JP2007324710A - Electronic mail communication system, electronic mail information encryption apparatus, and electronic mail transmission terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic mail communication system automatically executing encryption of an electronic document attached to electronic mail and capable of transmitting the electronic mail, an electronic mail information encryption apparatus for realizing it, and an electronic mail transmission terminal. <P>SOLUTION: The electronic mail communication system is configured to include: the electronic mail transmission terminal for creating electronic mail with an electronic document and transmitting the electronic mail with control information associated with control of encryption of the attached electronic document; the electronic mail information encryption apparatus connected to the electronic mail transmission terminal and provided with an encryption processing section applying automatic encryption to the electronic document attached to the electronic mail transmitted from a mail server function section on the basis of the control information attached to the electronic mail; and an electronic mail reception terminal for receiving the electronic mail. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an e-mail communication system, an e-mail information encryption apparatus, and an e-mail transmission terminal apparatus for protecting e-mail information, and in particular, by automatically encrypting an electronic document attached to an e-mail. The present invention relates to an electronic mail communication system for protecting electronic mail information, an electronic mail information encryption apparatus and an electronic mail transmission terminal apparatus for realizing the electronic mail communication system.

  In recent years, an electronic mail communication system via a network such as the Internet has been established as a very general communication means, and information is communicated by attaching an electronic document to the electronic mail. When sending and receiving e-mail, from the viewpoint of information security, the attached electronic document is encrypted in order to prevent the contents of the electronic document attached to the e-mail from being intercepted by a third party. ing. As described above, when an encrypted electronic document is transmitted by being attached to an electronic mail, it is necessary that the sender himself / herself encrypts and transmits the electronic document.

JP 2005-141294 A

  However, according to the conventional method, the terminal device used by the sender must have a function of encrypting the electronic document. That is, there is a problem that an electronic document encrypted by electronic mail cannot be transmitted from a terminal device that does not have a function of encrypting the electronic document. In addition, according to the conventional method, since it is necessary to encrypt the electronic document according to the intention of the sender, forgetting to encrypt becomes a problem.

  Various techniques relating to e-mail control have been proposed. For example, a technique for providing control information and controlling the transfer of e-mail has been proposed (see, for example, Patent Document 1). However, this technology controls the transfer of the e-mail itself (forwarding destination, transfer permission time, etc.), and the e-mail encryption must be performed manually by the sender, forgetting to encrypt it. Can not be prevented.

  The present invention has been made in view of the above, and an e-mail communication system capable of automatically encrypting an electronic document attached to an e-mail and protecting the information of the electronic document. An object of the present invention is to obtain an e-mail information encryption device and an e-mail transmission terminal device that realize the above.

  In order to solve the above-described problems and achieve the object, an electronic mail communication system according to the present invention creates an electronic mail attached with an electronic document, and transmits control information related to the control of encryption of the attached electronic document. An e-mail transmission terminal device that is attached to an e-mail and transmitted, a mail server function unit that is connected to the e-mail transmission terminal device and has a mail server function for e-mail, and mail based on control information provided to the e-mail An encryption processing unit that automatically encrypts an electronic document attached to an e-mail transmitted from the server function unit, and a history information management unit that manages history information related to transmission / reception of an e-mail in which the electronic document is encrypted A database for storing history information, and an encrypted electronic document attached to an e-mail and sent to the mail server function unit Both are connected to the electronic mail information encryption apparatus via a network, and an electronic mail information encryption apparatus comprising a control unit that controls the entire apparatus relating to automatic encryption of electronic document information attached to the electronic mail. And an e-mail receiving terminal device that receives an e-mail attached with an electronic document that has been subjected to an automatic encryption process in the e-mail information encryption device.

  According to the present invention, an electronic document can be automatically encrypted with respect to an electronic document attached to an electronic mail. As a result, even when an electronic mail attached with an electronic document is transmitted from a terminal device that does not have the function of encrypting the electronic document, the electronic document is automatically encrypted and attached to the electronic mail. The effect is that the document information can be protected. Further, even when the user forgets to encrypt the electronic document, the electronic document is automatically encrypted, and the information of the electronic document attached to the electronic mail can be protected.

  Embodiments of an electronic mail communication system, an electronic mail information encryption device, and an electronic mail transmission terminal device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably.

Embodiment FIG. 1 is a diagram showing a schematic configuration of an electronic mail communication system according to an embodiment of the present invention. The e-mail communication system according to the present embodiment is an e-mail communication system that protects e-mail information, and in particular, e-mail information is protected by automatically encrypting an electronic document attached to the e-mail. An electronic mail communication system.

  As shown in FIG. 1, the electronic mail communication system according to the present embodiment includes an electronic mail transmission terminal device 1, an electronic mail information encryption device 3, a network 5, and an electronic mail reception terminal device 7. Composed.

