JP2005080099A - Image forming device, image processing method therefor and image forming system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve security in a system in which an image forming device is used as a scanner. <P>SOLUTION: An image forming device 2A includes an encryption key generation processor 11 for generating a paired secret key having a public key A and a secret key B. Image data acquired by a scanner 5 are encrypted by an encryption processor 13 using the public key A, and then stored in a storage 8. The secret key B is transmitted to a terminal 3A. The image data stored in the storage 8 are fetched by the terminal 3A, and decrypted by a decryption processor 22 in the terminal 3A using the secret key B transmitted from the image forming device 2A. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus, an image forming system, and an image processing method for the image forming apparatus.

  Conventionally, image forming apparatuses have been used for the purpose of copying images, but recent digital multi-function peripherals use a function that can store images as electronic data in a storage medium such as a memory or a hard disk (HDD). The image is read by the original reading device, the image data is stored in the storage medium of the main body, the user takes out the image data from the image forming device to his / her personal computer (PC) via the network, and the read image data is sent by e-mail. A scanner function for transmitting to a PC is realized. The function of extracting image data from the image forming apparatus by the PC is called PULL scan, and the function of transmitting image data from the image forming apparatus to the PC by e-mail or the like is called PUSH scan.

  Also, a function as a document server is realized in which the HDD of the image forming apparatus is used as a data storage server, and documents and documents are stored in the HDD, and the user can retrieve and view them when necessary.

  On the other hand, when a document is stored in the main body as image data, or when a user sends image data from the image forming apparatus to his / her PC by e-mail or the like, highly confidential data resides in the storage medium of the main body In many cases, communication is performed via a network, and there is a security problem when handling important documents.

  For this reason, in order to protect security, access restrictions to documents using passwords are often used as a conventional technique. When a third party tries to access a confidential document, the user is prompted to enter the password, and the password If the password does not match the password registered in advance, a control that does not permit image data extraction or printing is often used (see, for example, Patent Document 1).

JP-A-10-276335

  However, in the case of password protection as described above, if a password is known to a third party, or if a password is leaked to a third party from a user operation log when entering the password, the third party However, there is a problem that image data can be taken out from the image forming apparatus and used.

  SUMMARY An advantage of some aspects of the invention is that an image forming apparatus, an image forming system, and an image forming apparatus that make it impossible for a third party to use image data acquired by the image forming apparatus. An object is to provide a processing method.

  In order to solve the above-described problem, an image forming apparatus according to the present invention includes a reading unit that reads an image, and encrypts image data in an image forming apparatus connected to a network to which at least one terminal is connected. Encryption key generating means for generating a pair of encryption keys to be decrypted, encryption means for encrypting image data with an encryption key used for encryption generated by the encryption key generating means, and image data encrypted by the encrypting means And a communication unit for transmitting the encryption key used for the decryption generated by the encryption key generation unit to the terminal and transmitting the encrypted image data to the terminal.

  According to the image forming apparatus of the present invention, the encryption key generating unit generates a pair of encryption keys for encrypting and decrypting the image data, and the communication unit transmits the encryption key used for the decryption to the terminal. The encryption means encrypts the image data as an electrical signal obtained by reading the image by the reading means with the encryption key used for encryption generated by the encryption key generation means. The encrypted image data is stored in the storage means. The communication means transmits the encrypted image data to the terminal that has transmitted the encryption key used for decryption. Thereby, the terminal can decrypt the encrypted image data.

  An image forming system according to the present invention is an image forming system in which an image forming apparatus having a reading unit for reading an image and at least one terminal are connected via a network. An encryption unit that encrypts image data using a key, a storage unit that stores image data encrypted by the encryption unit, and a communication unit that transmits the image data encrypted by the encryption unit to the terminal The terminal includes an encryption key generating unit that generates a pair of encryption keys for encrypting and decrypting the image data, a communication unit that transmits an encryption key used for encryption generated by the encryption key generating unit to the image forming apparatus, And decryption means for decrypting encrypted image data received from the image forming apparatus with an encryption key used for decryption generated by the encryption key generation means.

