JP2005311950A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus preventing leakage of secret information etc. without causing deterioration in performance and increase in the number of components. <P>SOLUTION: A compound machine 1 according to the present invention comprises: an encryption key producing unit 102 for producing each encryption key in every image forming job to be inputted; an encryption processing unit 17 for performing an encrypting process and a decoding process of the image forming job using the encryption key; an HDD 18 for nonvolatilely storing the image forming job which is encrypted; a SDRAM 19 for volatilely storing the encryption key; and an image forming part 14 for performing an image forming operation on the basis of the image forming job after being decoded. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, and more particularly to prevention of leakage of an image forming job including confidential information.

  2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine has an input image forming job (image data for one page or a plurality of pages and an image composed of predetermined processing instructions) in order to perform an image forming operation smoothly. In many cases, the image forming operation is performed based on an image forming job that is temporarily stored in a semiconductor memory (such as SDRAM [Synchronous Dynamic Random Access Memory]) and read sequentially from the semiconductor memory.

  On the other hand, some image forming jobs, such as a multi-sort sort print job, cannot start an image forming operation unless all job contents are prepared. However, the unit price of the semiconductor memory is expensive, and enormous costs are required to realize such an image forming job by increasing the capacity of the semiconductor memory.

Therefore, a general image forming apparatus includes a hard disk drive device having a low unit price in addition to a semiconductor memory as an auxiliary storage unit. The storage means temporarily stores the data.
JP 2001-188664 A JP 2002-73422 A

  Certainly, the image forming apparatus having the above-described configuration can cope with a large-capacity image forming job without causing an increase in the capacity of the semiconductor memory and an accompanying increase in cost.

  However, in the image forming apparatus having the above configuration, the hard disk drive device used as auxiliary storage means stores the written information in a nonvolatile manner, so that the power is shut off unless a predetermined erasing process is performed. Thereafter, the image forming job remained in the auxiliary storage unit. For this reason, the image forming apparatus having the above-described configuration has a problem that an image forming job (particularly, confidential information included in the auxiliary storage unit) easily leaks due to the stealing of the auxiliary storage unit. there were.

  Note that the simplest solution to the above problem is to overwrite the random number sequence or zero value immediately after the completion of the image forming process on the confidential information stored in the auxiliary storage unit. However, in such a solution, the data bus of the auxiliary storage unit is occupied during the overwriting process described above, and any data access to the auxiliary storage unit cannot be performed. There is a problem that the image forming apparatus cannot be advanced, and the performance of the image forming apparatus is deteriorated.

  Further, conventionally, print control is performed in which input print data is encrypted and stored without printing, and decryption and printing of the encrypted print data is performed only when an authentication process is performed by an intended user. An apparatus is disclosed and proposed (see, for example, Patent Document 1). However, the above prior art is merely intended to print the print data only in front of the intended user, and the print data is encrypted as a countermeasure against leakage of confidential information. Yes, but not so much about the confidentiality of the encryption key. Therefore, when the storage means for storing the encrypted print data and the storage means for storing the encryption key are stolen, there is a problem that it is no longer possible to prevent leakage of confidential information. .

  Further, conventionally, data to be stored is divided and stored in a plurality of memories as a piece of data that does not make sense by one, and when the memory is illegally removed, the data in other memories is erased. An information processing apparatus has been disclosed and proposed (see, for example, Patent Document 2). Certainly, the information processing apparatus having the above configuration can appropriately prevent leakage of stored data. However, in order to realize the above-described configuration, a plurality of memories are required, which may lead to an increase in cost and an increase in apparatus scale due to an increase in the number of parts.

  In view of the above problems, an object of the present invention is to provide an image forming apparatus capable of preventing leakage of confidential information or the like without causing a decrease in performance or an increase in the number of parts.

  In order to achieve the above object, an image forming apparatus according to the present invention includes an encryption key generating unit that generates an individual encryption key for each input image forming job, and the image forming job using the encryption key. Encryption means for encrypting, first storage means for storing the encrypted image forming job in a non-volatile manner, second storage means for storing the encryption key in a volatile manner, and encryption The apparatus includes a decryption unit that decrypts an image forming job using the encryption key, and an image forming unit that performs an image forming operation based on the decrypted image forming job. As described above, when the encryption key is stored in the volatile second storage means, when the power to the device is cut off or when the second storage means is removed from the device. The encryption key can be lost without requiring special erasure processing. Therefore, it is possible to reduce the risk of the encryption key being leaked and prevent leakage of confidential information and the like.

  In the image forming apparatus configured as described above, the encryption unit may be configured to generate the encryption key based on time information when the image forming job is input. In this way, by configuring the encryption key based on uncertain factors, it is possible to reduce the risk of the encryption key being located by a third party and prevent leakage of confidential information, etc. It becomes. In addition, when multiple image forming jobs are input, the encryption key corresponding to each image forming job will be different, so in the unlikely event that one encryption key is stolen by a third party. However, the risk of finding the other encryption key is low, and it becomes possible to appropriately prevent leakage of confidential information and the like.

