JP2008003883A - Image forming device and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device and an image forming system capable of decreasing the probability of leakage of image data. <P>SOLUTION: The image forming device and the image forming system includes a password generation part 416 for generating a password, an encryption key generation part 417 for generating an encryption key based on a user ID and the password, an encryption part 418 for encrypting the image data based on the encryption key, a synthesis process part 419 for synthesizing the encrypted image data and the password and generating encryption data, an HDD 21 for storing the encryption data, a decryption key generation part 420 for acquiring the password from the encryption data and generating a decryption key based on the acquired password and the user ID, a decryption part 421 for acquiring the image data by decrypting the encryption data based on the decryption key and a printer part 31 for forming the image on a recording paper based on the image data acquired by the decryption part 421. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and an image forming system that encrypt image data.

  In recent years, leakage of confidential information has become a major problem in companies, governments, local governments, and the like, and a technique for preventing leakage of confidential documents is strongly desired. In addition, companies, governments, local governments, etc. are making progress in information technology (IT), and by sharing paper documents, information sharing and reduction of management costs are being promoted. On the other hand, in an image forming apparatus such as a copying machine, digitization advances and an image of an original is acquired as electronic data, and image data read from the original is transmitted to another image forming apparatus via a network, or an HDD ( Hard Disk Drive) and those that are stored in a storage medium such as a removable memory card are known. In addition, not only copying, but also multifunction devices having functions such as a scanner, a printer, and a facsimile have become widespread, and document digitization has been actively performed using such devices.

However, since the digitized information becomes easy to handle, there is an increased risk of confidential information leaking. Therefore, the encrypted confidential document data is encrypted, and when forming an image of the encrypted confidential document, a predetermined password is requested, and a decryption key is generated from the password to decrypt the confidential document data. Such an image forming apparatus is known (for example, see Patent Document 1).
JP 2005-295541 A

  However, in an image forming apparatus that encrypts confidential document data, for example, when an encryption key or password for decrypting encrypted confidential document data is transmitted to another image forming apparatus via a network, a communication path There is a risk that the encryption key and password may be leaked due to eavesdropping. And if such a password or encryption key is known to a third party, it becomes possible for the third party to decrypt the encrypted confidential document data, which may leak confidential information There was an inconvenience.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus and an image forming system that can reduce the risk of leakage of image data.

  An image forming apparatus according to the present invention includes an image data acquisition unit that acquires image data, an identification information reception unit that receives identification information for identifying a user, a password generation unit that generates a password, and the identification information reception unit An encryption key generation unit that generates an encryption key based on the identification information received by the password generation unit and the password generated by the password generation unit, and the encryption key generated by the encryption key generation unit, An encryption unit that encrypts the image data acquired by the image data acquisition unit, and the image data encrypted by the encryption unit and the password generated by the password generation unit are combined to generate encrypted data An image forming unit that forms an image on a recording sheet, and a storage unit that stores encrypted data generated by the combining unit When the image receiving instruction is received by the instruction receiving unit and the instruction receiving unit, the password is acquired from the encrypted data stored in the storage unit, and the acquired password and the identification Stored in the storage unit based on the decryption key generation unit that generates a decryption key based on the identification information received by the information reception unit, and the decryption key generated by the decryption key generation unit A decrypting unit that decrypts the encrypted data to obtain the image data; and an image forming unit that forms an image on a recording sheet based on the image data obtained by the decrypting unit.

  According to this configuration, the image data acquisition unit acquires image data, the identification information reception unit receives user identification information, and the password generation unit generates a password. Also, the encryption key generation unit generates an encryption key based on the identification information and the password. Then, based on the encryption key generated by the encryption key generation unit, the encryption unit generates the encrypted data by encrypting the image data acquired by the image data acquisition unit, and stores the encrypted data in the storage unit. The Further, when an image forming instruction for forming an image on recording paper is received by the instruction receiving unit, a password is acquired from the encrypted data by the decryption key generating unit, and the acquired password and identification information receiving unit is used. A decryption key is generated based on the received identification information. Then, based on the decryption key generated by the decryption key generation unit, the decryption unit decrypts the encrypted data stored in the storage unit to obtain image data, and the image forming unit acquires this image. An image is formed on the recording paper based on the data.