  The e-mail transmission terminal device 1 is a terminal device that can create an e-mail, attach an electronic document to the e-mail, and transmit it to the e-mail receiving terminal device 7 of a desired destination via the network 5. In the electronic mail transmitting terminal device 1, when creating an electronic mail, control information including importance information indicating the security importance of the electronic document attached to the electronic mail is given. Details of the control information will be described later.

  Such an electronic mail transmission terminal device 1 can be realized by executing a function (software) for creating an electronic mail in a calculation device such as a general-purpose personal computer. Note that the electronic document can be encrypted and attached to the electronic mail in the electronic mail transmitting terminal device 1.

  The electronic mail information encryption device 3 is connected to the electronic mail transmission terminal device 1 via a communication line 9 and is connected to the network 5 via a communication line 11. As shown in FIG. 1, the electronic mail information encryption device 3 includes a mail server function unit 101, a control unit 102, an encryption processing unit 103, a history information management unit 104, a database 105, and a file server function unit. 106 and an authentication server function unit 107.

  The mail server function unit 101 has a mail server function of receiving an electronic mail transmitted from the electronic mail transmitting terminal device 1 and transmitting the electronic mail to the network 5. The control unit 102 performs overall control of the electronic mail information encryption apparatus 3 for protecting the information of the electronic document attached to the electronic mail.

  The encryption processing unit 103 encrypts the electronic document attached to the electronic mail based on the control information given to the electronic mail transmitted from the electronic mail transmitting terminal device 1. This control information includes importance level information indicating the importance level of the electronic document attached to the electronic mail, and the electronic document is encrypted based on this information.

  The history information management unit 104 manages history information related to transmission / reception of an electronic mail in which an attached electronic document is encrypted, and performs, for example, storage processing and retrieval processing of the history information. The database 105 stores history information regarding transmission / reception of electronic mail in which the attached electronic document is encrypted. The file server function unit 106 registers and stores the encrypted electronic document. The authentication server function unit 107 controls access to the file server function unit 106.

  Such an e-mail information encryption device 3 has a function (software) for the function of the e-mail information encryption device 3 according to the present embodiment in a computing device such as a general-purpose personal computer having a CPU and recording means. It can also be realized by executing.

  The e-mail receiving terminal device 7 is connected to the network 5 via the communication line 13 and receives the e-mail transmitted from the e-mail transmitting terminal device 1 via the network 5. Such an electronic mail transmitting terminal device 1 can be realized by executing a function for creating an electronic mail in a general-purpose personal computer, for example.

  Here, for convenience of explanation, the e-mail transmitting terminal device 1 and the e-mail receiving terminal device 7 are described as different devices. However, in actual operation, the functions of these two devices are combined. The terminal device can function as the email sending terminal device 1 when sending an email, and can function as the email receiving terminal device 7 when receiving an email.

  Next, an e-mail communication method in the e-mail communication system according to this embodiment configured as described above will be described with reference to FIGS. 2-1 to 2-4. FIGS. 2-1 to 2-4 are flowcharts for explaining the processing flow in the electronic mail information encryption apparatus 3.

  First, processing in the control unit 102 will be described with reference to FIG. A user (sender) creates an e-mail attached with an electronic document in the e-mail transmission terminal apparatus 1 and transmits it to the e-mail receiving terminal apparatus 7 of a desired destination. Control information for controlling the encryption processing of the electronic document attached to the electronic mail is given to the electronic mail as control information.

  The control information includes importance level information indicating the importance level of the electronic document attached to the e-mail. Security importance is classified into three ranks, for example, “Low”, which is a low level of importance, “Normal”, which is a medium level, and “High”, which is a high level. The control information includes any one of these three importance information and “no importance information designation” as importance information indicating the security importance of the electronic document attached to the e-mail. is described.

  The above three pieces of importance information are given to the email as control information when the user (sender) designates the importance information when creating the email. Further, “no importance information designation” is automatically given to the electronic mail as control information when the user (sender) does not designate the importance information when creating the electronic mail.

  That is, the importance information of “Low”, “Normal”, and “High” is obtained by the user (sender) when the user (sender) creates an email in the email transmission terminal device 1. This is importance level information given to an e-mail by performing an instruction operation to be selected and given to the e-mail.

  On the other hand, when the user (sender) creates an e-mail in the e-mail transmission terminal device 1, the user (sender) selects the importance information and gives it to the e-mail. This is importance level information that is automatically given to an e-mail in the e-mail transmission terminal device 1 when no instruction operation is performed.

  For example, the user (sender) gives an instruction to select “importance” from “Low”, “Normal”, and “High” on the email creation instruction screen of the email sending terminal device 1 as shown in FIG. Importance information can be given to an e-mail by inputting to the e-mail transmission terminal device 1. FIG. 3 is a diagram illustrating an example of an e-mail creation instruction screen of the e-mail transmission terminal device 1.