  According to the image forming system of the present invention, the terminal generates a pair of encryption keys for encrypting and decrypting the image data by the encryption key generating unit, and transmits the encryption key used for encryption to the image forming apparatus by the communication unit. To do. In the image forming apparatus, the image data as an electric signal obtained by reading the image by the reading means is encrypted by the encryption means using the encryption key transmitted from the terminal, and the encrypted image data is stored by the storage means. .

  In response to a request from the terminal, the image forming apparatus transmits the encrypted image data stored in the storage unit to the corresponding terminal through the communication unit. The terminal decrypts the image data transmitted from the image forming apparatus by the decryption unit using the encryption key generated by the encryption key generation unit.

  An image processing method of an image forming apparatus according to the present invention uses an encryption key specified by a user in an image processing method of an image forming apparatus that reads an image and transmits image data as an electrical signal to a terminal via a network. Thus, the image data is encrypted, and the encrypted image data is transmitted to the terminal.

  According to the image processing method of the image forming apparatus according to the present invention, the image data is encrypted using the encryption key designated by the user, and the encrypted image data is transmitted to the terminal.

  In the image forming apparatus according to the present invention, when an image is read, an encryption key is generated, and the image data is encrypted and stored using the encryption key, so that a third party can extract and use the image data. Can be prevented. Also, since the encryption key for decryption is transmitted to the terminal and the encryption key for decryption is not left in the image forming apparatus itself, the image forming apparatus cannot decrypt the encrypted image data.

  In the image forming system according to the present invention, when an image is read by the image forming apparatus, an encryption key is generated at the terminal, the encryption key used for encryption is transmitted to the image forming apparatus, and the image forming apparatus uses the encryption key. Since the image data is encrypted and stored, it is possible to prevent a third party from taking out and using the image data from the image forming apparatus. Also, since the encryption key for decryption is used at the terminal and is not transmitted to the image forming apparatus, the image forming apparatus cannot decrypt the encrypted image data.

  In the image processing method of the image forming apparatus according to the present invention, the image data is encrypted using the encryption key designated by the user, and the encrypted image data is transmitted to the terminal. Data can be prevented from being extracted and used.

  As described above, in the image forming apparatus, the image forming system, and the image processing method of the image forming apparatus according to the present invention, the image data is encrypted with the encryption key for each user, so that a third party extracts the image data from the image forming apparatus. It cannot be used. In addition, since image data can be decrypted only by a terminal having an encryption key for decryption, image data acquired by the image forming apparatus can be used only by a specific user.

  Embodiments of an image forming apparatus, an image forming system, and an image processing method of the image forming apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration example of an image forming system according to the first embodiment. In the image forming system 1A according to the first embodiment, when the image forming apparatus 2A and the terminal 3A are connected via the network 4 and the image forming apparatus 2A reads image data, the image forming apparatus 2A encrypts the image data. A pair of encryption keys necessary for decryption is generated, and image data is encrypted using one encryption key in the image forming apparatus 2A. The other encryption key is sent to the terminal 3A, and when the image data read by the image forming apparatus 2A is used, the terminal 3A uses the other encryption key to decrypt the image data, thereby This makes it impossible for a person to use image data. The network 4 is a local area network (LAN), the Internet, or a combination of both, and is connected to at least one image forming apparatus 2A and at least one terminal 3A.

  First, the configuration of the image forming apparatus 2A according to the present embodiment will be described. The image forming apparatus 2A is a digital multifunction machine having a copy function, a printer function, a scanner function, and the like. And a storage unit 8, a communication I / F 9, a control unit 10A, and the like.

  The scanner unit 5 is an example of a reading unit, reads an image on a document, and outputs image data as an electrical signal. The printer unit 6 prints image data on paper. The operation unit 7 includes a liquid crystal display, a touch panel, a mechanical keyboard, and the like, and receives an operation of the user and displays an operation screen for guiding the operation to the user. The storage unit 8 is an example of a storage unit, and stores image data read by the scanner unit 5, a program executed by the control unit 10A, and the like.

  In the image forming system 1A according to the first embodiment, main functions executed by the control unit 10A of the image forming apparatus 2A will be described. The encryption key generation processing unit 11 is an example of an encryption key generation unit, and generates a pair of encryption keys composed of a public key A and a secret key B. The encryption key storage unit 12 stores the encryption key generated by the encryption key generation processing unit 11. Of the encryption keys stored in the encryption key storage unit 12, the public key A is sent to the encryption processing unit 13, and the secret key B is sent to the communication processing unit 14.

