Patent Publication Number: US-2006018472-A1

Title: Facsimile machine and facsimile communication method

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a facsimile machine and a facsimile communication method, and in particular, a facsimile machine and a facsimile communication method having a transmission data encryption function.  
      2. Description of Related Art  
      A facsimile machine having an electronic mail function encrypts data, creates electronic mail having the encrypted data as an attached file and transmits the created electronic mail to a remote device.  
      In general, when encrypting electronic mail, an encryption processing is carried out in accordance with a program handled in an application layer of a communication protocol, for example, the Secure/Multipurpose Internet Mail Extension (S/MIME). By carrying out such an encryption processing, security of the electronic mail at transmission can be improved.  
     SUMMARY OF THE INVENTION  
      Although demand exists for an improvement in security at transmission of electronic mail attached with data, since an advanced encryption processing such as the S/MIME imposes a load on hardware such as a Central Processing Unit (CPU) and a memory of a facsimile machine, a demand also exists for a facsimile machine which reduces such a load.  
      The present invention has been made in consideration of the above-described circumstances. An advantage of the present invention is to provide a facsimile machine which can prevent a load from being imposed on hardware such as a CPU and a memory in a processing at transmission of transmission data and ensures security in communication.  
      According to a first aspect of the present invention, a facsimile machine having a transmission data encryption function includes a plurality of encryption processing units, which respectively encrypt transmission data by different encryption methods, an encryption processing determination unit, which transmits the transmission data to either one of the plurality of the encryption processing units, and a transmitter, which transmits the encrypted transmission data.  
      According to such a facsimile machine, either one of the plurality of the encryption processing units having different encryption processing methods can be selected manually or automatically according to the transmission data. By changing a load imposed on the hardware such as the CPU and the memory for each of the encryption processing methods, a load can be prevented from being imposed on the hardware in the processing at the transmission of the transmission data and security in communication can be ensured.  
      According to a second aspect of the present invention, the encryption processing determination unit determines to transmit the transmission data to one of the encryption processing units in accordance with a transmission destination of the transmission data. The encryption processing determination unit may determine to transmit the transmission data to one of the encryption processing units in accordance with a communication form of the transmission data.  
      According to a third aspect of the present invention, an optimum encryption method can be used according to a transmission destination or a communication form. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       FIG. 1  shows a facsimile machine according to an embodiment of the present invention.  
       FIG. 2  is a block diagram showing functions implemented by a control unit, a Read Only Memory (ROM), a Random Access Memory (RAM), and according to necessity, a Modulator-Demodulator (MODEM) and a network interface.  
       FIG. 3  shows a structure of transmission destination data accumulated in a transmission destination database according to an embodiment of the present invention.  
       FIG. 4  is a flowchart showing an operation relating to an encryption processing of transmission data according to an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      In the following, with reference to the drawings, a detailed description will be made of a facsimile machine according to an embodiment of the present invention.  FIG. 1  shows a facsimile machine according to an embodiment of the present invention.  
      In a facsimile machine  10 , a control unit  12 , a scanning unit  14 , a printer unit  16 , a display unit  18 , an operation unit  20 , a Network Control Unit (NCU)  22 , a MODEM  24 , a ROM  26 , a RAM  28  and a network interface  30  are connected via a bus  11 .  
      The scanning unit  14  includes a line sensor and a Charge Coupled Device (CCD) or the like, which are not shown in the drawings. The scanning unit  14  scans an original document for facsimile transmission, loads the scanned original document as image data and encodes the image data. The scanning unit  14  accumulates the encoded image data and outputs the image data along with data relating to a transmission destination of the image data. The scanning unit  14  may be replaced by a remote computer device for creating image data.  
      The printer unit  16  includes an electrophotographic printing device, an inkjet printing device or the like. The printer unit  16  prints out a message received from another facsimile machine.  
      The display unit  18  is, for example, a Liquid Crystal Display (LCD) or a Cathode-Ray Tube (CRT) display. The display unit  18  displays an operational state of the facsimile machine  10 , a transmission message and a received message or the like.  
      The operation unit  20  includes keys necessary for operating the facsimile machine  10 . For example, the operation unit  20  includes keys such as a character key, a ten-key numeric pad and a speed dial key for specifying a transmission destination of the image data. The operation unit  20  also includes various function keys such as a key for designating an encryption method and a key for designating a transmission format. Alternatively, the display unit  18  can be formed of a touch screen and a part or all of the function keys of the operation unit  20  can be displayed on the touch screen to provide the display unit  18  as an operation unit.  
      The NCU  22  carries out a closing operation and a releasing operation of a Public Switched Telephone Network (PSTN). The NCU  22  includes a function for transmitting an address signal according to a telephone number of a destination and a function for detecting a ringing signal. The NCU  22  connects the MODEM  24  and the PSTN according to necessity.  
