JP2008066785A - Image processing system, and image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an image processor to generate an encryption key, which can be hardly extracted, in cooperation with an external device. <P>SOLUTION: The image processor generates a first encryption key when the setup of reliance on external devices is valid. The image processor confirms that a plurality of external devices having reliance relation are powered on, and requests first encryption keys from the respective external devices. Each external device transmits a first encryption key to the image processor. The image processor generates an encryption key from a plurality of first encryption keys from the external device and its own first encryption key. The image processor stops operating or limits execution of some of functions when an external device having reliance relation is powered off or when the reception of the first encryption key from the external device ends in failure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image processing system including an image processing apparatus that performs data encryption processing.

  In an image processing apparatus that performs processing such as copying, printing, facsimile, and data transmission, image data and management information are stored in a storage device, and image data and management information are transmitted to and received from an external device such as another image processing apparatus or server. I do. In order to prevent such data leakage, data encryption processing is performed. An encryption key for performing encryption is generated by the image processing apparatus. When outputting the encrypted data, the encryption key is also output.

  By the way, if the data stored in the apparatus is taken out and analyzed, the encryption key may be decrypted. Also, the encryption key may be decrypted when the output data is stolen by eavesdropping or the like. As a result, the data is decrypted and the data is leaked.

Therefore, for example, Patent Documents 1 and 2 describe that a plurality of encryption keys are generated, stored, and used for encryption processing. As a result, the encryption key obtained by encrypting the data cannot be easily decrypted.
JP 2005-318281 A JP-A-5-1115013

  As described above, even when a plurality of encryption keys are used, since the encryption key is stored in the apparatus, there is still a possibility that the encryption key is taken out and decrypted. Therefore, in view of the above, an object of the present invention is to provide an image processing system in which an encryption key cannot be generated by only one image processing apparatus and it is difficult to extract the encryption key.

  The present invention is an image processing system in which an image processing apparatus and an external apparatus are communicably connected and perform data encryption processing. The image processing apparatus includes generation means for generating an encryption key, and the generation means Uses an encryption information from an external device to generate an encryption key.

  The image processing apparatus alone does not generate an encryption key. By cooperating with the external device, the encryption information is acquired, and the encryption key is generated based on the encryption information. Therefore, an encryption key cannot be generated even if encryption information is extracted.

  The image processing apparatus includes setting means for setting a trust relationship with an external device, and acquires encryption information from the external device having the trust relationship. An encryption key is generated only with encryption information from an external device having a trust relationship. As a result, it is possible to prevent an encryption key from being illegally generated using an external device having no trust relationship.

  The generation unit of the image processing apparatus generates an encryption key based on the encryption information of the own apparatus and the encryption information acquired from the external apparatus. In order to generate the encryption key, a plurality of pieces of encryption information are required. Therefore, the external device includes a generating unit that generates a first encryption key, and the external device transmits the first encryption key as encryption information to the image processing device. The generation unit of the image processing apparatus generates a first encryption key as encryption information, and generates an encryption key based on the first encryption key and the first encryption key from the external apparatus.

  The external device generation unit generates an encryption key from the first encryption key generated by the own device and the first encryption key acquired from the image processing device and another external device, and the image processing device generates the encryption key. The encryption key and the encryption key generated by the external device are the same. In this way, a common encryption key can be generated by an image processing apparatus and an external apparatus having a trust relationship.

  Here, if even one of the image processing apparatus and the external apparatus is missing, the encryption information cannot be acquired and the encryption key is not generated. When the encryption information cannot be acquired from the external device in this way, the image processing device stops operating. Alternatively, some functions related to data processing are limited. Some functions to be limited may be functions related to security requiring encryption, for example, functions such as data transmission and filing. As a result, since the data itself does not exist, data leakage cannot occur.

  The image processing apparatus generates an encryption key when the power is turned on or restarted. That is, the encryption key is changed by turning off or restarting the power supply. For this reason, the same encryption key is not always used, and the risk of the encryption key being decrypted is reduced.

  According to the present invention, unless the image processing apparatus and the external apparatus having a trust relationship cooperate with each other, a plurality of pieces of encryption information necessary for generating the encryption key are not prepared. Therefore, even if the encryption information is extracted from one image processing apparatus, the encryption key cannot be generated, and it is difficult for the image processing system to extract the encryption key.