  The encryption processing unit 13 is an example of an encryption unit, and encrypts image data read by the scanner unit 5 with the public key A stored in the encryption key storage unit 12. The image data encrypted by the encryption processing unit 13 is stored in the image data storage area 8a of the storage unit 8. The communication processing unit 14 is an example of a communication unit, and transmits the secret key B stored in the encryption key storage unit 12 to the network 4 via the communication I / F 9 using a predetermined protocol. Further, the image data stored in the image data storage area 8a of the storage unit 8 is transmitted to the network 4 via the communication I / F using a predetermined protocol.

  Next, the configuration of the terminal 3A will be described. The terminal 3A is a personal computer (PC), for example, and includes a display unit 15, an input unit 16, a storage unit 17, a communication I / F 18, a control unit 19A, and the like. The display unit 15 is composed of a liquid crystal display, for example, and displays image data and the like. The input unit 16 includes a keyboard, a mouse, and the like, and receives user operations. The storage unit 17 stores image data acquired from the image forming apparatus 2A, a program executed by the control unit 19A, and the like.

  In the image forming system 1A according to the first embodiment, main functions executed by the control unit 19A of the terminal 3A will be described. The communication processing unit 20 receives the secret key B transmitted from the image forming apparatus 2 </ b> A to the network 4 via the communication I / F 18. Also, the image data transmitted from the image forming apparatus 2A to the network 4 is received via the communication I / F 18.

  The secret key B received by the communication processing unit 20 is stored in the encryption key storage unit 21, and the image data received by the communication processing unit 20 is stored in the storage unit 17. The decryption processing unit 22 decrypts the encrypted image data stored in the storage unit 17 with the secret key B stored in the encryption key storage unit 21. The image data decoded by the decoding processing unit 22 is displayed on the display unit 15, for example. Alternatively, it is stored in the storage unit 17.

  Next, the mechanism of the image forming apparatus 2A will be described. FIG. 2 is an internal configuration diagram illustrating an example of the image forming apparatus 2A, and illustrates a monochrome digital multi-function peripheral. The image forming apparatus 2 </ b> A includes an apparatus main body 31 and an automatic document feeder 32. First, the configuration of the apparatus main body 31 will be described. The apparatus main body 31 includes a scanner unit 5, a printer unit 6, a paper feed unit 33, a fixing unit 34, a paper discharge unit 35, a reversing unit 36, and a conveyance unit 37.

  The scanner unit 5 includes an original glass 38, a slit glass 39, an image sensor 40, a lamp 41, and a mirror group 42 that guides reflected light from the lamp 41 to the image sensor 40.

  The original glass 38 is a rectangular glass having a predetermined size on which the original P1 can be placed, and the slit glass 39 is an elongated glass extending in the main scanning direction. The lamp 41 and the mirror group 42 are moved in the sub-scanning direction by a driving mechanism (not shown). Thus, the entire surface of the document P1 placed on the document glass 38 can be irradiated with light, and the reflected light can be read by the image sensor 40. Further, by positioning the lamp 41 and the mirror group 42 on the lower surface of the slit glass 39, the document P 1 conveyed by the automatic document feeder 32 can be irradiated with light, and the reflected light can be read by the image sensor 40. .

  The paper feed unit 33 includes a plurality of paper feed cassettes 43 for storing paper P2 of different sizes, and a transport mechanism 44 such as a roller that feeds and transports the paper P2 from each paper feed cassette 43, and has a predetermined size. The paper P2 is supplied to the printer unit 6. The printer unit 6 includes a corona charger 45, a photosensitive drum 46, an exposure unit 47, a developing unit 48, a transfer charger 49, a separation charger 50, a cleaning unit 51, and the like.

  The corona charger 45 charges the photosensitive drum 46 to a predetermined voltage prior to the latent image forming process. The photosensitive drum 46 is obtained by applying a photosensitive layer to the surface of a cylindrical base material, and is rotationally driven by a driving mechanism (not shown). After the photosensitive drum 46 is rotated and uniformly charged by the corona charger 45, exposure by the exposure unit 47 is performed, and an electrostatic latent image is formed on the surface of the photosensitive drum 46.

