JP2008134985A - Network system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a network system capable of securely delivering an individually prepared public key certificate and ensuring security in the communication of e-mails. <P>SOLUTION: The network system comprises a plurality of digital multifunction machines 1 to which user terminals 2 are connected through LANs 3. The transmitting side digital multifunction machine 1a individually prepares a public key certificate 11, encodes the certificate 11 into a QR code 12 and transmits the QR code 12. The receiving side digital multifunction machine 1b receives the QR code 12b and decodes the QR code 12b into the public key certificate 11. The QR code 12 is securely transmitted through either one of a public telephone network and the Internet. A receiving side user terminal 2d downloads the public key certificate 11 from the digital multifunction machine 1b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a network system including a digital multi-function peripheral and a user terminal such as a personal computer connected to the digital multi-function peripheral via a LAN, and each digital multi-function peripheral is connected by a network, and security in electronic mail communication Regarding technology.

  With respect to the present invention, it is common to use electronic mail to send and receive electronic documents between personal computers connected to the Internet network. A so-called digital multifunction peripheral (MFP) having a plurality of functions such as a facsimile function, a copy function, and a scanner function is known. In addition to the conventional G3 facsimile communication, there is also a digital multi-function peripheral capable of Internet facsimile communication. Patent Document 2 discloses a technique that attempts to use a QR code for encryption.

JP 11-215383 A JP 2000-324095 A

  Since electronic documents sent and received using e-mail are transmitted via the Internet, there is a risk of interception of communication contents by third parties, impersonation of the sender, tampering of communication contents, etc., ensuring security during communication. It is an important issue. Therefore, recently, the use of cryptographic communication means such as S / MIME (Secure / Multipurpose Internet Mail Extensions) has improved the security at the time of sending e-mails.

  However, when such an encryption communication means is used, it is usually necessary to obtain a public key certificate issued by a third party certification authority, but the procedure is troublesome.

  Further, as described in Patent Document 1 above, as the public key is downloaded from a predetermined web page, the destination MUA (e-mail client) needs to have the source public key certificate in advance. . When creating a public key certificate independently of the certificate authority, the public key certificate as the certificate authority is concealed in order to prove that the public key certificate is authentic. It must be passed to the receiver in the state.

  The present invention provides a network system that can safely deliver a public key certificate without securing a public key certificate from a certificate authority, which is a third-party organization, and can ensure security during e-mail communication. The purpose is to do.

  The present invention includes a digital multi-function peripheral and a user terminal connected to the digital multi-function peripheral via a LAN. Each digital multi-function peripheral is connected to a public telephone line network, and facsimile communication is performed between the digital multi-function peripherals. A transmission side digital multifunction peripheral connected to the user terminal is configured to generate the user's public key and private key, and the user's first public key certificate as a certificate authority. A means for creating, a means for creating a second public key certificate of its own device as a certificate authority, a means for encoding the second public key certificate into an image code, and a second through a public telephone line network Means for transmitting the image code encoded with the public key certificate by facsimile communication, and the receiving digital multifunction peripheral connected to the user terminal passes through the public telephone line network. Means for receiving the image code encoded with the second public key certificate by means of the facsimile communication, and means for acquiring the second public key certificate by decoding the image code encoded with the second public key certificate; Means for storing the acquired second public key certificate, and a user terminal connected to the receiving digital multifunction peripheral accesses the receiving digital multifunction peripheral and stores the second public key certificate. A means for downloading a public key certificate is provided.

  The present invention also includes a digital multi-function peripheral and a user terminal connected to the digital multi-function peripheral via a LAN, each digital multi-function peripheral being connected to the Internet network, and an internet facsimile between the digital multi-function peripherals. In a network system in which communication is performed, a digital multi-function peripheral on a transmission side connected to a user terminal creates a user public key and secret key, and a first public key certificate of the user as a certificate authority Generating means, as a certificate authority, means for generating a second public key certificate of its own device, means for encoding the second public key certificate into an image code, and a second public key certificate using a password as a key Means for encrypting the image code in which the document is encoded, and means for transmitting the encrypted image code by attaching it to an e-mail. The terminal on the receiving side that is connected receives the e-mail and stores the image code encoded with the second public key certificate that is attached and encrypted, and the user inputs the password A means for decrypting the stored encrypted image code, a means for decoding the decrypted image code to obtain a second public key certificate, and an obtained second public key certificate And a means for a user terminal connected to the receiving digital multifunction peripheral to access the receiving digital multifunction peripheral and download the stored second public key certificate. ing.