  An image processing system of this embodiment is shown in FIG. In this image processing system, a plurality of image processing apparatuses 1 and an information processing apparatus 2 such as a personal computer and a server are communicably connected through networks N1 to N4. The networks N1 to N4 are a LAN, a WAN, the Internet, and the like. The image processing device 1 and the information processing device 2 are connected to the individual networks N1 to N4, respectively. Network. Here, for any one image processing apparatus 1, the other image processing apparatus 1 and the information processing apparatus 2 are regarded as external apparatuses.

  The image processing apparatus 1 is a multifunction machine that executes a copy mode, a print mode, a scanner mode, and a facsimile mode. The image processing apparatus communicates with an operation unit 5 for performing display and input operations, an image reading unit 6 for reading an original and inputting image data, an image forming unit 7 for printing image data, and an external device. A communication unit 8, a modem unit 9 for facsimile communication, an image memory 10 for temporarily storing image data, a storage unit 11 for storing image data, and a management unit 12 for storing and managing various information. And a control unit 13 that controls the entire apparatus.

  As shown in FIG. 2, the operation unit 5 includes various operation keys 15 and a display unit 16, which are provided on the operation panel. The display unit 16 includes a liquid crystal display and is a touch panel. Touch keys are formed in the operation screen displayed on the display unit 16, and these are also referred to as operation keys 15.

  The image reading unit 6 includes a scanner device that reads an image of a document and inputs it as image data, and an automatic document transport device that automatically transports the document. That is, the image reading unit 6 executes a data input function for inputting image data.

  The communication unit 8 is a communication interface for communicating with an external device through a network. The communication unit 8 inputs and outputs image data with an external device. The modem unit 9 is connected to the public telephone line network Nn and performs facsimile communication with the facsimile apparatus 17 which is an external apparatus. The modem unit 9 is capable of data communication with an external device such as a server or a portable information terminal by dial-up connection. That is, the communication unit 8 and the modem unit 9 execute a data input function for inputting image data and a data transmission function for transmitting and outputting image data.

  The image forming unit 7 includes a photoconductor, a charging device, a laser beam exposure device, a transfer device, a cleaning device, and a fixing device, and forms an image on a sheet by an electrophotographic method. The image forming unit 7 performs color printing, but may perform only monochrome printing. The image formation is not limited to the electrophotographic method, but may be another method such as an ink jet method or a thermal transfer method. As described above, the image forming unit 7 executes a data output function for printing and outputting image data.

  The image memory 10 is composed of, for example, a DRAM. The image memory 10 temporarily stores input image data or output image data such as read image data, image data received from an external device, image data to be output by printing or data communication. The image data is subjected to image processing such as compression, decompression, and processing by an image data processing unit. The image data subjected to the image processing is stored in the storage unit 11.

  The storage unit 11 includes a hard disk device. The storage unit 11 accumulates the image data transferred from the image memory 10. At this time, the image data may be encrypted. The storage unit 11 also stores log information created when each function is executed. Then, image data is read from the storage unit 11 according to a user instruction or an external device instruction, and the image data is output to the outside by printing, data transmission, or facsimile communication. In other words, the storage unit 11 executes a filing function for saving input image data for output.

  Note that the output image data is erased from the storage unit 11 in accordance with an instruction from the control unit 13. At the time of this erasure, the image data is invalidated so that it cannot be restored by overwriting the image data with random data.

  The management unit 12 includes a non-volatile memory, and stores information necessary for operating the image processing apparatus 1 such as control information, setting information, and user authentication information of the image processing apparatus 1. When these pieces of information are created and changed, the management unit 12 updates the information as needed.

  The control unit 13 includes a CPU, reads a control program stored in the ROM 18 into the RAM, and executes the control program. As each unit operates according to the control program, the data input function, data output function, data transmission function, and filing function are executed. The control program also includes a browser and mail software, and the control unit 13 performs data communication with an external device or transmits / receives an e-mail using a communication protocol such as a TCP / IP protocol.

  Here, the image processing apparatus 1 encrypts the image data with the encryption key when executing the data transmission function or the filing function. In order to generate an encryption key, the image processing apparatus 1 includes a setting unit 20 that sets a trust relationship with the external device, and a generation unit that generates an encryption key using encryption information from the external device having the trust relationship. 21 and an acquisition unit 22 that acquires encryption information from an external device, and these are controlled by the control unit 13. Similarly, the external device includes a setting unit 20, a generation unit 21, and an acquisition unit 22.

  The setting unit 20 determines an external device that establishes a trust relationship by an input operation from the operation unit 5. That is, the trust setting is performed by the user performing the following operation. The user setting key on the operation panel shown in FIG. 2 is operated, and the user setting screen shown in FIG. 3 is displayed. When the key operator program key is operated, a screen for authenticating the user is displayed. When the user enters the service code, a program setting screen is displayed.