  The exposure unit 47 reflects a beam emitted from a laser (not shown) by a polygon mirror and irradiates the surface of the photosensitive drum 46. The polygon mirror rotates at a constant rotation speed, and the main scanning of the laser beam is performed by the rotation of the polygon mirror. Further, the laser beam is sub-scanned by the rotation of the photosensitive drum 46. Thereby, an electrostatic latent image is formed on the surface of the photosensitive drum 46. The electrostatic latent image formed on the photosensitive drum 46 is visualized by the developing unit 48.

  The developing unit 48 includes a mechanism for stirring and supplying the toner stored in the developing sleeve 48 a and the like. The developing sleeve 48 a supplies the toner to the photosensitive drum 46 and attaches the toner to the electrostatic latent image on the photosensitive drum 46. Thus, a toner image is formed. The toner image on the photosensitive drum 46 is transferred from the photosensitive drum 46 to the paper P2 by the transfer charger 49, and the paper P2 on which the toner image has been transferred is separated from the photosensitive drum 46 by the separation charger 50 and is transferred to the fixing unit 34. Sent. That is, the transfer charger 49 is disposed opposite to the photosensitive drum 46, and discharges electric charge from the back side of the paper P2 superimposed on the photosensitive drum 46 electrostatically carrying the toner image, whereby the toner image is applied to the paper P2. Transcript. The separation charger 50 neutralizes the paper P2 attracted to the photosensitive drum 46 and separates the paper P2 from the photosensitive drum 46.

  The toner remaining on the surface of the photosensitive drum 46 without being transferred to the paper P2 is collected by the cleaning unit 51. The cleaning unit 51 includes a blade or the like that comes into contact with the photosensitive drum 46, and scrapes and stores the toner or the like adhering to the surface of the photosensitive drum 46. The fixing unit 34 includes a fixing device 52. As described above, the paper P2 onto which the toner image has been transferred by the printer unit 6 is sent to the fixing device 52, and the fixing device 52 applies pressure and heat to the paper P2 to fix the toner on the paper.

  The paper discharge unit 35 discharges the paper P2 processed by the fixing unit 34 to the outside. The reversing unit 36 includes a reversing conveyance path 53 and the like. By sending the paper P2 processed by the fixing unit 34 to the reverse conveyance path 53, the paper P2 is reversed and sent to the printer unit 6. The transport direction of the paper P2 that has passed through the fixing unit 34 is switched by the transport switching gate 54, and the paper P2 is sent to the paper discharge unit 35 or the reversing unit 36 depending on the operation mode. The transport unit 37 includes a transport path including the transport mechanism 44 and the reverse transport path 53 described above, and transports the paper P2.

  Next, the configuration of the automatic document feeder 32 will be described. The automatic document feeder (ADF) 32 includes a document tray 55, a paper discharge tray 56, a reverse tray 57, and a paper feed mechanism 58. The paper feed mechanism 58 includes a roller group such as a feed roller 59 that faces the slit glass 39 and a paper feed roller 60 that feeds the original P1 from the original tray 55 one by one.

  Next, the flow of the document P1 when reading an image from the document P1 will be described. A plurality of documents P1 set on the document tray 55 of the automatic document feeder 32 are fed out one by one by a paper feed roller 60 of a paper feed mechanism 58 and conveyed on the slit glass 39 by a feed roller 59. The original P 1 conveyed on the slit glass 39 is irradiated with light by the lamp 41, and the reflected light is read by the image sensor 40. When the document P1 is conveyed, the entire image can be read.

  If the original P1 that has passed through the slit glass 39 is read on only one side, it is discharged to the discharge tray 56. When reading both sides, the original P1 is sent to the reverse tray 57 and sent to the feed roller 59 again. As a result, the original P1 is turned upside down and sent onto the slit glass 39, and both the front and back sides of the original P1 can be read. The original P1 can also be read by placing one original P1 on the original glass 38.

  The image data read by the image sensor 40 can be printed on the paper P2 by the cooperation of the printer unit 6, the paper feed unit 33, the fixing unit 34, and the like. Further, it can be stored in the storage unit 8 shown in FIG. 1 without printing on the paper P2. In the present embodiment, when the image data is stored in the storage unit 8, it is encrypted and stored.