  In this case, since the decryption key for decrypting the encrypted data is used only inside the image forming apparatus and cannot be known outside the image forming apparatus, it is difficult to illegally decrypt the encrypted data. The possibility of image data leaking can be reduced.

  Moreover, it is preferable that the said password production | generation part changes the said newly produced | generated password for every predetermined period. According to this configuration, since the password used for generating the encryption key changes every predetermined period, the difficulty of decryption increases, and the encryption strength increases.

  The password generation unit may change the newly generated password every time image data is acquired by the image data acquisition unit. According to this configuration, since the password used for generating the encryption key changes every time the image data is acquired by the image data acquisition unit, the difficulty of decryption increases, and the encryption strength is increased.

  Further, when the image is formed by the image forming unit, a new password is generated by the password generating unit, and the new password and the identification information receiving unit are received by the encryption key generating unit. A new encryption key is generated based on the identification information, and the image data used for forming the image is re-encrypted based on the new encryption key by the encryption unit, and the composition processing unit An encrypted data update processing unit that generates new encrypted data based on the re-encrypted image data and the new password, and stores the new encrypted data in the storage unit; preferable.

  According to this configuration, when an image is formed by the image forming unit, a new password is generated by the password generating unit, and the new password and the identification information received by the identification information receiving unit are received by the encryption key generating unit. A new encryption key is generated based on the information, and the image data used for forming the image is encrypted again based on the new encryption key by the encryption unit, and encrypted again by the composition processing unit. New encrypted data is generated based on the image data and the new password, and the new encrypted data is stored by the storage unit. As a result, each time image formation is performed on the recording paper, the encrypted data is Since the data is encrypted again with a new encryption key, the difficulty of decrypting the encrypted data increases even if the encryption key is leaked. There confidential information is decoded is a risk of leakage is reduced.

  In addition, the storage unit can transmit and receive data to and from a terminal device connected via a network, and transmits the encrypted data to the terminal device via the network to transmit the encrypted data to the terminal device. The encrypted data may be stored, and the encrypted data may be acquired from the terminal device via the network.

  According to this configuration, since the encrypted data is transmitted to the terminal device via the network and the encrypted data is stored by the terminal device, the encrypted data is transmitted by the terminal device connected to the image forming apparatus via the network. As a result, the convenience can be improved.

  An image forming system according to the present invention includes the above-described image forming apparatus and a terminal device connected to the image forming apparatus via a network so as to be able to transmit and receive data. The terminal device is connected to the image forming apparatus. The terminal-side storage unit that stores the encrypted data transmitted via the network, the terminal-side reception unit that receives an image formation instruction to form an image on recording paper, and the image formation by the terminal-side reception unit A terminal control unit that transmits the image formation instruction and the encrypted data stored in the terminal-side storage unit to the image forming apparatus via a network when the instruction is accepted;

  According to this configuration, the encrypted data is transmitted to the terminal device via the network, and the encrypted data is stored in the terminal-side storage unit in the terminal device. When the terminal side accepting unit accepts the image forming instruction, the image forming instruction and the encrypted data stored in the terminal side storing unit are transmitted to the image forming apparatus via the network. In this case, the decryption key for decrypting the encrypted data is not transmitted / received between the image forming apparatus and the terminal device via the network, but is used only inside the image forming apparatus, and Since it cannot be known outside the apparatus, it is difficult to illegally decrypt the encrypted data, and the risk of leakage of the image data can be reduced.

  In the image forming apparatus and the image forming system configured as described above, the decryption key for decrypting the encrypted data is used only inside the image forming apparatus and cannot be known outside the image forming apparatus. The difficulty of illegally decoding the digitized data increases, and the risk of image data leaking can be reduced.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram showing an example of the configuration of an image forming system according to an embodiment of the present invention. An image forming system 1 shown in FIG. 1 includes an image forming apparatus 2 according to an embodiment of the present invention, a local area network (LAN) 3 and a public line 4 that are examples of a network, and terminal devices 5-1, 5-5. 2 and a printer 6. In the following description, the terminal devices 5-1 and 5-2 are denoted by reference numerals without suffixes when collectively referred to, and are denoted by reference numerals with suffixes when referring to individual configurations.