  Here, when the security setting key is operated, a security setting screen shown in FIG. 4 is displayed. When the trust setting key is operated, a list of external devices connected to the network is displayed. The user selects an external device that the user wants to establish a trust relationship with. As a result, the trust setting is validated, and an external device that establishes a trust relationship is determined. A list of external devices having a trust relationship in this way is stored in the management unit 12 as trust setting information. Here, the image processing device 1 is set to have a trust relationship with the first to third external devices. If there is no external device having a trust relationship, the trust setting is invalid.

  In the external apparatus with which the image processing apparatus 1 has a trust relationship, the trust relationship with the image processing apparatus 1 is set. When the image processing apparatus 1 transmits the trust setting information to the external apparatus, the external apparatus automatically performs the trust setting. It should be noted that the user may operate and set in the external device. Therefore, the image processing apparatus 1 and the external apparatus have a mutual trust relationship.

  The acquisition unit 22 operates the communication unit 8 to communicate with the external device and receive encryption information from the external device. The external devices that are communication partners are a plurality of external devices that have a trust relationship. The encryption information is a first encryption key that the external device has. The generation unit 21 of the external device generates a first encryption key. The generation unit 21 generates a first encryption key and stores it in the management unit 12 or the storage unit 11 when the power of the external device is turned on or restarted. Similarly, when the image processing apparatus 1 is turned on or restarted, the generation unit 21 generates a first encryption key and stores the first encryption key in the management unit 12 or the storage unit 11. .

  Then, the generation unit 21 generates an encryption key using the first encryption key acquired from each external device and the first encryption key generated by the own device. That is, an encryption key is generated according to a predetermined algorithm by combining a plurality of first encryption keys. The generated encryption key is stored in the RAM.

  Here, the length of the first encryption key is, for example, 64 bits. The encryption key generated based on this is, for example, 128 bits or 256 bits, and is longer than the first encryption key. Thus, by synthesizing a plurality of first encryption keys to generate an encryption key, an encryption key with high encryption strength can be completed.

  Next, a procedure when the image processing apparatus 1 generates an encryption key will be described with reference to FIG. First, the control unit 13 of the image processing apparatus 1 checks whether the trust setting is valid. When the trust setting is invalid, the image processing apparatus 1 generates an encryption key alone. Data is encrypted with this encryption key, and a predetermined function such as data transmission is executed.

  When the trust setting is valid, the image processing apparatus 1 generates its own first encryption key. Thereafter, the control unit 13 confirms the operating state of the external device. That is, the control unit 13 transmits a confirmation signal to all external devices by multicast. If the power supply of the external device is on, the external device is in an energized state and returns a response signal.

  If the power of the external device is off, the external device is not energized and no response signal is returned. At this time, the image processing apparatus 1 repeats transmission of the confirmation signal a plurality of times.

  Thereby, the control unit 13 determines the operating state of the external device. Note that the confirmation signal may be transmitted only to the external device having the trust relationship, without transmitting the confirmation signal to all the external devices.

  When the image processing apparatus 1 confirms that all the external apparatuses are in the operating state, it requests the external apparatus to transmit the first encryption key. The external device subject to this request is an external device having a trust relationship. Upon receiving this request, the external device transmits the first encryption key to the image processing device 1.

  The image processing apparatus 1 receives the first encryption key from the requested external apparatus. The control unit 13 confirms whether or not all the first encryption keys of the external devices having the trust relationship have been received. When all the first encryption keys are received, the control unit 13 generates an encryption key from all the first encryption keys received from the external device and its own first encryption key.

  The image processing apparatus 1 encrypts data using a generated encryption key according to a predetermined algorithm such as AES (Advanced Encryption Standard) or RSA (Rivest Shamir Adleman). When the filing function is executed, the encrypted data is stored in the storage unit 11. When the data transmission function is executed, the image processing apparatus 1 transmits the encrypted data to the external device. The external device stores the received data in the storage unit.

  When the operation involving encryption ends, the control unit 13 of the image processing apparatus 1 stores the generated encryption key in the RAM. Alternatively, the encryption key may be erased, and the encryption key can be prevented from being taken out illegally.

  The timing for generating the encryption key is when the image processing apparatus 1 or the external apparatus is turned on or restarted. In this case, the encryption key is stored in the RAM, and the encryption key is automatically deleted when the power is turned off or restarted. In addition, an encryption key may be generated when a predetermined function is executed. In this case, when the function ends, the control unit 13 deletes the encryption key.