  When the user terminal on the receiving side accesses the digital MFP on the receiving side and downloads the stored second public key certificate, the second public key certificate can be encrypted and downloaded.

  The image code includes a QR code.

  According to the present invention, each user's public key certificate is uniquely created by a digital multi-function peripheral to which a user terminal used by the user is connected. Therefore, it is not necessary for each user to go through the troublesome procedure of acquiring the user's public key certificate from a certificate authority, which is a third-party organization, in order to use it for communication within the network.

  In order to prove that the user's first public key certificate is authentic, the second public key certificate created by the digital multifunction peripheral as a certificate authority is once encoded into an image code by the digital multifunction peripheral on the transmission side. Since the image code is decoded into the second public key certificate by the digital MFP on the receiving side, the second public key certificate in the communication process is converted into the image code. The second public key certificate can be delivered safely.

  The digital MFP on the receiving side stores the acquired second public key certificate. Each user terminal connected to the digital multi-function peripheral via a LAN can download the second public key certificate by accessing the digital multi-function peripheral. This makes it easy to obtain the second public key certificate of the certificate authority (digital multi-function peripheral) that proves that the public key certificate used between the user terminals is authentic.

  The second public key certificate is transmitted / received between the digital MFPs by conventional facsimile communication using the public telephone line network, so that the public telephone line network is secured at the time of communication. The key certificate can be sent securely. It is safe because the destination and destination are specified by telephone numbers.

  Even when sending and receiving the second public key certificate between the digital multifunction peripherals via the Internet, the second public key certificate is encoded into an image code and the password is keyed by the digital multifunction peripheral on the transmission side. After the image code is encrypted, it is sent as an e-mail attachment. Then, in the receiving digital multi-function peripheral, the destination user inputs the password to decrypt the encrypted image code and to decode the decrypted image code into the second public key certificate. In this case, even if a third party intercepts the information, the second public key certificate can be safely delivered because it is difficult to decipher because the double secret processing is performed with different technologies.

  When the user terminal accesses the digital multi-function peripheral and downloads the second public key certificate, it is possible to further improve security if communication is performed with encryption.

  If a QR code is used for an image code, a large amount of information can be recorded in a small area, so that an image to be transmitted / received is reduced accordingly, which is effective in suppressing communication cost and shortening the input / output time of the image.

  Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, the network system of the present invention includes a plurality of digital multi-function peripherals 1,... 1 connected to the Internet network and a public telephone line network (PSTN), and these digital multi-function peripherals via LANs. Are connected to a plurality of user terminals 2. Here, in order to simplify the description, the digital multi-function peripheral 1 is indicated by two transmitters 1a and 1b, and the user terminals 2 connected to the respective digital multi-function peripherals 1a and 1b are indicated by three. It was. Note that not all of the digital multifunction peripheral 1 is necessarily connected to the user terminal 2. The number of connected user terminals 2 is not necessarily plural, and includes one case.

  The digital multi-function peripheral 1 is a multi-function device called an MFP having a copy function, a printer function, a scanner function, a facsimile function, a network function, and the like. As a facsimile function, in addition to a so-called G3 facsimile communication function via a conventional public telephone line network, an Internet facsimile communication function via an Internet network is also provided.

  The user terminal 2 is a so-called known personal computer (PC), and includes a monitor, a PC main body, and the like.

  The digital multifunction device 1 and the user terminal 2 are connected via a LAN 3 to form one network. This network is connected to the Internet via a router 4, and the digital multi-function peripheral 1 can use this to perform Internet facsimile communication, and the user terminal 2 can use this to perform communication by electronic mail. It has become.