  The image forming apparatus 2 is connected to the terminal device 5-1 through the LAN 3. A public line 4 is connected to the LAN 3, and a printer 6 and a terminal device 5-2 are connected to the public line 4. The LAN 3 and the public line 4 allow the image forming apparatus 2, the printer 6, and the terminal devices 5-1 and 5-2 to exchange data with each other.

  The public line 4 is a network such as the Internet or a telephone line. The printer 6 is a so-called network printer configured to be accessible from the terminal device 5 via the LAN 3 or the public line 4. The printer 6 is an example of a general image forming apparatus different from the image forming apparatus according to the present invention.

  FIG. 2 is a block diagram showing an example of the configuration of the image forming apparatus 2 according to the embodiment of the present invention. An image forming apparatus 2 shown in FIG. 2 is a so-called multi-function machine having a plurality of functions relating to image formation such as a copying function, a printer function, a facsimile function, and a scanner function.

  The image forming apparatus 2 includes a scanner unit 11, an HDD 21 (storage unit), a memory card I / F 22 (storage unit), a printer unit 31 (image forming unit), a control unit 41, an operation panel unit 51 (identification information receiving unit, instruction). Reception unit), facsimile communication unit 61, network I / F unit 71 (identification information reception unit, instruction reception unit, storage unit), parallel I / F unit 72, and serial I / F unit 73. .

  Then, the scanned image data is encrypted by the scanner unit 11, HDD 21, control unit 41, operation panel unit 51, and network I / F unit 71 and sent as an e-mail to a pre-designated mail address or to an IP address. A network scanner function for direct transmission is realized. The scanner unit 11, HDD 21, printer unit 31, control unit 41, operation panel unit 51, and facsimile communication unit 61 realize a facsimile function. Further, the printer function is realized by the HDD 21, the printer unit 31, the control unit 41, the operation panel unit 51, the network I / F unit 71, and the parallel I / F unit 72. The scanner unit 11, the HDD 21, the printer unit 31, the control unit 41, and the operation panel unit 51 implement a copy function.

  The operation panel unit 51 is used for a user to perform operations related to a copy function, a printer function, a facsimile function, a scanner function, and the like, and forms an image for instructing an operation instruction by a user, for example, printing of information stored in the HDD 21. An instruction or the like is given to the control unit 41. In addition, the operation panel unit 51 has a password that is known only to a user who is permitted to access user identification information, for example, confidential information, that is, a user who knows the password is permitted to access confidential information. An input of a password that is identification information for identifying the user and a user ID that is identification information for individually identifying each user is accepted. The operation panel unit 51 includes a display unit 52 having a touch panel and the like, and an operation key unit 53 having a start key, a numeric keypad, and the like.

  The display unit 52 includes a touch panel unit that can display a combination of a touch panel and an LCD (Liquid Crystal Display), and displays various operation screens to enable input operations. For example, when the facsimile function is executed, the display unit 52 displays information about user selection, transmission destination selection, transmission setting, and the like, and operation buttons for the user to input various operation instructions by touching the part. Etc. are displayed. The operation key unit 53 is used for inputting various instructions such as a copy execution start instruction or a facsimile transmission start instruction by the user.

  The scanner unit 11 optically acquires a document image and generates image data. The scanner unit 11 includes an exposure lamp 12 and a CCD (charge coupled device) 13. The scanner unit 11 irradiates the document with the exposure lamp 12 and receives the reflected light by the CCD 13, thereby reading the document image and outputting image data corresponding to the read image to the control unit 41. The scanner unit 11 may be capable of reading not only a monochrome document but also a color document or a photo document.