  On the other hand, when the external apparatus having the trust relationship is not in the operating state or when the external apparatus has not transmitted the first encryption key, the control unit 13 of the image processing apparatus 1 performs control for limiting its own operation. In addition, the fact is notified by a display or the like. That is, the operation of the image processing apparatus 1 is stopped so that no function is executed. Alternatively, security related functions are restricted. For example, execution of the filing function is prohibited or execution of the data transmission function is prohibited. Other functions can be performed.

  Here, when the encryption method is a common key encryption method, the generated encryption key is a common key. When the encryption key is generated in the same manner in the external apparatus, this encryption key is the same as the encryption key generated in the image processing apparatus 1. In this case, the image processing apparatus 1 or the external apparatus that has received the data from the image processing apparatus 1 can decrypt the data with the generated encryption key.

  When the encryption method is a public key encryption method, the image processing apparatus 1 generates two different encryption keys by the above procedure. Then, the image processing apparatus 1 transmits one encryption key as a public key to the external apparatus, and stores and manages the other encryption key as a secret key. When the external device transmits the data encrypted with the public key to the image processing device 1, the image processing device 1 can decrypt the data with the secret key.

  Conversely, the image processing apparatus 1 transmits one encryption key as a secret key to the external apparatus and stores the other encryption key as a public key. When the image processing apparatus 1 transmits the data encrypted with the public key to the external apparatus, the external apparatus can decrypt the data with the secret key.

  As described above, in order to generate an encryption key used for data encryption processing, a plurality of first encryption keys are required, and it is necessary to cooperate with a plurality of external devices having a trust relationship. At this time, the image processing apparatus 1 and the external apparatus only manage the first encryption key. Even if the first encryption key is taken out illegally, it is difficult to decrypt the real encryption key. Therefore, even if data leaks, it cannot be decrypted, and the security of the image processing system can be improved.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention. As the encryption information necessary for generating the encryption key, unique information possessed by the image processing apparatus or the external apparatus may be used. Examples of unique information include a MAC address, an IP address, and a model number.

The figure which shows schematic structure of the image processing system and image processing apparatus of this invention The figure which shows the operation panel of an image processing apparatus Diagram showing the operation screen when setting trust The figure which shows the operation screen which sets the external device which ties the trust relationship Flowchart for generating encryption key

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing device 5 Operation part 6 Image reading part 7 Image formation part 8 Communication part 9 Modem part 11 Storage part 12 Management part 13 Control part 20 Setting part 21 Generation part 22 Acquisition part

Claims (12)

An image processing system in which an image processing apparatus and an external apparatus are communicably connected and perform data encryption processing. The image processing apparatus includes generation means for generating an encryption key, and the generation means is an external apparatus. An image processing system for generating an encryption key using encryption information from The image processing system according to claim 1, wherein the image processing apparatus includes setting means for setting a trust relationship with the external device, and obtains encryption information from the external device having the trust relationship. The image processing system according to claim 1, wherein the generation unit of the image processing apparatus generates an encryption key based on the encryption information of the own apparatus and the encryption information acquired from the external apparatus. The external device includes a generating unit that generates a first encryption key, and the external device transmits the first encryption key as encryption information to the image processing device. Image processing system. The generation unit of the image processing apparatus generates a first encryption key as encryption information, and generates an encryption key by using the first encryption key and the first encryption key from the external apparatus. The image processing system according to claim 4. The external device generation unit generates an encryption key from the first encryption key generated by the own device and the first encryption key acquired from the image processing device and another external device, and the image processing device generates the encryption key. 6. The image processing system according to claim 5, wherein the encryption key and the encryption key generated by the external device are the same. The image processing system according to claim 1, wherein the image processing apparatus generates an encryption key when the power is turned on or restarted. The image processing system according to claim 1, wherein the image processing apparatus stops the operation when the encryption information cannot be acquired from the external apparatus. The image processing system according to claim 1, wherein the image processing apparatus restricts some functions related to data processing when encryption information cannot be acquired from an external apparatus. An image processing apparatus that is communicable with an external device and performs data encryption processing, and includes a generation unit that generates an encryption key. The generation unit encrypts data using encryption information acquired from the external device. An image processing apparatus for generating an encryption key. The image processing apparatus according to claim 10, further comprising a setting unit that sets a trust relationship with the external device, wherein the generation unit acquires encryption information from the external device having the trust relationship. The generating means generates a first encryption key as encryption information, and generates the encryption key by using the first encryption key and the first encryption key that is the encryption information acquired from the external device. The image processing apparatus according to claim 10 or 11.

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