the image forming apparatus 10A performs the process of step SA6 and associates the tag information “IC card” with the secret key and stores them in the RAM 204. Then, the tag information “HW key” and the acquired common key are associated with each other and stored in the RAM 204 by performing the process of step SA8.

  Next, the image forming apparatus 10A extracts the encrypted employee information 1D data and the tag information “IC card + HW key” added to the employee information 1D data. Then, the image forming apparatus 10A reads out the secret key stored in the RAM 204 in association with the “IC card” and the common key stored in the RAM 204 in association with the “HW key”, and shares the read secret key. An attempt is made to decrypt the encrypted employee information 1D using the key. Here, the common key stored in association with the “HW key” in the RAM 204 is the common key acquired from the HW key 60, that is, the common key used when encrypting the employee information 1D. The secret key stored in association with the “IC card” in FIG. 4 decrypts the secret key that is paired with the public key used when encrypting the employee information 1D, that is, the data encrypted with the public key. Since it is a secret key used at times, the data of the employee information 1D is decrypted, and an image of the employee information 1D is generated (step SA9).

  When the decryption process of the encrypted data is completed (step SA10; YES), the image forming apparatus 10A generates an image of the non-confidential information 1E (step SA11). When the image forming apparatus 10 </ b> A generates an image of a document, the image forming apparatus 10 </ b> A transmits image data representing the generated image to the image processing unit 111. The image processing unit 111 performs image processing such as gradation correction and screen processing on the image represented by the image data, generates image data of each color of YMCK, and outputs the image data to the image forming unit 109. When image data is supplied from the image processing unit 111, the image forming unit 109 forms an image represented by the image data on a recording sheet, and discharges the recording sheet on which the image is formed to the outside of the image forming apparatus 10A. Thereby, manager A can obtain a recording sheet on which images of graphic 1A, table 1B, customer information 1C, employee information 1D, and non-confidential information 1E are formed.

(Operation when general employee B instructs the image forming apparatus 10A to output a document)
Next, an operation when the general employee B in the development department instructs the image forming apparatus 10A to output a document will be described. The operation from when the storage instruction message and the document data are transmitted from the PC 20A to the image forming apparatus 10A until the document data is stored in the image forming apparatus 10A is the same as the operation when the manager A instructs the output. . In this operation example, the operation when decrypting the table 1B and the operation when decrypting the employee information 1D are different from the operation when the manager A outputs a document from the image forming apparatus 10A. Only the operation of this difference will be described.

  The general employee B inserts the IC card 50B possessed by the general employee B into the IC card reader 112 and attaches the HW key 60 to the HW key IF 113. Then, the image forming apparatus 10A is operated to input an output instruction for the stored document.

  When the tag information “IC card” is extracted in the process of step SA2 (step SA5; YES), image forming apparatus 10A determines whether an IC card is inserted in IC card reader 112 (step SC1). Here, since the IC card 50B is inserted in the IC card reader 112 (step SC1; YES), the user identifier “A002” stored in the IC card 50B is acquired (step SC2). Then, similarly to the PC 20A, the acquired user identifier is transmitted to the server device 30 (step SC3). Here, since the user identifier “A002” is not stored in the server device 30, an error message is transmitted from the server device 30 (step SC4; NO), and the image forming apparatus 10A receives only the tag information “IC card”. Store in the RAM 104 (step SC6).

  Next, the image forming apparatus 10A attempts to decrypt the encrypted data in Table 1B. First, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the image forming apparatus 10A cannot perform the decoding of Table 1B, and the image of Table 1B is not generated (Step SA9).

  Next, when the tag information “IC card + HW key” is extracted in the process of step SA2, the image forming apparatus 10A performs the processes of step SA6 and step SA8 as in the above-described operation. Then, the image forming apparatus 10A attempts to decrypt the encrypted data of the employee information 1D. First, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 104 in association with the “IC card”. Here, as described above, the RAM 104 stores no secret key in association with the tag information “IC card”. For this reason, the image forming apparatus 10A cannot decrypt the employee information 1D, and an image of the employee information 1D is not generated (step SA9).