  The HDD 21 corresponds to an example of a storage unit that stores document image data encrypted by the control unit 41, for example. The memory card I / F 22 is used to insert and contact various memory cards 23 such as a PCMCIA (Personal Computer Memory Card International Association) and a memory card compliant with a standard defined by SDA (SD Card Association). This is an interface circuit for storing data in the memory card 23 and reading data from the memory card 23. In this case, the memory card I / F 22 corresponds to an example of a storage unit that stores image data of an encrypted document in the memory card. Note that the storage medium is not limited to the memory card, and various storage media such as FD (Flexible Disk) and CD-R (Compact Disc-Recordable) can be used, and the storage medium is used instead of the memory card I / F 22. A corresponding interface circuit can be provided as a storage unit.

  The printer unit 31 receives original image data read by the scanner unit 11, image data received from an external personal computer or the like via the network I / F unit 71, and received from an external facsimile apparatus by the facsimile communication unit 61. Image data such as fax data is acquired from the control unit 41, and an image corresponding to the image data is printed on a predetermined recording sheet.

  The printer unit 31 includes, for example, a sheet conveying unit 32 having a sheet feeding cassette and a sheet feeding roller, an intermediate transfer member roller, a photosensitive drum, an image forming unit 33 having an exposure device and a developing device, a transfer unit having a transfer roller and the like. 34 and an electrophotographic image forming unit including a fixing unit 35 having a fixing roller and the like. Specifically, the paper transport unit 32 transports the recording paper to the image forming unit 33, the image forming unit 33 forms a toner image corresponding to the image data, and the transfer unit 34 transfers the toner image to the recording paper. The fixing unit 35 fixes the toner image on the recording paper to form an image.

  The printer unit 31 is not limited to an electrophotographic system that forms an image using toner. For example, an ink jet system that forms an image by ejecting ink onto a recording paper or an ink film that heats an ink film to form an image on the recording paper. Various systems such as a thermal transfer system for transfer can be used.

  The facsimile communication unit 61 includes an encoding / decoding unit (not shown), a modulation / demodulation unit (not shown), and an NCU (Network Control Unit) (not shown), and an image of a document read by the scanner unit 11. Data is transmitted to another facsimile apparatus via a communication line 611 such as a telephone line or an Internet line, and image data transmitted from another facsimile apparatus is received. The encoding / decoding unit compresses / decodes image data to be transmitted and expands / decodes received image data. The modem unit modulates the compressed / decoded image data into an audio signal. Or the received signal (audio signal) is demodulated into image data. The NCU controls connection with a facsimile machine as a transmission destination via a telephone line.

  The network I / F unit 71 uses a network interface (for example, 10 / 100base-TX) or the like to control transmission / reception of various data to / from the terminal device 5 connected via the LAN 3. For example, the network I / F unit 71 transmits the document image data read by the scanner unit 11 and encrypted by the control unit 41 to the terminal device 5 as an e-mail or prints it by the printer unit 31. 5 to receive the image data sent from 5.

  The parallel I / F unit 72 receives print data or the like from an external device by parallel transmission in which data is transmitted in units of a plurality of bits using a plurality of signal lines using a high-speed bidirectional parallel interface (for example, conforming to IEEE 1284) or the like. It is to be equal. The serial I / F unit 73 uses a serial interface (for example, RS-232C) or the like, and receives various data from an external device by serial transmission that sequentially transmits data bit by bit using a single signal line. To do.

  The control unit 41 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) that stores a predetermined control program, a RAM (Random Access Memory) that temporarily stores data, peripheral devices thereof, and the like. It has. As a result, the control unit 41 controls the entire image forming apparatus 2 in accordance with the instruction information received by the operation panel unit 51 and the like, and detection signals from sensors provided at various locations of the image forming apparatus 2. Do. More specifically, the control unit 41 executes a control program stored in the ROM, so that the scanner controller 412, the facsimile controller 413, the printer controller 414, the copy controller 415, the password generation unit 416, the encryption key generation Functions as a unit 417, an encryption unit 418, a composition processing unit 419, a decryption key generation unit 420, a decryption unit 421, and an encrypted data update processing unit 422. A program for realizing the above-described functions by being read by a computer as the control unit 41 is stored in a non-volatile and large-capacity external storage device such as the HDD 74 and is appropriately transferred to the main storage device such as the RAM. By doing so, it is also possible to provide execution by the CPU.