  FIG. 2 is a block diagram for explaining the configuration of the digital multi-function peripheral 1. The digital multifunction device 1 includes a security information processing unit 5, an image code processing unit 6, a file processing unit 7, a user information management unit 8, a facsimile communication unit 9, and an Internet facsimile communication unit 10. All of these are realized by devices such as a CPU, RAM, HDD, and modem mounted in the digital multi-function peripheral 1. In addition, although not shown, an operation unit including a touch panel, a printer, and a reading device that reads a document such as a document are also provided.

  The security information processing unit 5 performs information processing for ensuring security at the time of transmission / reception of electronic information using a public key encryption method. Specifically, a process for creating a public key (PK) and a secret key (SK) paired with the public key, a process for encrypting electronic information with the public key, and a pair with the secret key with the secret key A process of decrypting the electronic information encrypted with the public key and a process of creating a public key certificate (PKC) 11 for proving the issuer of the public key are performed. That is, since the digital multi-functional peripheral 1 of the present invention has a function of creating a public key certificate 11 uniquely, each user is purposely made public from a certificate authority, which is a third party, with regard to encrypted communication within the network. The troublesome procedure of obtaining a key certificate is no longer necessary.

  The image code processing unit 6 performs a conversion process between the electronic information and the image code 12. Specifically, as shown in FIG. 3, the process of encoding the second public key certificate 11b, which is electronic information created by the security information processing unit 5, into a QR code (image code) 12, or from the QR code 12 A process of decoding into the second public key certificate 11b is performed. By converting the communication process to the QR code 12, the second public key certificate 11b can be transmitted and received safely. The image code means an identification code represented by an image like the QR code 12 shown in the present embodiment.

  By using the second public key certificate 11b as the QR code 12 which is image information, facsimile transmission using a conventional public telephone line network in which security is ensured becomes possible. This is because facsimile communication is a proven communication means suitable for image processing, and a reliable and highly accurate communication environment can be obtained by encoding the QR code 12 for communication. Even when transmitting via the Internet, in addition to the conventional password encryption, a double secret process is performed by image coding, which is a separate technology. it can.

  The file processing unit 7 performs processing for encrypting or decrypting the QR code 12 using the password as a key, processing for storing the encrypted QR code 12 in the PDF file 13, and processing for retrieving from the stored PDF file 13. .

  The user information management unit 8 has a database function, and performs processing for managing user electronic information. For example, in the database, the mail address of the user who uses each user terminal 2 connected to the digital multifunction device 1 is registered, and the public key, the private key, the public key certificate are associated with the mail address. Electronic information such as a document 11 is stored, and a series of information processing is performed in cooperation with the security information processing unit 5 and the file processing unit 7.

  The user information management unit 8 has a Web server function. With the Web server function, the digital multi-function peripheral 1 provides a user interface using the Web to the user terminal 2 connected thereto. For example, each user terminal 2 that is a client connected via the LAN 3 accesses the digital multi-function peripheral 1 that is the connected server, and information on the stored public key and public key certificate 11. You can search and browse and download them as needed. It is also possible to instruct the security information processing unit 5 to create a public key or a public key certificate 11 from a browser input screen displayed on the monitor of the user terminal 2.

  HTTP (Hypertext Transfer Protocol) is used as a browser protocol. When at least the second public key certificate 11b is downloaded, SSL (Secure Socket Layer) that is an encryption function is used (HTTP over SSL), and between the digital MFP 1 and the user terminal 2 is used. The communication is encrypted. That is, HTTPS (Hypertext Transfer Protocol Security) was used as a protocol for downloading the second public key certificate 11b. Therefore, the communication of the second public key certificate 11b between the digital multi-function peripheral 1 and the user terminal 2 is further performed by encrypting in addition to the communication within the LAN 3 which is a limited network. Security is enhanced.

  The facsimile communication unit 9 is connected to a public telephone line network, and performs processing for transmitting and receiving image information such as a document by so-called G3 facsimile communication.