  When the decryption process of the encrypted data is completed (step SA10; YES), the image forming apparatus 10A generates an image of the non-confidential information 1E (step SA11). When the image forming apparatus 10A generates an image of the document, the image of the document is formed on the recording sheet according to the image data representing the generated image, and the recording sheet on which the image is formed is discharged out of the image forming apparatus 10A. Thereby, the general employee B can obtain a recording sheet on which images of the graphic 1A, the customer information 1C, and the non-confidential information 1E are formed.

(Operation when the outsourced employee E instructs the image forming apparatus 10A to output a document)
Next, the operation when the outsourced employee E in the development department instructs the image forming apparatus 10A to output a document will be described. The operation from when the storage instruction message and the document data are transmitted from the PC 20A to the image forming apparatus 10A until the document data is stored in the image forming apparatus 10A is the same as the operation when the manager A instructs the output. . In this example of operation, the operation when decrypting the table 1B and the operation when decrypting the employee information 1D are different from the operation when the manager A displays a document in the image forming apparatus 10, and therefore, Only the operation of this difference will be described.

  Since the outsourced employee E does not have an IC card and cannot insert the IC card into the IC card reader 112, only the HW key 60 is attached to the HW key IF 113. Then, the image forming apparatus 10A is operated to input an output instruction for the stored document.

  When the tag information “IC card” is extracted in the process of step SA2 (step SA5; YES), image forming apparatus 10A determines whether an IC card is inserted in IC card reader 112 (step SC1). Here, since no IC card is inserted in the IC card reader 112 (step SC1; NO), the image forming apparatus 10A stores only the tag information “IC card” in the RAM 104 (step SC6).

  Next, the image forming apparatus 10A attempts to decrypt the encrypted data in Table 1B. First, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the image forming apparatus 10A cannot perform the decoding of Table 1B, and the image of Table 1B is not generated (Step SA9).

  Next, when the tag information “IC card + HW key” is extracted in the process of step SA2, the image forming apparatus 10A performs the processes of step SA6 and step SA8 as in the above-described operation. Next, the image forming apparatus 10A attempts to decrypt the encrypted employee information 1D data. First, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 104 in association with the “IC card”. Here, as described above, the RAM 104 stores no secret key in association with the tag information “IC card”. For this reason, the image forming apparatus 10A cannot decrypt the employee information 1D, and an image of the employee information 1D is not generated (step SA9).

  When the decryption process of the encrypted data is completed (step SA10; YES), the image forming apparatus 10A generates an image of the non-confidential information 1E (step SA11). When the image forming apparatus 10A generates an image of the document, the image of the document is formed on the recording sheet according to the image data representing the generated image, and the recording sheet on which the image is formed is discharged out of the image forming apparatus 10A. Thereby, the outsourced employee E can obtain a recording sheet on which images of the graphic 1A, the customer information 1C, and the non-confidential information 1E are formed.

(Operation when manager C instructs the image forming apparatus 10A to output a document)
Next, an operation when the sales department manager C instructs the image forming apparatus 10A to output a document will be described. The operation from when the storage instruction message and the document data are transmitted from the PC 20B to the image forming apparatus 10A until the document data is stored in the image forming apparatus 10A is the same as the operation when the manager A instructs the output. .

  The manager C inserts the IC card 50C possessed by the manager C into the IC card reader 112. Since the HW key 60 is owned by a person in the development department, the HW key 60 is not attached to the HW key IF 113 here. Then, the image forming apparatus 10A is operated to input an output instruction for the stored document. When the image forming apparatus 10A is instructed to output the document data stored in the storage unit 105, the image forming apparatus 10A analyzes the document data and retrieves the tag information 3 from the data to be encrypted in the document data. It is determined whether there is any data (FIG. 18: step SA1). Here, since there is tag information 3 in the document data, YES is determined in step SA1.

  Next, the image forming apparatus 10A analyzes the document data and first extracts the tag information “password” added to the encrypted data of the graphic 1A (step SA3; YES). Displayed on the display unit 107 and prompts the user to enter a password (step SB1). Here, since the manager C does not know the common password “ABC” notified only to the person in the development department and cannot input the password (step SB2; NO), the image forming apparatus 10A Only the tag information “password” is stored in the RAM 104 (step SB4).