  The scanner controller 412 controls the operation of each unit used to realize the scanner function. The facsimile controller 413 controls the operation of each unit used to implement the facsimile function. When transmitting the facsimile, the facsimile controller 413 designates the telephone number stored in the HDD 21 via the communication line 611 for the image data of the original read by the scanner unit 11 by the facsimile communication unit 61. Send directly to a facsimile machine.

  The printer controller 414 controls the operation of each unit used for realizing the printer function. The copy controller 415 controls the operation of each unit used to implement the copy function.

  The password generation unit 416 generates a new password and outputs it to the encryption key generation unit 417 every time image data is read from the document by the scanner unit 11. For example, the password generation unit 416 cumulatively counts the current time information and date information obtained by using an unillustrated RTC (Real Time Clock), and the number of recording sheets on which image formation has been performed by the printer unit 31. A password is changed by generating a new password using information that changes at a certain frequency, such as a count value obtained by an approximate output number counter, periodically or irregularly. In this case, for example, when the password generation unit 416 generates a new password using date information, the newly generated password changes every day. Further, for example, when the password generation unit 416 generates a new password using the output number counter, the password changes whenever image formation is performed by the image forming apparatus 2, so that the image formation is substantially performed. The newly generated password changes every predetermined period according to the frequency of the passwords.

  Alternatively, the password generation unit 416 may use a random number generated using a known random number generation circuit or the like as the password. The password is for improving the encryption strength of the image data encrypted by the encryption unit 418, and it is sufficient if the password can be changed with a frequency that satisfies the required encryption strength. 416 does not necessarily have to generate a different password each time a password is generated.

  The encryption key generation unit 417 generates an encryption key based on the identification information received by the operation panel unit 51, for example, the user ID and the password generated by the password generation unit 416. For example, the password generation unit 416 performs multiplication, addition, and other various arithmetic processes using the user ID and the password to generate an encryption key.

  The encryption unit 418 encrypts the image data read by the scanner unit 11 using the encryption key generated by the encryption key generation unit 417 to generate encrypted data, and the HDD 21 and the memory card I / O The data is stored in the memory card 23 connected to F22. The encryption unit 418 can use various encryption methods such as DES (Data Encryption Standard) and AES (Advanced Encryption Standard) as the encryption method.

  When the image forming instruction and the user ID are received by the operation panel unit 51, the decryption key generation unit 420 uses the password from the encrypted data stored in the memory card 23 connected to the HDD 21 or the memory card I / F 22. And the decryption key is generated using the acquired password and the user ID received by the operation panel unit 51.

  The decryption unit 421 uses the decryption key generated by the decryption key generation unit 420 to decrypt the encrypted data stored in the HDD 21 or the memory card 23 connected to the memory card I / F 22. Image data is acquired and output to the printer unit 31 to perform an image forming operation.

  The terminal device 5 illustrated in FIG. 1 is configured using, for example, a personal computer, and includes, for example, a display device (not illustrated), a keyboard 501 (terminal side reception unit), an HDD 502 (terminal side storage unit), and a CPU. The control unit 503 (terminal side control unit) is provided. Then, the control unit 503 executes the control program stored in the HDD 502, thereby acquiring encrypted data stored in the HDD 21 in the image forming apparatus 2 via the LAN 3 or the public line 4 and storing it in the HDD 502. When the image forming instruction is received from the keyboard 501, the image forming instruction and the encrypted data stored in the HDD 502 are transmitted to the image forming apparatus 2 via the LAN 3 or the public line 4.

  Next, the operation of the image forming apparatus 2 configured as described above will be described. FIG. 3 is a flowchart showing an example of the operation of the image forming apparatus 2 when reading a document image. First, for example, the operation panel unit 51 is operated by a user, a user ID is received by the operation panel unit 51 (YES in step S1), and a document reading instruction for instructing reading of a document image is further received by the operation panel unit 51. If it is determined (YES in step S2), the image data of the document is read by the scanner unit 11 in accordance with a control signal from the scanner controller 412 and temporarily stored in, for example, the RAM provided in the control unit 41 (step S3). .