      The MODEM  24  functions as a faxmodem which can carry out general facsimile transmission. The MODEM  24  modulates transmission data and demodulates received data. Specifically, the MODEM  24  modulates transmission data into an audio frequency signal and transmits the audio frequency signal via the NCU  22  to the PSTN. The MODEM  24  demodulates the audio frequency signal received from the destination from the PSTN via the NCU  22  into a digital signal.  
      The ROM  26  previously stores a computer program and information necessary for facsimile transmission and reception. For example, the ROM  26  stores information relating to a function of each structure, an application program for creating electronic mail, a processing program of created electronic mail, a conversion program used in an encryption processing and a decryption processing and a program for decoding encoded image data received from a destination (not shown) of facsimile communication. Further, to respond easily to a correction or an addition of various control programs, a flash memory or the like, which is a rewritable nonvolatile memory, can be used in place of the ROM.  
      The RAM  28  is formed of a Static RAM (SRAM), a flash memory or the like. The RAM  28  stores temporary data that is generated at an operation of the control unit  12  executed in accordance with a program stored in the ROM  26 . The RAM  28  temporarily stores image data encoded by the scanning unit  14 .  
      The network interface  30  is an interface for establishing a connection between the facsimile machine  10  and a network such as a Local Area Network (LAN) and the Internet and transmitting electronic mail to a mail server to be described later.  
      The control unit  12  controls each operation and as to be described later, transmits encoded image data input from the scanning unit  14 , along with the ROM  26  and the RAM  28 . When attaching image data to electronic mail and transmitting the electronic mail, the control unit  12  carries out an encryption processing or the like on the electronic mail. Furthermore, the control unit  12  decodes the encoded image data received from a destination (not shown) of the facsimile communication.  
       FIG. 2  shows functional blocks implemented by the control unit  12 , the ROM  26 , the RAM  28  and according to necessity, the MODEM  24  and the network interface  30 .  
      The facsimile machine  10  includes a transmission data creating unit  42 , a transmission destination extracting unit  44 , an encryption processing determination unit  46 , a transmission destination database  48 , a transmitting and receiving unit  50 , a first encryption processing unit  52 , a connection control unit  54  and a second encryption processing unit  56 .  
      The transmission data creating unit  42  creates transmission data from image data transmitted from the scanning unit  14  and a transmission format designated by the operation unit  20 .  
      The transmission destination extracting unit  44  extracts data relating to the transmission destination from the created transmission data. The encryption processing determination unit  46  determines whether or not to encrypt the transmission data by referring to the transmission destination database  48  based on a transmission destination, for example, an individual address, a mail address or an Internet Protocol (IP) address, or based on a communication form, for example, whether or not to transmit via the mail server. The encryption processing determination unit  46  also determines to transmit the transmission data to which one of encryption processing units to be described later when encrypting the transmission data.  
      In the transmission destination database  48 , a previously registered transmission destination and an encryption method set according to each transmission destination are accumulated by being associated with one another. For example, as shown in  FIG. 3 , when the transmission destination is a mail address such as “pc@mailbox”, the S/MIME as a first encryption method to be described later is accumulated by being associated with the mail address. When the transmission destination is an IP address such as “192.168.1.1”, the Secure Sockets Layer (SSL) as a second encryption method to be described later is accumulated by being associated with the IP address. Furthermore, when the encryption method starts with the S/MIME, a public key can be accumulated as destination information by being associated with the encryption method.  
      In the first encryption processing unit  52 , when the transmission data transmitted from the encryption processing determination unit  46  is determined to be transmitted via a mail server  58  as to be described later, for example, the first encryption processing unit  52  encrypts the transmission data by the S/MIME method, the Pretty Good Privacy (PGP) method or the like, which is an extension of the encryption method MIME used in electronic mail data. Then, the first encryption processing unit  52  transmits the encrypted transmission data to the transmitting and receiving unit  50 .  
      When the transmission data transmitted from the encryption processing determination unit  46  is determined to be transmitted without through the mail server  58  as to be described later, the connection control unit  54  establishes a connection with another facsimile machine  40  through the Internet  60  from the transmitting and receiving unit  50  to be described later.  
      In the second encryption processing unit  56 , the transmission data transmitted from the encryption processing determination unit  46  through the connection control unit  54  is encrypted by an encryption method, which imposes smaller load on the hardware such as the CPU and the memory than the encryption method used in the first encryption processing unit  52 , for example, by the SSL or the Security Architecture for Internet Protocol (IPsec).  
      A description will be made of a combination of the encryption processing in the first encryption processing unit  52  and the encryption processing in the second encryption processing unit  56 . The first encryption processing unit  52  can adopt an encryption method in an application layer, for example, the S/MIME or the PGP method. The second encryption processing unit  56  can adopt an encryption method in a transport layer, for example, the SSL, or an encryption method in a network layer, for example, the IPsec.  