  FIG. 4 is a diagram illustrating an example of control information given to an electronic mail transmitted by a user (sender). The control information to be given is described in, for example, XML (Extensible Markup Language), and the sender uses the dedicated e-mail transmission software as an e-mail transmission terminal device 1 or an e-mail using an extended function of the existing e-mail transmission software. Automatically generated by creating

  Among such control information, what is essential for controlling the encryption of an electronic document, which will be described later, is a <File Name> element and a <Control Level> element for specifying the electronic document, and <Control Level> The element corresponds to the importance information described above. The <Control Level> element specifies the importance of the electronic document attached to the e-mail. In this embodiment, as will be described later, encryption of an electronic document attached to an electronic mail is controlled according to the importance information.

  In FIG. 4, control information includes <Control Data> element, <From> element, <to> element, <CC> element, <BCC> element, <File Name> element, and <Control Level> element is described, but there are two essential elements that are attached as control information when creating an e-mail: <File Name> element and <Control Level> element. Other elements may be obtained from an e-mail when necessary in a later step.

  The electronic mail transmitted from the electronic mail transmitting terminal device 1 is first transmitted to the electronic mail information encryption device 3 via the communication line 9.

  In the electronic mail information encryption device 3, when the electronic mail is received by the mail server function unit 101, the electronic mail is transmitted to the control unit 102. When the control unit 102 receives the electronic mail transmitted from the mail server function unit 101 (step S101), the control unit 102 determines whether an electronic document is attached to the electronic mail (step S102).

  If no electronic document is attached to the e-mail (No at step S102), the control unit 102 transmits the e-mail to the mail server function unit 101 because there is no need to perform an electronic document encryption process ( Step S103). The mail server function unit 101 receives the electronic mail transmitted from the control unit 102 and transmits the electronic mail to the network 5 via the communication line 11. Thereby, the e-mail transmission process in the e-mail information encryption apparatus 3 is completed.

  The e-mail transmitted from the mail server function unit 101 is received by the e-mail receiving terminal device 7 of a predetermined destination via the communication line 11, the network 5, and the communication line 13.

  On the other hand, returning to step S102, if an electronic document is attached to the e-mail (Yes at step S102), the control unit 102 determines whether the electronic document attached to the e-mail is encrypted (step S102). Step S104). If the electronic document attached to the e-mail is encrypted (Yes at step S104), the control unit 102 sends the e-mail to the mail server function unit 101 because it is not necessary to perform an encryption process on the electronic document. (Step S103).

  The mail server function unit 101 receives the electronic mail transmitted from the control unit 102 and transmits the electronic mail to the network 5 via the communication line 11. Thereby, the e-mail transmission process in the e-mail information encryption apparatus 3 is completed.

  The e-mail transmitted from the mail server function unit 101 is received by the e-mail receiving terminal device 7 of a predetermined destination via the communication line 11, the network 5, and the communication line 13.

  On the other hand, returning to step S104, if the electronic document attached to the e-mail is not encrypted (No at step S104), the control unit 102 transmits the e-mail to the encryption processing unit 103 (step S105).

  When the encryption processing unit 103 receives the e-mail transmitted from the control unit 102 (step S201), the security importance of the electronic document attached to the e-mail is low from the control information given to the e-mail. It is confirmed whether or not it is “Low” (step S202). Specifically, for example, when the encryption processing unit 103 receives the email transmitted from the control unit 102, the encryption processing unit 103 extracts and analyzes the control information described in XML attached to the email, and analyzes the email from the content. It is confirmed whether or not the importance level information indicating the security importance level of the electronic document attached to is “Low”, which is a low level of importance level.

  Here, the control information includes importance information indicating the security importance of the electronic document attached to the electronic mail as described above. Security importance is classified into three ranks, for example, “Low”, which is a low level of importance, “Normal”, which is a medium level, and “High”, which is a high level. The control information includes any one of these three importance information and “no importance information designation” as importance information indicating the security importance of the electronic document attached to the e-mail. is described.

  Whether the importance information indicating the security importance of the electronic document attached to the e-mail is “Low”, which is a low level of importance, is determined based on the security importance of the electronic document. This is because the electronic document is not automatically encrypted when “Low”. In the present embodiment, when the importance information included in the control information is “Low”, the electronic document is not automatically encrypted, and the importance information included in the control information is “Normal” or “High”. Only when “no importance level information is specified”, the electronic document is automatically encrypted.

  Therefore, when the security importance level of the electronic document attached to the e-mail is “Low” (Yes in step S202), the encryption processing unit 103 transmits the e-mail to the control unit 102. (Step S203). The control unit 102 receives the e-mail transmitted from the encryption processing unit 103 and transmits the e-mail to the mail server function unit 101 (step S103).