  Although an example in which image data is acquired by the scanner unit 11 is shown, the image data is acquired by communication processing of the facsimile communication unit 61, the network I / F unit 71, the parallel I / F unit 72, and the serial I / F unit 73. A configuration may be employed in which data is acquired. In this case, the scanner unit 11, the facsimile communication unit 61, the network I / F unit 71, the parallel I / F unit 72, and the serial I / F unit 73 correspond to an example of an image acquisition unit.

  Next, a password is generated by the password generation unit 416 (step S4). For example, the password generation unit 416 generates “060411” as the password from the date information “06/4/11” obtained by the RTC (not shown) (step S4). Next, the encryption key generation unit 417 adds the password “060411” to the user ID received by the operation panel unit 51, for example, “12345”, and generates the encryption key “12345060411” (step S5). .

  Next, the image data of the document temporarily stored in the RAM is encrypted by the encryption unit 418 using the encryption key “12345060411” (step S6). Then, the encrypted image data and the password “060411” are combined by the combining processing unit 419 and stored in the HDD 21 as the encrypted data D1 (step S7). FIG. 4 is an explanatory diagram showing an example of the data structure of the encrypted data D1. As shown in FIG. 4, the encrypted data D1 is synthesized, for example, by adding encrypted image data D3 after the password D2. The password D2 and the image data D3 may be combined as long as the password D2 can be extracted from the encrypted data D1, for example, the password D2 may be added after the image data D3. The password D2 may be embedded at a predetermined position of the data D3, or may be synthesized by various other methods.

  Further, the encrypted data D1 stored in the HDD 21 is transmitted to, for example, the terminal device 5-2 via the LAN 3 and the public line 4 by the network I / F unit 71 according to a control signal from the scanner controller 412, for example. In step S8, the data is stored in the HDD 502 in the terminal device 5-2, and the process is terminated.

  In this case, since the encryption key is not transmitted from the image forming apparatus 2 to the terminal apparatus 5-2, even if it is wiretapped by a third party on the communication path from the image forming apparatus 2 to the terminal apparatus 5-2. Therefore, the encryption key is not leaked, so that the possibility that the encrypted data D1 that has been wiretapped is decrypted and the confidential information is leaked is reduced.

  Next, an operation for causing the image forming apparatus 2 to form an image based on the encrypted data stored in the HDD 502 in the terminal apparatus 5-2 will be described. FIG. 5 is a flowchart illustrating an example of image forming processing based on encrypted data. First, for example, when the user operates the operation panel unit 51 to input a user ID, the user ID is received by the operation panel unit 51 (YES in step S10).

  Next, when an image formation instruction for causing the image forming apparatus 2 to perform image formation is received by the keyboard 501 of the terminal device 5-2 or a mouse (not shown), the control unit 503 The encrypted data D1 stored in the HDD 502 is transmitted to the image forming apparatus 2 via the public line 4 and the LAN 3. In the image forming apparatus 2, the network I / F unit 71 receives the image forming instruction and the encrypted data D1 transmitted from the terminal apparatus 5-2, and stores them in the HDD 21, for example (step S11). In this case, the network I / F unit 71 corresponds to an example of an instruction receiving unit.

  Note that the user ID may be input by operating the keyboard 501 of the terminal device 5-2 or a mouse (not shown). In this case, the user ID received by the keyboard 501 of the terminal device 5-2 or the mouse (not shown) is transmitted to the image forming apparatus 2 via the public line 4 and the LAN 3. The image forming apparatus 2 may receive the user ID transmitted from the terminal apparatus 5-2 by the network I / F unit 71. In this case, the network I / F unit 71 corresponds to an example of an identification information receiving unit, and the user ID received by the network I / F unit 71 instead of the user ID received by the operation panel unit 51 in the subsequent processing. Is used.

  Next, the decryption key generation unit 420 extracts and acquires the password D2, for example, “060411” from the encrypted data D1 stored in the HDD 21 (step S12). Then, the decryption key “42045” received by the operation panel unit 51 and the password “060411” are received from the decryption key generation unit 420 by the same decryption key “0” as the encryption key used for encrypting the image data D3. 12345060411 ”is generated (step S13).