  Next, the image forming apparatus 10A attempts to decrypt the encrypted data of the graphic 1A. First, the image forming apparatus 10A attempts to read a password stored in the RAM 104 in association with the “password”. Here, as described above, the password “ABC” is not stored in the RAM 104 in association with the tag information “password”. For this reason, the image forming apparatus 10A cannot acquire the common key for decrypting the graphic 1A, that is, the password “ABC”, cannot perform the decryption, and the image of the graphic 1A is not generated. Become.

  Next, the image forming apparatus 10A returns the process flow to step SA2 and extracts the tag information “IC card” (step SA5: YES), and determines whether an IC card is inserted in the IC card reader 112. (Step SC1). Here, since the IC card 50C is inserted in the IC card reader 112 (step SC1; YES), the user identifier “B001” stored in the IC card 50C is acquired (step SC2). Then, similarly to the PC 20A, the acquired user identifier is transmitted to the server device 30 (step SC3), the secret key transmitted from the server device 30 is received (step SC4; YES), and the tag information “IC card” is received. The associated secret key is stored in the RAM 104 in association with it (step SC5).

  Next, the image forming apparatus 10A decrypts the encrypted table 1B and generates the image of table 1B in the same manner as when the manager C displays the document on the PC 20B (step SA9).

  Next, the image processing apparatus 10A returns the processing flow to step SA2 and extracts the tag information “HW key” (step SA7; YES), and determines whether or not the HW key 60 is attached to the HW key IF 113. (Step SD1). Here, since the HW key 60 is not attached to the image forming apparatus 10A (step SD1; NO), the image forming apparatus 10A cannot acquire the common key stored in the HW key 60, and the tag information “ Only the “HW key” is stored in the RAM 104 (step SD4).

  Next, the image forming apparatus 10A attempts to decrypt the encrypted data of the customer information 1C. Here, as described above, the RAM 104 does not store a common key in association with the tag information “HW key”. For this reason, the image forming apparatus 10A cannot decrypt the customer information 1C, and an image of the customer information 1C is not generated.

  Next, when the image forming apparatus 10A returns the process flow to step SA2 and extracts the tag information “IC card + HW key”, the process of step SA6 and step SA8 is performed in the same manner as described above. Then, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 104 in association with the “IC card” and the common key stored in the RAM 104 in association with the “HW key”. Here, as described above, the RAM 104 stores no common key in association with the tag information “HW key”. For this reason, the image forming apparatus 10A cannot decrypt the employee information 1D, and the image of the employee information 1D is not generated.

When the decryption process of the encrypted data is completed (step SA10; YES), the image forming apparatus 10A generates an image of the non-confidential information 1E (step SA11). When the image forming apparatus 10A generates an image of the document, the image of the document is formed on the recording sheet according to the image data representing the generated image, and the recording sheet on which the image is formed is discharged out of the image forming apparatus 10A.
As a result, the manager C can obtain a recording sheet on which images of the table 1B and the non-confidential information 1E are formed.

(Operation when general employee D instructs the image forming apparatus 10A to output a document)
Next, the operation when the general employee D in the sales department instructs the image forming apparatus 10A to output the document will be described. The operation from when the storage instruction message and the document data are transmitted from the PC 20B to the image forming apparatus 10A until the document data is stored in the image forming apparatus 10A is the same as the operation when the manager C instructs the output. Therefore, the description is omitted. In this operation example, the operation when decrypting the table 1B and the operation when decrypting the employee information 1D are different from the operation when the manager B outputs a document in the image forming apparatus 10A. Only the operation of this difference will be described.

  The general employee D inserts the IC card 50D possessed by the general employee D into the IC card reader 112. Since the HW key 60 is owned by a person in the development department, the HW key 60 is not attached to the HW key IF 113 here. Then, the image forming apparatus 10A is operated to input an output instruction for the stored document.

  When the tag information “IC card” is extracted in the process of step SA2 (step SA5; YES), image forming apparatus 10A determines whether an IC card is inserted in IC card reader 112 (step SC1). Here, since the IC card 50B is inserted in the IC card reader 112 (step SC1; YES), the user identifier “B002” stored in the IC card 50B is acquired (step SC2). Then, similarly to the PC 20B, the acquired user identifier is transmitted to the server device 30 (step SC3). Here, since the user identifier “B002” is not stored in the server device 30, an error message is transmitted from the server device 30 (step SC4; NO), and the image forming apparatus 10A receives only the tag information “IC card”. Store in the RAM 104 (step SC6).