  The Internet facsimile communication unit 10 performs processing for transmitting and receiving image information such as a document using electronic mail. That is, it has a so-called Internet facsimile communication function for transmitting and receiving the read image information attached to an e-mail via the Internet network. In addition, the PDF file 13 created by the file processing unit 7 is attached to the electronic mail 14 and transmitted / received.

  In the network system of the present embodiment, the second public key certificate 11b that proves that the user's public key or the first public key certificate 11a that is uniquely created by the digital MFP 1 on the transmission side is authentic. Can be selected and communicated between the route using the public telephone line network and the route using the Internet network in order to safely and reliably pass the message to the digital MFP 1 on the receiving side. It is like that. Hereinafter, a series of processes for transferring the second public key certificate 11b from the transmission-side user terminal 2a to the reception-side user terminal 2d in FIG. The first public key certificate 11a of the user is transmitted / received by attaching an electronic signature of the digital multi-function peripheral 1a as a certificate authority and attaching it to an e-mail.

{Route using public telephone network}
4 and 6 to 8 show a schematic diagram and a processing flowchart for a route using the former public telephone network (PSTN network).

  In each of the digital multifunction peripherals 1a and 1b, a mail address of a user who uses the user terminal 2 connected to the digital multifunction peripheral 1 is registered. Based on the registered user's e-mail address, the user information management unit 8 creates a data storage unit related to the user and stores it in the database. For example, in the case of the digital MFP 1a on the transmission side in FIG. 1, the mail addresses of users who use the user terminals 2a, 2b, and 2c are registered, and a data storage unit is created.

  For example, the user creates a public key (PK) / private key (SK) for encryption communication and public key certificate (PKC) for the user from the display screen of the browser displayed on the monitor of the user terminal 2a on the transmission side. When the creation of 11 is instructed, the digital MFP 1a on the transmitting side independently uses a user key based on the public key cryptosystem by the cooperation of the security information processing unit 5 and the user information management unit 8 and the like. Public key and private key, and a first public key certificate 11a are created. Then, in the digital multifunction peripheral 1a, the second public key certificate 11b is created as a certificate authority (step S1). The second public key certificate 11b proves that the user's first public key certificate 11a is authentic based on the electronic signature attached to the first public key certificate 11a. The public key / private key and the public key certificate 11 are stored in a predetermined data storage unit of the database in association with the mail address possessed by the user. The public key and the first public key certificate 11a are, for example, sent directly from the user terminal 2a used by the sending user to the user terminal 2d used by the sending destination user by attaching it to an e-mail. It is sent by the method of. However, the digital signature of the digital multifunction peripheral 1a is attached to the first public key certificate 11a. The user's private key is held in a secret state so that only the user on the transmission side can use it.

  Then, the second public key certificate 11b of the digital multifunction peripheral (certificate authority) 1a is encoded into the QR code 12a by the image code processing unit 6 as shown in FIG. 3 (step S2).

  The QR code 12a encoded with the second public key certificate 11b is transmitted by G3 facsimile communication to the receiving digital multifunction peripheral 1b to which the destination user terminal 2d is connected (step S3). At this time, since both the transmission destination and the reception destination are specified by the telephone number, it is safe. Facsimile communication is a proven communication means suitable for image processing, and a reliable and highly accurate communication environment can be obtained.

  The digital MFP 1b on the receiving side receives the QR code 12b in which the second public key certificate 11b is encoded from the digital MFP 1a on the transmitting side by G3 facsimile communication via the public telephone line network (step S11). With a QR code, a large amount of information can be recorded in a small area, and the amount of images to be transmitted and received is small, which is effective in reducing communication costs and shortening the input / output time of images.

  Next, the QR code 12b is decoded into the second public key certificate 11b by the image code processing unit 6 of the receiving digital multifunction peripheral 1b, and the receiving digital multifunction peripheral 1b receives the second public key certificate 11b. Is acquired (step S12).