  Next, the decryption unit 421 obtains the encrypted image data D3 from the encrypted data D1 stored in the HDD 21, and the image data D3 is decrypted using the decryption key “12345060411” (Step S1). S14). Then, according to the control signal from the printer controller 414, an image is formed on the recording paper based on the decoded image data (step S15).

  Then, when the identification information received by the operation panel unit 51 in step S1, for example, the user ID or password, matches the identification information received by the operation panel unit 51 in step S10, for example, the user ID or password, That is, when the user who has read the image data from the confidential document by the image forming apparatus 2 and the user who wants to form an image on the recording paper by the image forming apparatus 2 match, or access to the confidential information is permitted. The encryption key used for encrypting the image data and the decryption key used for decrypting the image data match only when the user who wants to form an image on the recording paper matches the confidentiality. Since the image data of the original can be correctly decrypted and an image obtained from the confidential original can be formed on the recording paper, A third party who does not know the third party different and passwords of over The ID is not able to form an image on a recording paper by using the encrypted data stored in the HDD 502.

  Next, the encrypted data update processing unit 422 updates the encrypted data using the new password D2 (step S16). Specifically, in response to the control signal from the encrypted data update processing unit 422, a new password is generated by the password generation unit 416 as in step S4, and the encryption key generation unit 417 performs the same as in step S5. A new encryption key is generated based on the new password and the user ID received by the operation panel unit 51, and the image is formed by the encryption unit 418 based on the new encryption key in the same manner as in step S6. The image data used for is encrypted again, and new encrypted data is generated based on the image data re-encrypted by the composition processing unit 419 and the new password in the same manner as in step S7, and updated in the HDD 21. Stored as encrypted data.

  Then, in response to a control signal from the encrypted data update processing unit 422, the updated encrypted data D1 stored in the HDD 21 is, for example, transmitted via the LAN 3 and the public line 4 by the network I / F unit 71. The data is transmitted to the terminal device 5-2 (step S17), stored in the HDD 502 in the terminal device 5-2, and the process ends.

  In this case, every time an image is formed on the recording paper based on the encrypted data D1, or every time an image is formed on the recording paper based on the encrypted data D1 after the encryption data D1 is encrypted and a certain period of time elapses. Since the encrypted data D1 is re-encrypted with a different encryption key, the difficulty of decrypting the encrypted data D1 increases even if the encryption key is leaked, and the encrypted data D1 is decrypted. The risk of leaking confidential information is reduced.

  Although the encrypted data D1 is stored in the terminal device 5 connected via the network, the encrypted data D1 is received from the terminal device 5 via the network, and decrypted. For example, the data D1 may be stored in the HDD 21, or may be stored in the memory card 23 connected to the memory card I / F 22, and the encrypted data D1 read from the HDD 21 or the memory card 23 may be decrypted.

  On the other hand, a case will be described in which image formation is performed based on the encrypted data stored in the HDD 502 of the terminal device 5-2 by the printer 6 that does not include the decryption key generation unit 420. For example, when a third party forms an image based on encrypted data stored in the HDD 502, that is, when an attempt is made to illegally acquire a secret, the encryption method used by the encryption unit 418 and the decryption unit 421, and the encryption key Can be obtained, the encrypted data is decrypted to obtain image data, and the printer 6 can form an image.

  However, in the image forming apparatus 2, the user inputs identification information such as a user ID and a password to the image forming apparatus 2, and the user directly inputs an encryption key and a decryption key to the image forming apparatus 2. The encryption key and the decryption key are not transmitted / received by communication. In addition, the encryption key and the decryption key are not included in the encrypted data D1, and are generated by the encryption key generation unit 417 and the decryption key generation unit 420, and the images such as the encryption unit 418 and the decryption unit 421 are generated. It is only used inside the forming apparatus 2 and cannot be known from the outside of the image forming apparatus 2. Therefore, even if a third party knows the encryption method used in the encryption unit 418 and the decryption unit 421, the encryption key and the decryption key cannot be known, so that the encrypted data can be decrypted. The difficulty increases, and the risk of leakage of image data acquired from the document can be reduced.