      The transmitting and receiving unit  50  transmits the transmission data encrypted by the first encryption processing unit  52  to the mail server  58 . Alternatively, the transmitting and receiving unit  50  transmits the transmission data encrypted by the second encryption processing unit  56  directly to the facsimile machine  40 , which is connected previously via the Internet  60 .  
      The mail servers  58  and  59  transmit and receive data transmitted from a facsimile machine. The mail servers  58  and  59  are connected to one another via the Internet  60 . A facsimile machine is connected to each of the mail servers  58  and  59 , respectively.  
       FIG. 4  is a flowchart showing an operation relating to the encryption processing of the transmission data according to the present embodiment. Further, an operation carried out in each step will be described by associating it with the structures shown in  FIG. 2 . After the transmission data is created by the transmission data creating unit  42 , at step S 10 , as described above, a transmission destination is extracted from the transmission data.  
      At step S 12 , by referring to the transmission destination database  48 , the encryption processing determination unit  46  determines whether or not the transmission data requires an encryption processing based on the transmission destination extracted at step S 10 .  
      When a determination result at step S 12  is NO, in other words, when a determination is made that the transmission data does not require an encryption processing, the process proceeds onto step S 14 . At step S 14 , a general transmission processing is carried out for the transmission data. That is, the transmission data is transmitted to the other facsimile machine  40  by the Simple Mail Transfer Protocol (SMTP) or the like used in a general transmission protocol and the data transmission operation ends.  
      When a determination result at step S 12  is YES, in other words, when a determination is made that the transmission data requires an encryption processing, the process proceeds onto step S 16 . At step S 16 , by referring to the transmission destination database  48 , the encryption processing determination unit  46  determines whether or not the transmission data has been planned to be transmitted via the mail server  58 . Further, the determination of step S 16  may be carried out together with the determination of step S 12 .  
      When a determination result at step S 16  is YES, in other words, when a determination is made that the transmission data is planned to be transmitted via the mail server  58 , the process proceeds onto step S 18 . At step S 18 , the first encryption processing unit  52  encrypts the transmission data by the S/MIME or the like. Then, the process proceeds onto step S 20 . The encrypted transmission data is converted into data, which can be transmitted through the Internet, and the converted data is transmitted to the mail server  58 . The data is further transmitted from the mail server  58  through the Internet  60  and eventually to the mail server  59 , which is connected to the facsimile machine  40  of the transmission destination. Then, the data transmission operation ends. Further, prior to the encryption processing of step S 18 , by referring to the table, a confirmation can be carried out as to whether or not a facsimile machine of a recipient can process the encrypted data. In this case, if the facsimile machine of the recipient can process encrypted data, an encryption processing can be carried out. If the facsimile machine of the recipient cannot process encrypted data, the processing can be interrupted and an error processing can be carried out.  
      When a determination result at step S 16  is NO, in other words, when a determination is made that the transmission data is not planned to be transmitted via the mail server  58 , the process proceeds onto step S 22 . At step S 22 , a connection with the facsimile machine  40  of the transmission destination is established from the connection control unit  54  and the process proceeds onto step S 24 . At step S 24 , the second encryption processing unit  56  executes the SSL encryption processing or the IPsec encryption processing on the transmission data. Then, the process proceeds onto step S 26 . At step S 26 , the transmission data created at step S 24  is transmitted directly to the facsimile machine  40  through the Internet  60  in accordance with a communication protocol in a network layer. Then, the data transmission operation ends.  
      At step S 22 , a connection with another facsimile machine is established. Also at step S 22 , a confirmation can be carried out as to whether or not the other facsimile machine has the same encryption function as the second encryption processing unit  56 . If a confirmation is made that the facsimile machine of the recipient can process the encrypted data, an encryption processing can be carried out. If a confirmation is made that the facsimile machine of the recipient cannot process the encrypted data, the processing can be interrupted and an error processing can be carried out. Alternatively, a format of the transmission data can be changed to another method which can be decrypted.  
      In the present embodiment, a transmission destination extracting unit is provided and according to data of the transmission destination, an encryption method is selected automatically. However, a user (an operator) can manually select the encryption method.  
      As described above, according to the present embodiment, either one of a plurality of encryption processing units having different encryption processing methods, for example, the first encryption processing unit or the second encryption processing unit, can be selected manually or automatically according to the transmission data. By changing the load imposed on the hardware such as the CPU and the memory for each of the encryption processing methods, a load can be prevented from being imposed on the hardware in the processing at the transmission of the transmission data and security in the communication can be ensured.  
      According to the above-described facsimile machine and the facsimile communication method, an optimum encryption method can be used according to a transmission destination or a communication form.