  The acquired second public key certificate 11b is stored and saved in the database of the user information management unit 8 of the digital MFP 1b on the receiving side (step S13). By storing the second public key certificate 11b in the digital multi-function peripheral 1b, the user terminal 2d that has transferred the user terminal 2a and the first public key certificate 11a only accesses the digital multi-function peripheral 1b thereafter. Thus, the second public key certificate 11b of the digital multifunction peripheral (certificate authority) 1a can be acquired. Therefore, the user terminal 2d obtains the second public key certificate 11b, and the user's public key certificate 11 is authentic based on the electronic signature attached to the user's first public key certificate 11a. You can prove that there is.

  The user who is the destination of the first public key certificate 11a accesses the digital MFP 1b on the receiving side from the browser screen displayed on the monitor of the user terminal 2d, and stores the second public stored from the e-mail address or the like. The key certificate 11b is searched and downloaded (step S21). At this time, the communication at the time of download is strengthened by using HTTPS (HTTP over SSL) which is an encrypted protocol.

  The downloaded second public key certificate 11b is automatically incorporated into the MUA (electronic mail client) of the user terminal 2d (step S22).

  Through the above processing, the second public key certificate 11b of the digital multifunction peripheral 1a (certificate authority) is sent to the second public key certificate 11b on the receiving side by the conventional facsimile function. Can be safely and reliably delivered to the user terminal 2d connected to the.

{Routes using the Internet network}
FIG. 5 and FIGS. 9 to 11 show a schematic diagram and a processing flowchart for a route using the latter Internet network.

  In FIG. 9, the processing from step S31 in which the registration of the mail address and creation of the data storage unit to step S32 in which the second public key certificate 11b is encoded into the QR code 12a is performed as described above. Since it is the same as the processing from step S1 to step S2 of the route using the network, the description is omitted.

  When the second public key certificate 11b is encoded into the QR code 12a, a password is set by the user on the transmission side, for example, via the browser screen of the monitor of the user terminal 2a in order to encrypt the QR code 12a. (Step S33).

  When the password is set, the QR code 12a is encrypted by the file processing unit 7 using the set password as a key and stored in the PDF file 13a (step S34).

  The obtained PDF file 13a is attached to an e-mail 14a destined for the receiving-side digital multifunction peripheral 1b to which the destination user terminal 2d is connected, and is transmitted to the mail server via the Internet via SMTP. (Step S35).

  The receiving digital multifunction peripheral 1b receives the electronic mail 14b sent from the transmitting digital multifunction peripheral 1a via the Internet by the POP3 from the mail server (step S41).

  Through the cooperative processing of the file processing unit 7 and the user information management unit 8 of the digital multifunction peripheral 1b on the receiving side, the PDF file 13b including the encrypted QR code 12b is extracted from the received electronic mail 14b, and the digital multifunction peripheral It is stored in 1b (step S42).

  The user on the receiving side acquires the password from the user on the transmitting side, for example, by verbal communication by telephone, and inputs it through the browser screen of the monitor of the user terminal 2d (step S43).

  When the password is input, the digital MFP 1b on the receiving side uses the file processing unit 7 to decrypt the saved PDF file 13b using the password as a key (step S44).

  The processing from Step S45 for obtaining the second public key certificate 11b from the QR code 12b of FIGS. 10 and 11 to Step S52 for incorporating the second public key certificate 11b into the MUA of the user terminal 2d has been described above. Since this is the same as Step S12 and Step S13, Step S21 and Step S22 of the route using the public telephone line network, description thereof is omitted.

  Through the above processing, the second public key certificate 11b of the digital multi-function peripheral (certificate authority) 1a is sent to the receiving-side digital multi-function peripheral 1b, which is the destination of the second public key certificate 11b, by the Internet facsimile function. It can be safely and reliably delivered to the connected user terminal 2d.

  The user terminal 2d incorporating the second public key certificate 11b into the MUA sends an encryption such as S / MIME to the destination of the mail address associated with the public key certificate 11, that is, the user using the user terminal 2a on the transmission side. It is possible to send mail using communication means. It is not necessary to go through the troublesome procedure of acquiring the public key certificate 11 from a certificate authority, which is a third-party organization, for use in communication within the network, and a simple network system can be constructed.