  In the image forming apparatus having the above-described configuration, the first storage unit is an image formation job that cannot start an image forming operation unless all job contents are prepared, and the second storage unit Only an image forming job having a capacity that cannot be stored may be configured as auxiliary storage means for storing the image forming job. As described above, in principle, if the second storage unit is used as the development area of the image forming job and the image forming job is developed on the first storage unit only if it is unavoidable, the confidential information may be used. It is possible to suppress the occurrence of a situation in which an image forming job including the above is stored in a non-volatile manner, that is, an unfavorable security situation in which leakage of confidential information or the like is a concern.

  As described above, with the image forming apparatus according to the present invention, it is possible to prevent leakage of confidential information and the like without incurring a decrease in performance or an increase in the number of parts.

  In the following, a case where the present invention is applied to a network compatible digital multifunction peripheral having functions as a copying machine, a printer, a scanner, and a facsimile will be described as an example.

  FIG. 1 is a block diagram showing an embodiment of a digital multifunction peripheral according to the present invention. As shown in the figure, the digital multi-function peripheral 1 of the present embodiment includes a central processing unit 10 (hereinafter referred to as a CPU [Central Processing Unit] 10) that controls the operation of the entire apparatus, and a display that displays various information. Unit 11, an operation unit 12 (such as a numeric keypad or a touch panel) that accepts user operations, a document capture unit 13 that captures a document and generates image data, and an input image forming job (for one page or a plurality of pages) An image forming unit 14 (such as a printer head or a photosensitive drum) that forms an image on a sheet based on image data and an image forming request configured by a predetermined processing instruction), and an image obtained by the image forming unit 14 The information processing devices PC1 to PCn (personal computers) connected via a fixing unit 15 for fixing by heating and a network X (such as an in-house LAN [Local Area Network]). A communication unit 16 that communicates with a computer, an encryption processing unit 17 that performs encryption processing and decryption processing of an image formation job using an encryption key, which will be described later, and an encrypted image formation job. First storage means 18 (in this embodiment, a hard disk drive device is used as the first storage means 18, hereinafter referred to as HDD 18), and second encryption key is stored in a volatile manner. Storage means 19 (in the present embodiment, since SDRAM is used as the second storage means 19, hereinafter referred to as SDRAM 19).

  Although not shown in FIG. 1, the digital multi-function peripheral 1 naturally includes a paper storage unit, a paper transport unit, and the like necessary for the image forming operation in addition to the above-described components. The digital multifunction device 1 naturally includes a modem that converts image data into a facsimile signal, a network control unit that establishes a connection with a public telephone line, and the like as a configuration necessary for a facsimile transmission / reception operation.

  In the digital multi-functional peripheral 1 configured as described above, the CPU 10 functions as a timer unit 101 that detects the current time and an encryption key generation unit 102 that generates an individual encryption key for each input image forming job. In addition to controlling the operation of the entire apparatus, it also performs encryption key generation processing for an image forming job, which will be described in detail later. In order to facilitate the understanding of the description, the inside of the CPU is represented as an independent block in FIG. 1, but the processes in the units 101 and 102 are all executed by the CPU 10 in software.

  The communication unit 16 is a means for realizing an interface function with the information processing apparatuses PC1 to PCn serving as host devices outside the apparatus. As the communication unit 16, an Ethernet (registered trademark) standard network I / F card or the like is used. Can be used. If a single host device is connected, USB (Universal Serial Bus) or the like can be used as the communication unit 16. Note that the information processing apparatuses PC1 to PCn transmit image forming jobs to the digital multi-function peripheral 1 and receive image data scanned by the digital multi-function peripheral 1 via the communication unit 16.

  The encryption processing unit 17 encrypts the input image forming job based on the encryption key generated by the encryption key generating unit 102 or decrypts the original image forming job from the encrypted image forming job. It is means to do.

  The HDD 18 is an image forming job that cannot start an image forming operation unless all job contents are prepared, such as a multi-sort sort print job, and is limited to an image forming job having a capacity that cannot be stored in the SDRAM 19. Auxiliary storage means for performing the storage. The HDD 18 stores the image forming job encrypted by the encryption processing unit 17.

  The SDRAM 19 is a means for storing the encryption key in a volatile manner, as well as a control program work area and an image forming job (image data obtained by the document take-in unit 13 and printing input from the information processing apparatuses PC1 to PCn). It is also used as a temporary development area (including data etc.).

  As described above, in principle, the SDRAM 19 is used as the development area of the image forming job, and the image forming job including the confidential information is nonvolatile if the image forming job is developed on the HDD 18 only when it is unavoidable. Storage situation, that is, the occurrence of a situation unfavorable in terms of security where there is a risk of leakage of confidential information or the like can be suppressed.

  Next, the secret leakage prevention function of the digital multi-function peripheral 1 having the above-described configuration will be described in detail by taking as an example the case of performing multi-copy sort copy of multi-page documents.