  In the image forming system 1A of the present embodiment, an asymmetric encryption method is used for encryption and decryption of image data. The asymmetric encryption method is an encryption method in which a key used for encryption and a key used for decryption are different, and an outline of an encryption method called RSA will be described as an example of an asymmetric encryption method.

First, e, d, and n are determined as follows.
p and q are prime numbers.
e is an integer of 3 to n-1, and the least common multiple of p-1 and q-1 and e are relatively prime.
d is a positive integer, and the product of e and d is congruent with 1 modulo the least common multiple of p-1 and q-1.
n is the product of p and q.

Plain text is 0? When expressed as an integer of n-1, that is, a block cipher in which the bit length when n is expressed as a binary number is a block cipher, encryption and encoding are performed using the following equations (1) and ( 2).
Ciphertext = remainder of dividing plaintext e to the power of n (1)
Decrypted text = remainder of dividing the dth power of ciphertext by n (2)
From the above formulas (1) and (2), the set of e and n is considered to be an encryption key, and the set of d and n is considered to be a decryption key.

  It is generally known that it is difficult to obtain a decryption key based on an encryption key, that is, to calculate d based on e and n. In order to calculate d based on e and n, it is necessary to factorize n and obtain p and q. However, since no mathematical method for efficiently performing factorization has been found, n has hundreds of digits. When it comes to the number of digits, factoring is impossible with current technology.

  Thereby, even if the encryption key is made public, the ciphertext cannot be decrypted using this key, and only the person having the decryption key can decrypt the ciphertext. The encryption key is called a public key, and the decryption key is called a secret key.

  FIG. 3 is a flowchart showing an operation example of the image forming system 1A according to the first embodiment, and the operation of the image forming system 1A according to the first embodiment using the asymmetric encryption method will be described below.

  First, the user operates the operation unit 7 of the image forming apparatus 2A shown in FIG. 1 to register a user ID as identification information, and a data storage area protected by the user ID in the image data storage area 8a of the storage unit 8 Is secured (step SA1). When the user scans an image to be kept secret, the user operates the operation unit 7 to instruct encrypted scanning (step SA2).

  Upon receiving the encryption scan instruction, the control unit 10A of the image forming apparatus 2A generates the public key A and the secret key B by the encryption key generation processing unit 11 (step SA3). The control unit 10A transmits the secret key B among the encryption keys generated by the encryption key generation processing unit 11 to the e-mail address of the user terminal 3A registered in advance by the communication processing unit 14 (step SA4). The secret key B is processed so as not to remain in the image forming apparatus 2A. Also, the control unit 10A temporarily stores the public key A in association with the user ID in the encryption key storage unit 12 (step SA5).

  When the communication processing unit 20 receives the secret key B, the control unit 19A of the terminal 3A used by the user stores it in the encryption key storage unit 21 (step SA6).

  The user operates the operation unit 7 of the image forming apparatus 2A to input a user ID, sets a document on the document tray 55 of the automatic document feeder 32 shown in FIG. 2, for example, and issues a scan start instruction ( Steps SA7 and SA8).

  Upon receiving an instruction to start scanning, the control unit 10A of the image forming apparatus 2A transports the document P1 set on the document tray 55, reads an image by the image sensor 40, and receives image data as an electrical signal from the scanner unit 5. Output (step SA9). The control unit 10A encrypts the image data output from the scanner unit 5 with the encryption processing unit 13 using the public key A stored in the encryption key storage unit 12 (step SA10). The control unit 10A stores the encrypted image data in the image data storage area 8a of the storage unit 8 in association with the user ID (step SA11).

  As described above, in the asymmetric encryption method, image data encrypted using the public key A cannot be decrypted using the public key A. Therefore, the image forming apparatus 2 </ b> A cannot decrypt the encrypted image data stored in the storage unit 8.

  When using the image data stored in the image forming apparatus 2A, the user operates the input unit 16 of the terminal 3A, inputs a user ID, and issues an image data acquisition instruction (step SA12). Note that image data is extracted by a procedure such as FTP (File Transfer Protocol). Upon receiving an image data acquisition request from the terminal 3A, the control unit 10A of the image forming apparatus 2A reads out the image data specified by the user ID from the image data storage area 8a of the storage unit 8, and the communication processing unit 14 uses the terminal. Transmit to 3A (step SA13).