  Next, the image forming apparatus 10A attempts to decrypt the encrypted data in Table 1B. First, the image forming apparatus 10A attempts to read out the secret key stored in the RAM 204 in association with the “IC card”. Here, as described above, the RAM 204 stores no secret key in association with the tag information “IC card”. For this reason, the image forming apparatus 10A cannot perform the decoding of Table 1B, and the image of Table 1B is not generated (Step SA9).

  Next, when the tag information “IC card + HW key” is extracted in the process of step SA2, the image forming apparatus 10A performs the processes of step SA6 and step SA8 as in the above-described operation. Then, the image forming apparatus 10A attempts to decrypt the encrypted data of the employee information 1D. First, the image forming apparatus 10A attempts to read out a secret key stored in the RAM 104 in association with the “IC card” and a common key stored in the RAM 104 in association with the “HW key”. Here, as described above, the RAM 104 stores no common key in association with the tag information “HW key”. For this reason, the image forming apparatus 10A cannot decrypt the employee information 1D, and the image of the employee information 1D is not generated.

  When the decryption process of the encrypted data is completed (step SA10; YES), the image forming apparatus 10A generates an image of the non-confidential information 1E (step SA11). When the image forming apparatus 10A generates an image of the document, the image of the document is formed on the recording sheet according to the image data representing the generated image, and the recording sheet on which the image is formed is discharged out of the image forming apparatus 10A. As a result, the general employee D can obtain a recording sheet on which only the non-confidential information 1E is formed.

[Operation in Other Image Forming Apparatus]
Next, an operation when document data is sent to another image forming apparatus will be described.
The image forming apparatus 10B does not include the HW key IF 113. For this reason, no one operates the image forming apparatus 10B, and no image is formed on the recording sheet for the customer information 1C.
Further, the image forming apparatus 10C does not include the IC card reader 112 and the HW key IF 113. Therefore, no matter which person operates the image forming apparatus 10B, no image is formed on the recording sheet for the table 1B, the customer information 1C, and the employee information 1D.
Further, the image forming apparatus 10 </ b> D does not have a communication function with the IC card reader 112, the HW key IF 113, and the server device 30. Therefore, no matter which person operates the image forming apparatus 10B, no image is formed on the recording sheet for the table 1B, the customer information 1C, and the employee information 1D.
For example, when the image forming apparatus 10D does not have a password input function, it is impossible to input a password. In the image forming apparatus 10D, only an image of non-confidential information is formed on a recording sheet. Become.

  As described above, according to this embodiment, a plurality of confidential information in a document can be encrypted by different means, and display and image formation can be controlled. Further, since the document is encrypted by a plurality of means, there is less possibility that the confidential part of the document is easily known. Further, the confidential part in the document is sent from the PC to the image forming apparatus in an encrypted state and stored. Since the stored document data is encrypted, even if the document data stored in the image forming apparatus is stolen, the confidential portion is not easily known.

[Modification]
As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment mentioned above, It can implement with another various form. For example, the present invention may be implemented by modifying the above-described embodiment as follows.

In the embodiment described above, an image is not generated when the document cannot be decrypted, but another image such as a black rectangle is generated and displayed instead of the image that could not be decrypted. Alternatively, an image may be formed.
In the embodiment described above, a watermark may be embedded in an image generated by decoding. In the image processing apparatus, the date and time when encrypted data was received, the date and time when it was decrypted, and the like may be stored in the storage unit 105 as a history.

  In the embodiment described above, a common key may be stored in the IC card, and the document may be encrypted / decrypted using this common key. Further, in this aspect, the server device 30 may not be connected to the communication network 40 and the secret key may not be transmitted from the server device 30.

  In the embodiment described above, the user identifier is input from the input unit 106 in the image forming apparatus, and the image forming apparatus transmits the input user identifier to the server apparatus 30 and receives the secret key from the server apparatus 30. The data may be decrypted.

  In the above-described embodiment, the IC card reader and the HW key IF may be freely attached / detached in each PC or image forming apparatus. According to this aspect, it is possible to restrict confidential information that can be browsed by each device.