  As the image code 12, a two-dimensional code other than the QR code can also be used. It may be a one-dimensional code such as a barcode. In the present embodiment, a system connected to a public telephone line network and an Internet network is shown. However, when the second public key certificate 11b is transmitted by a route using the Internet network, the public telephone line network is not necessarily used. Not necessary.

It is the schematic of the network system of this invention. 2 is a block diagram for explaining a configuration of a digital multi-function peripheral. FIG. It is explanatory drawing of the function of an image code process part. It is the schematic of the route | root which uses a public telephone line network. It is the schematic of the route | root which uses an internet network. It is a processing flowchart figure of the transmitter in the route using a public telephone line network. It is a process flowchart figure of the receiver in the route | root which uses a public telephone line network. It is a process flowchart figure of the receiver side PC in the route | root which uses a public telephone line network. It is a process flowchart figure of the transmitter in the route which uses an internet network. It is a process flowchart figure of the receiver in the route | root which uses an internet network. It is a process flowchart figure of the receiver side PC in the route | root which uses an internet network.

Explanation of symbols

1 Digital MFP 2 User terminal 3 LAN
5 Security Information Processing Unit 6 Image Code Processing Unit 7 File Processing Unit 8 User Information Management Unit 9 Facsimile Communication Unit 10 Internet Facsimile Communication Unit 11 Public Key Certificate 11a First Public Key Certificate 11b Second Public Key Certificate 12 Image Code (QR code)
13 PDF file 14 E-mail

Claims (4)

A network comprising a digital multifunction peripheral and a user terminal connected to the digital multifunction peripheral via a LAN, wherein each digital multifunction peripheral is connected to a public telephone line network, and facsimile communication is performed between the digital multifunction peripherals. A system,
The digital MFP on the sending side connected to the user terminal
A means of creating the user's public and private keys;
Means for creating a user's first public key certificate as a certificate authority;
Means for creating a second public key certificate of its own device as a certificate authority;
Means for encoding the second public key certificate into an image code;
Means for transmitting the image code encoded with the second public key certificate by facsimile communication via a public telephone network;
With
The receiving digital multifunction peripheral connected to the user terminal
Means for receiving an image code encoded with a second public key certificate by facsimile communication via a public telephone network;
Means for decoding the image code encoded with the second public key certificate to obtain the second public key certificate;
Means for storing the acquired second public key certificate;
With
The user terminal connected to the digital MFP on the receiving side
A network system comprising means for accessing a digital MFP on the receiving side and downloading a stored second public key certificate. A network system comprising a digital multifunction peripheral and a user terminal connected to the digital multifunction peripheral via a LAN, wherein each digital multifunction peripheral is connected to the Internet network, and Internet facsimile communication is performed between the digital multifunction peripherals Because
The digital MFP on the sending side connected to the user terminal
A means of creating the user's public and private keys;
Means for creating a user's first public key certificate as a certificate authority;
Means for creating a second public key certificate of its own device as a certificate authority;
Means for encoding the second public key certificate into an image code;
Means for encrypting the image code encoded with the second public key certificate using the password as a key;
Means for sending an encrypted image code attached to an email;
With
The receiving terminal connected to the user terminal
Means for receiving an e-mail and storing an image code encoded and encoded with a second public key certificate attached thereto;
Means for decrypting the stored encrypted image code upon input of a password by the user;
Means for decoding the decrypted image code to obtain a second public key certificate;
Means for storing the acquired second public key certificate;
With
The user terminal connected to the digital MFP on the receiving side
A network system comprising means for accessing a digital MFP on the receiving side and downloading a stored second public key certificate. The network system according to claim 1 or 2, wherein
A network system that encrypts and downloads a second public key certificate when a user terminal on the receiving side accesses the digital multifunction peripheral on the receiving side and downloads the stored second public key certificate. A network system according to any one of claims 1 to 3,
A network system in which the image code includes a QR code.

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