  When the communication processing unit 20 receives the image data, the control unit 19A of the terminal 3A decrypts the encrypted image data by the decryption processing unit 22 using the secret key B stored in the encryption key storage unit 21. (Step SA14). The control unit 19A displays and outputs the decoded image data, for example, on the display unit 15 (step SA15).

  As described above, in the asymmetric encryption method, the image data encrypted using the public key A can be decrypted only using the secret key B. Therefore, the image data can be decrypted and used for display or the like only at the terminal 3A of the specific user holding the secret key B.

  Next, a second embodiment of the image forming system will be described. FIG. 4 is a block diagram illustrating a configuration example of an image forming system according to the second embodiment. In the image forming system 1B according to the second embodiment, an encryption key used in the image forming apparatus 2B is generated by the terminal 3B.

  First, the configuration of the image forming apparatus 2B will be described. The image forming apparatus 2B is a digital multi-function peripheral having a copy function, a printer function, a scanner function, and the like. The scanner unit 5, the printer unit 6, the operation unit 7, the storage unit 8, and the like. A communication I / F 9 and a control unit 10B are provided.

  The scanner unit 5 is an example of a reading unit, reads an image on a document, and outputs image data as an electrical signal. The printer unit 6 prints image data on paper. The operation unit 7 includes a liquid crystal display, a touch panel, a mechanical keyboard, and the like, and receives an operation of the user and displays an operation screen that guides the operation to the user. The storage unit 8 is an example of a storage unit, and stores image data read by the scanner unit 5, a program executed by the control unit 10B, and the like.

  In the image forming system 1B according to the second embodiment, main functions executed by the control unit 10B of the image forming apparatus 2B will be described. The encryption key storage unit 23 stores a public key A generated by the terminal 3B as will be described later. The encryption processing unit 24 is an example of an encryption unit, and encrypts image data read by the scanner unit 5 with the public key A stored in the encryption key storage unit 23. The image data encrypted by the encryption processing unit 24 is stored in the image data storage area 8a of the storage unit 8. The communication processing unit 25 is an example of a communication unit, and receives the public key A transmitted from the terminal 3B. Further, the image data stored in the image data storage area 8a of the storage unit 8 is transmitted to the network 4 via the communication I / F using a predetermined protocol.

  Next, the configuration of the terminal 3B will be described. The terminal 3B is a personal computer (PC), for example, and includes a display unit 15, an input unit 16, a storage unit 17, a communication I / F 18, a control unit 19B, and the like. The display unit 15 is composed of a liquid crystal display, for example, and displays image data and the like. The input unit 16 includes a keyboard, a mouse, and the like, and receives user operations. The storage unit 17 stores image data acquired from the image forming apparatus 2, a program executed by the control unit 19B, and the like.

  In the image forming system 1 of the first embodiment, main functions executed by the control unit 19B of the terminal 3 will be described. The encryption key generation processing unit 26 is an example of an encryption key generation unit, and generates a pair of encryption keys composed of a public key A and a secret key B. The encryption key storage unit 27 stores the encryption key generated by the encryption key generation processing unit 26. Of the encryption keys stored in the encryption key storage unit 27, the secret key B is sent to the decryption processing unit 28, and the public key A is sent to the communication processing unit 29.

  The communication processing unit 29 is an example of a communication unit, and transmits the public key A stored in the encryption key storage unit 27 to the network 4 via the communication I / F 18 using a predetermined protocol. Also, the image data transmitted from the image forming apparatus 2 to the network 4 is received via the communication I / F 18. The image data received by the communication processing unit 29 is stored in the storage unit 17. The decryption processing unit 28 is an example of decryption means, and decrypts the encrypted image data stored in the storage unit 17 with the secret key B stored in the encryption key storage unit 27. The image data decoded by the decoding processing unit 28 is displayed on the display unit 15, for example. Alternatively, it is stored in the storage unit 17.

  Note that the mechanism of the image forming apparatus 2B in the image forming system 1B of the second embodiment is the same as the configuration described in FIG. 2, for example. Further, the encryption method used in the image forming system 1B of the second embodiment is an asymmetric encryption method as in the first embodiment.

  FIG. 5 is a flowchart illustrating an operation example of the image forming system 1B according to the second embodiment. Hereinafter, a second example using an asymmetric encryption method as an image processing method of the image forming apparatus according to the present embodiment will be described. The operation of the image forming system 1B according to the embodiment will be described.