It is the figure which illustrated the whole system configuration concerning an embodiment of the present invention. It is the figure which showed the hardware constitutions of PC20A and 20B. It is the figure which showed the information memorize | stored in IC card 50A-50D. 2 is a diagram illustrating a hardware configuration of an image forming apparatus 10A. FIG. It is the figure which showed the window displayed in PC. It is the figure which showed the window displayed in PC. It is the figure which illustrated the security policy of the document. It is the figure which showed the window displayed in PC. It is the figure which showed the window displayed in PC. It is the figure which showed the encrypted document typically. It is the figure which showed the window displayed in PC. It is the figure which showed the decrypted document. It is the figure which showed the decrypted document. It is the figure which showed the decrypted document. It is the figure which showed the decrypted document. It is the figure which showed the window displayed in PC. It is the figure which showed the window displayed in PC. 6 is a flowchart showing a flow of processing performed by the PC and the image forming apparatus. 6 is a flowchart showing a flow of processing performed by the PC and the image forming apparatus. 6 is a flowchart showing a flow of processing performed by the PC and the image forming apparatus. 6 is a flowchart showing a flow of processing performed by the PC and the image forming apparatus.

Explanation of symbols

10A to 10D: Image forming apparatus, 20A, 20B ... PC, 30 ... Server apparatus, 40 ... Communication network, 50A-50D ... IC card, 60 ... HW key, 101. ..Bus, 102 ... CPU, 103 ... ROM, 104 ... RAM, 105 ... Storage unit, 106 ... Input unit, 107 ... Display unit, 108 ... Image input unit 109 ... Image forming unit, 110 ... Communication unit, 111 ... Image processing unit, 112 ... IC card reader, 113 ... HW key IF, 201 ... Bus, 202 ... CPU, 203 ... ROM, 204 ... RAM, 205 ... storage unit, 206 ... input unit, 207 ... display unit, 210 ... communication unit, 212 ... IC card reader, 213 ... HW key IF

Claims (7)

A plurality of decryption key acquisition means each having different means for acquiring a decryption key for decrypting encrypted image information;
Extraction that extracts the tag information from the data in which the encrypted image information obtained by encrypting the image information with the encryption key and the tag information representing the decryption key acquisition means for decrypting the encrypted image information are associated with each other Means,
Acquisition means for representing a decryption key for decrypting encrypted image information associated with the tag information extracted by the extraction means, among the plurality of decryption key acquisition means, by the tag information extracted by the extraction means A decryption means for decrypting the encrypted image information using the obtained decryption key,
An image processing apparatus comprising: an image generation unit configured to generate an image represented by the image information according to the image information obtained by decoding by the decoding unit.   The image processing apparatus according to claim 1, further comprising a display unit that displays an image generated by the image generation unit.   The image processing apparatus according to claim 1, further comprising an image forming unit that forms an image generated by the image generating unit on a recording sheet.   The image processing apparatus according to claim 1, wherein the decryption key acquisition unit acquires the decryption key from an external apparatus. 2. The image generating unit generates a predetermined image instead of the image represented by the encrypted image information when the encrypted image information cannot be decrypted by the decrypting unit. An image processing apparatus according to 1. The data in which the encrypted image information obtained by encrypting the image information with the encryption key and the tag information representing the decryption key acquisition means for decrypting the encrypted image information are associated with the encrypted image information and the The image processing apparatus according to claim 1, wherein the image processing apparatus has a plurality of sets with tag information, and the means for obtaining a decryption key represented by each tag information is different for each set. A plurality of encryption key acquisition means each having different means for acquiring an encryption key for encrypting image information;
Display means for displaying an image;
An operation means having a plurality of operators;
An area designating unit for designating an area in the image displayed on the display unit in accordance with an instruction given to the operation unit of the operation unit;
A selection unit that selects one or a plurality of encryption key acquisition units from among the plurality of encryption key acquisition units according to an operation performed by the operation unit of the operation unit;
An encryption unit that acquires an encryption key by an encryption key acquisition unit selected by the selection unit, and encrypts an image in an area specified by the area specification unit by the acquired encryption key;
An image processing apparatus comprising: data generation means for generating data including tag information representing the encryption key acquisition means selected by the selection means and information encrypted by the encryption means.

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