  Further, the password D2 for decrypting the image data D3 is changed at a certain frequency regularly or irregularly. As a result, the encryption strength of the image data D3 is increased, and as a result, there is a risk of secret leakage. Reduced.

1 is a block diagram illustrating an example of a configuration of an image forming system according to an embodiment of the present invention. 1 is a block diagram illustrating an example of a configuration of an image forming apparatus according to an embodiment of the present invention. 6 is a flowchart illustrating an example of an operation of the image forming apparatus when reading a document image. It is explanatory drawing which shows an example of the data structure of encryption data. It is a flowchart which shows an example of the image formation process based on encryption data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming system 2 Image forming apparatus 3 LAN
4 Public line 5 Terminal device 6 Printer 11 Scanner unit 21,502 HDD
22 Memory card I / F
23 memory card 31 printer unit 41 control unit 51 operation panel unit 61 facsimile communication unit 71 network I / F unit 412 scanner controller 413 facsimile controller 414 printer controller 415 copy controller 416 password generation unit 417 encryption key generation unit 418 encryption unit 419 Composition processing unit 420 Decryption key generation unit 421 Decryption unit 422 Encrypted data update processing unit 501 Keyboard 503 Control unit

Claims (6)

An image data acquisition unit for acquiring image data;
An identification information receiving unit that receives identification information for identifying a user;
A password generator for generating a password;
An encryption key generation unit that generates an encryption key based on the identification information received by the identification information reception unit and the password generated by the password generation unit;
An encryption unit that encrypts the image data acquired by the image data acquisition unit based on the encryption key generated by the encryption key generation unit;
A synthesis processing unit that generates encrypted data by synthesizing the image data encrypted by the encryption unit and the password generated by the password generation unit;
A storage unit for storing the encrypted data generated by the synthesis processing unit;
An instruction receiving unit for receiving an image forming instruction for forming an image on recording paper;
When the image forming instruction is received by the instruction receiving unit, the password is acquired from the encrypted data stored in the storage unit, and the acquired password and the identification received by the identification information receiving unit A decryption key generation unit that generates a decryption key based on the information;
A decryption unit that decrypts the encrypted data stored in the storage unit based on the decryption key generated by the decryption key generation unit, and acquires the image data;
An image forming apparatus comprising: an image forming unit that forms an image on a recording sheet based on the image data acquired by the decoding unit. The image forming apparatus according to claim 1, wherein the password generation unit changes the newly generated password every predetermined period. The image forming apparatus according to claim 1, wherein the password generation unit changes the newly generated password every time image data is acquired by the image data acquisition unit. When the image is formed by the image forming unit,
A new password is generated by the password generator,
Generating a new encryption key based on the new password and the identification information received by the identification information receiving unit by the encryption key generating unit;
Based on the new encryption key by the encryption unit, the image data used for forming the image is encrypted again,
Based on the image data re-encrypted by the synthesis processing unit and the new password, new encrypted data is generated,
The image forming apparatus according to claim 1, further comprising an encrypted data update processing unit that stores the new encrypted data in the storage unit. The storage unit is capable of transmitting and receiving data to and from a terminal device connected via a network, and transmits the encrypted data to the terminal device via the network, thereby transmitting the encrypted data to the terminal device. The image forming apparatus according to claim 1, wherein the encrypted data is acquired by receiving the encrypted data from the terminal device via the network. An image forming apparatus according to claim 5;
A terminal device connected to the image forming apparatus so as to be able to transmit and receive data via a network;
The terminal device
A terminal-side storage unit that stores the encrypted data transmitted from the image forming apparatus via the network;
A terminal-side receiving unit that receives an image forming instruction to form an image on recording paper;
When the image forming instruction is received by the terminal side receiving unit, a terminal control unit that transmits the image forming instruction and the encrypted data stored in the terminal side storage unit to the image forming apparatus via a network An image forming system comprising:

Images