  First, the user operates the operation unit 7 of the image forming apparatus 2B shown in FIG. 4, registers a user ID, and secures a data storage area protected by the user ID in the image data storage area 8a of the storage unit 8 ( Step SB1). When the user scans an image to be kept secret, the user operates the input unit 16 of the terminal 3B to register the encrypted scan in the image forming apparatus 2B (step SB2).

  That is, the control unit 19B of the terminal 3B generates the public key A and the secret key B by the encryption key generation processing unit 26 (step SB3). The control unit 19B transmits the public key A among the encryption keys generated by the encryption key generation processing unit 26 to the electronic mail address of the image forming apparatus 2B registered in advance by the communication processing unit 29 (step SB4). Further, the control unit 19B stores the secret key B in the encryption key storage unit 27 (step SB5).

  When the communication processing unit 25 receives the public key A, the control unit 10B of the image forming apparatus 2B temporarily stores it in the encryption key storage unit 23 in association with the user ID (step SB6). The user may input the public key A by operating the operation unit 7 of the image forming apparatus 2B.

  The user operates the operation unit 7 of the image forming apparatus 2B to input a user ID, sets a document on the document tray 55 of the automatic document feeder 32 shown in FIG. 2, for example, and issues a scan start instruction ( Steps SB7 and SB8).

  Upon receiving an instruction to start scanning, the control unit 10B of the image forming apparatus 2B transports the document P1 set on the document tray 55, reads an image by the image sensor 40, and receives image data as an electrical signal from the scanner unit 5. Output (step SB9). The control unit 10B encrypts the image data output from the scanner unit 5 by the encryption processing unit 24 using the public key A stored in the encryption key storage unit 23 (step SB10). The control unit 10B stores the encrypted image data in the image data storage area 8a of the storage unit 8 in association with the user ID (step SB11).

  As described above, in the asymmetric encryption method, image data encrypted using the public key A cannot be decrypted using the public key A. Therefore, the image forming apparatus 2B cannot decrypt the encrypted image data stored in the storage unit 8.

  When using the image data stored in the image forming apparatus 2B, the user operates the input unit 16 of the terminal 3B, inputs a user ID, and issues an image data acquisition instruction (step SB12). Note that image data is extracted by a procedure such as FTP (File Transfer Protocol). Upon receiving an image data acquisition request from the terminal 3B, the control unit 10B of the image forming apparatus 2B reads the image data specified by the user ID from the image data storage area 8a of the storage unit 8, and the communication processing unit 25 performs the terminal processing. Transmit to 3B (step SB13).

  When the communication processing unit 29 receives the image data, the control unit 19B of the terminal 3B decrypts the encrypted image data by the decryption processing unit 28 using the secret key B stored in the encryption key storage unit 27. (Step SB14). The control unit 19B displays and outputs the decoded image data, for example, on the display unit 15 (step SB15).

  As described above, in the asymmetric encryption method, the image data encrypted using the public key A can be decrypted only using the secret key B. Therefore, only the terminal 3B of a specific user holding the secret key B can decrypt the image data and use it for display or the like.

  If the public key A and the secret key B are generated by the terminal 3B as in the second embodiment, the secret key B is less likely to be leaked to the outside, and the security can be further improved. .

  In the above description, the terminals 3 (A, B) are described as personal computers. However, the terminals 3 may be mobile terminals such as mobile phones and PDAs (personal digital assistants).

  Further, although the image forming apparatus 2 (A, B) and the terminal 3 are illustrated as being connected one-to-one, a plurality of terminals 3 are connected to one image forming apparatus 2 via the network 4. In the image forming system 1A according to the first embodiment, since the secret key and the image data are transmitted only to the terminal 3 specified by the user ID, another user can connect the image with the other terminal. Data cannot be retrieved. Further, since the image data is encrypted and the other terminal does not have a corresponding secret key, it cannot be read even if the image data is extracted.

  In the image forming system 1B according to the second embodiment, a secret key is generated for each terminal, and the encrypted image data is transmitted to the terminal 3 specified by the user ID. Cannot retrieve image data. In addition, since other terminals do not have a corresponding secret key, they cannot be read even if image data is extracted.