  When a user operation for instructing multi-copy sort copy of a multi-page document is performed on the operation unit 12, the document capture unit 13 sequentially captures document information and starts conversion processing to image data. . Note that, in the above document fetching process, image data for multiple pages is generated, and thus the capacity of an image forming job including the image data tends to increase. Here, when the capacity of the image forming job is not large enough to be stored in the SDRAM 19, the image forming job is stored in the HDD 18 serving as auxiliary storage means.

  When the image forming job is stored in the HDD 18, the CPU 10 generates an encryption key used for encryption processing and decryption processing of the image forming job prior to the storage, and stores the generated encryption key in the SDRAM 19. To store. On the other hand, the encryption processing unit 17 reads the encryption key stored in the SDRAM 19, encrypts the image forming job, and stores it in the HDD 18.

  As described above, in the image forming process, if the input image forming job is once encrypted and then temporarily stored in the HDD 18, even if the HDD 18 is stolen by a third party, the encryption is not possible. Unless the digitizing key is stolen, it is possible to make it difficult to decipher the original image forming job. Accordingly, it is possible to prevent leakage of confidential information or the like without requiring an erasure process of the HDD 18 or the like.

  In particular, the encryption key generation unit 102 according to the present embodiment is configured to generate an encryption key based on the input time of the image forming job obtained by the timer unit 101. In this way, by configuring the encryption key based on uncertain factors, it is possible to reduce the risk of the encryption key being located by a third party and prevent leakage of confidential information, etc. It becomes.

  As described above, the digital multi-function peripheral 1 of the present embodiment is configured to separately store the encrypted image forming job and its encryption key in separate storage means. With such a configuration, it is possible to reduce the risk that the image forming job and its encryption key are stolen at the same time, and prevent leakage of confidential information and the like.

  Further, as described above, the digital multi-function peripheral 1 of the present embodiment is configured to store the encryption key in the volatile SDRAM 19. With this configuration, when the power to the device is cut off or when the SDRAM 19 is removed from the device, the encryption key can be lost without requiring special erasure processing. Therefore, it is possible to reduce the risk of the encryption key being leaked and prevent leakage of confidential information and the like.

  As described above, the SDRAM 19 of the present embodiment is used not only as an encryption key storage means but also as a work area for a control program and a temporary development area for an image forming job. Encryption keys that are no longer needed are sequentially overwritten and erased by subsequent device operations without requiring special erasure processing even when the device is not powered off. Therefore, it is possible to reduce the risk of the encryption key being leaked and prevent leakage of confidential information and the like.

  When the encrypted image forming job is stored in the HDD 18 for a predetermined number of pages, the encryption processing unit 17 reads out the encrypted image forming job and the corresponding encryption key from the HDD 18 and the SDRAM 19 to form the image. The data is transferred to the image forming unit 14 while decrypting the job encryption. The image forming unit 14 that has received the image forming job from the encryption processing unit 17 forms an image on a sheet based on the image forming job, and the fixing unit 15 performs the fixing process. A series of these processes is repeatedly executed until the desired number of copies designated by the user operation is reached, thereby realizing a multi-copy sort copy of a multi-page document.

  If another multi-copy sort copy is instructed during or after the above multi-copy sort copy process, the encryption key generation unit 102 performs encryption based on the input time of the image forming job as described above. A key is generated and stored in the SDRAM 19. That is, the encryption key corresponding to each image forming job is different. Therefore, even if one encryption key is stolen by a third party, the risk of finding the other encryption key is low and leakage of confidential information can be prevented appropriately. It becomes.

  The present invention is a useful technique for improving the security of image forming apparatuses in general, such as a copying machine, a printer, a facsimile machine, a facsimile machine, or a multifunction machine thereof.

These are the block diagrams which show one Embodiment of the digital multifunctional device which concerns on this invention.

Explanation of symbols

1 Digital MFP 10 Central processing unit (CPU)
DESCRIPTION OF SYMBOLS 101 Timer part 102 Encryption key generation part 11 Display part 12 Operation part 13 Document taking part 14 Image formation part 15 Fixing part 16 Communication part 17 Encryption processing part 18 1st memory | storage means (HDD etc.)
19 Second storage means (SDRAM etc.)
X network (in-house LAN, etc.)
PC1 to PCn Information processing device (personal computer, etc.)

Claims (3)

  An encryption key generating means for generating an individual encryption key for each input image forming job; an encrypting means for encrypting the image forming job using the encryption key; and an encrypted image forming job. First storage means for storing the information in a nonvolatile manner, second storage means for storing the encryption key in a volatile manner, and decryption means for decrypting the encrypted image forming job using the encryption key And an image forming means for performing an image forming operation based on the decoded image forming job.   The image forming apparatus according to claim 1, wherein the encryption unit generates the encryption key based on time information when the image forming job is input.   The first storage means is an image forming job that cannot start an image forming operation unless all job contents are prepared, and is limited to an image forming job having a capacity that cannot be stored in the second storage means. The image forming apparatus according to claim 1, wherein the image forming apparatus is an auxiliary storage unit that stores the data.

Images