  Here, the public key A and the secret key B are generated every time an encrypted scan instruction is issued, and when an encrypted scan instruction for different jobs with the same user ID is issued, a new encryption key is generated.

  The image forming system 1 (A, B) according to the present embodiment obtains high security by using an asymmetric encryption method as an encryption method, but the same encryption key (encryption and encoding) It can also be realized by a symmetric encryption method using a shared key. That is, after the image forming apparatus 2 encrypts the image data, if the image forming apparatus 2 discards the shared key, the image forming apparatus 2 cannot decrypt the image data, and a specific terminal having the shared key Only 3 can decode image data.

1 is a block diagram illustrating a configuration example of an image forming system according to a first embodiment. 1 is an internal configuration diagram illustrating an example of an image forming apparatus. 3 is a flowchart illustrating an operation example of the image forming system according to the first embodiment. It is a block diagram which shows the structural example of the image forming system of 2nd Embodiment. 10 is a flowchart illustrating an operation example of the image forming system according to the second embodiment.

Explanation of symbols

1A, 1B Image forming system 2A, 2B Image forming apparatus 3A, 3B Terminal 4 Network 5 Scanner unit 6 Printer unit 7 Operation unit 8 Storage unit 8a Image data storage area 9 Communication I / F
10A, 10B Control unit 11 Encryption key generation processing unit 12 Encryption key storage unit 13 Encryption processing unit 14 Communication processing unit 15 Display unit 16 Input unit 17 Storage unit 18 Communication I / F
19A, 19B Control unit 20 Communication processing unit 21 Encryption key storage unit 22 Decryption processing unit 23 Encryption key storage unit 24 Encryption processing unit 25 Communication processing unit 26 Encryption key generation processing unit 27 Encryption key storage unit 28 Decryption processing unit 29 Communication processing unit

Claims (9)

In an image forming apparatus provided with a reading means for reading an image and connected to a network to which at least one terminal is connected,
Encryption key generation means for generating a pair of encryption keys for encrypting and decrypting image data;
Encryption means for encrypting image data with an encryption key used for encryption generated by the encryption key generation means;
Storage means for storing image data encrypted by the encryption means;
An image forming apparatus comprising: a communication unit that transmits an encryption key used for decryption generated by the encryption key generation unit to the terminal, and transmits the encrypted image data to the terminal. The encryption key generation means generates a secret key that is different from the public key used for encryption of image data and the decryption key used as an encryption key, and the encryption means encrypts image data using the public key. The image forming apparatus according to claim 1, wherein the communication unit transmits the secret key to the terminal. The terminal identification information is registered,
The image forming apparatus according to claim 1, wherein the communication unit transmits an encryption key used for the decryption and encrypted image data to a terminal specified by the identification information. In an image forming system in which an image forming apparatus having a reading unit for reading an image and at least one terminal are connected via a network,
The image forming apparatus includes:
Encryption means for encrypting image data using an encryption key generated by the terminal;
Storage means for storing image data encrypted by the encryption means;
Communication means for transmitting the image data encrypted by the encryption means to the terminal,
The terminal
Encryption key generation means for generating a pair of encryption keys for encrypting and decrypting image data;
Communication means for transmitting to the image forming apparatus an encryption key used for encryption generated by the encryption key generation means;
An image forming system comprising: decrypting means for decrypting the encrypted image data received from the image forming apparatus with an encryption key used for decryption generated by the encryption key generating means. The encryption key generation means generates a secret key different from the public key used for encryption of image data and the public key used for decryption as an encryption key,
The communication means of the terminal transmits the public key to the image forming apparatus,
The encryption means encrypts image data using the public key,
The image forming system according to claim 4, wherein the decryption unit decrypts the image data using the secret key. The terminal identification information is registered in the image forming apparatus,
The image forming system according to claim 4, wherein the communication unit of the image forming apparatus transmits the encrypted image data to the terminal specified by the identification information. The image forming system according to claim 4, wherein the terminal is a personal computer. The image forming system according to claim 4, wherein the terminal is a mobile terminal. In an image processing method of an image forming apparatus that reads an image and transmits image data as an electrical signal to a terminal via a network,
An image processing method for an image forming apparatus, comprising: encrypting image data using an encryption key designated by a user; and transmitting the encrypted image data to the terminal.

Images