  The mail server function unit 101 receives the electronic mail transmitted from the control unit 102 and transmits the electronic mail to the network 5 via the communication line 11. Thereby, the e-mail transmission process in the e-mail information encryption apparatus 3 is completed.

  On the other hand, returning to step S202, if the security importance of the electronic document attached to the e-mail is not “Low” which is a low level (No at step S202), that is, the e-mail attached to the e-mail. If the security importance level of the document is “Normal”, “High”, and “No importance level information is specified”, the encryption processing unit 103 extracts the attached electronic document (step S204). The document is encrypted (step S205).

  At this time, the encryption processing unit 103 automatically generates a password for decrypting the encrypted electronic document (step S205). The generated password moves in the electronic mail information encryption apparatus 3 together with the electronic mail and the encrypted electronic document until the electronic document encrypted in step S401, which will be described later, is received by the control unit 102. Therefore, the description of the password transfer is omitted until the description of step S401 described later.

  In the example described here, there is no difference in the encryption algorithm depending on the contents of the control information. However, if the encryption processing unit 103 controls the type of the encryption algorithm based on the control information, the control is performed. It is possible to perform encryption using encryption algorithms having different strengths according to information.

  Next, the encryption processing unit 103 determines whether or not registration (upload) of the encrypted electronic document to the file server function unit 106 is instructed in the control information given to the e-mail (step). S206).

  When the registration (upload) of the encrypted electronic document to the file server function unit 106 is not instructed (No at Step S206), the encryption processing unit 103 controls the electronic mail together with the encrypted electronic document. 102 (step S207).

  On the other hand, when the registration (upload) of the encrypted electronic document to the file server function unit 106 is instructed (Yes in step S206), the encryption processing unit 103 transmits the encrypted electronic document to the file server function unit. The URL information for accessing the encrypted electronic document registered in the file server 106 and registered in the file server function unit 106 is acquired from the file server function unit 106 (step S208). The acquired URL information moves in the e-mail information encryption apparatus 3 together with the e-mail and the encrypted electronic document until the control unit 102 receives the encrypted electronic document in step S401 described later. Therefore, the description of the movement of URL information is omitted until the description of step S401 described later.

  Here, when the registration (upload) of the encrypted electronic document to the file server function unit 106 is instructed, for example, the security importance of the electronic document attached to the e-mail is high. It can be the case. That is, when the electronic document has a high importance in security, the encrypted electronic document is registered in the file server function unit 106, and the e-mail recipient accesses the file server function unit 106 so that the electronic document is stored. Try to see. Thereby, information protection of an electronic document can be performed at a higher level.

  After registering (uploading) the encrypted electronic document in the file server function unit 106, the encryption processing unit 103 transmits the encrypted electronic document and electronic mail to the control unit 102 (step S207).

  When the control unit 102 receives the encrypted electronic document and the e-mail transmitted from the encryption processing unit 103, the control unit 102 transmits the encrypted electronic document and the e-mail to the history information management unit 104. To do.

  Next, when the history information management unit 104 receives the encrypted electronic document and the electronic mail transmitted from the control unit 102 (step S301), information related to the transmission / reception of the electronic mail is given to the electronic mail. Obtained from the control information (step S302) and registered in the database 105 as history information (step S303).

  When only the <File Name> element and the <Control Level> element are added to the email as control information, the history information management unit 104 sends information related to transmission / reception of email other than these two emails. And is registered in the database 105.

  FIG. 5 is a diagram illustrating an example of history information registered in the database 105 by the history information management unit 104 for each security importance level of the electronic document. In FIG. 5, “◯” indicates information that the history information management unit 104 registers in the database 105, and “−” indicates information that the history information management unit 104 does not register in the database 105.

  After registering the history information in the database 105, the history information management unit 104 transmits the encrypted electronic document and the electronic mail to the control unit 102 (step S304).

  When the control unit 102 receives the encrypted electronic document and the e-mail transmitted from the history information management unit 104 (step S401), the control unit 102 registers (uploads) the encrypted electronic document in the file server function unit 106. ) Is confirmed (step S402). In step S401, the control unit 102 also receives the password described above. When URL information is also transmitted, the control unit 102 receives the URL information together.

  If the encrypted electronic document is not registered (uploaded) in the file server function unit 106 (No in step S402), the control unit 102 attaches the encrypted electronic document to the email (step S402). In step S403, the electronic mail is transmitted to the mail server function unit 101 for transmission to the sender (step S404).

  Next, based on the control information, the control unit 102 creates a history information e-mail with the history information registered in the database 105 (step S405), and sends the history information e-mail to be sent to the sender. The data is transmitted to the server function unit 101 (step S406).

  Next, since the control unit 102 has received the password for decrypting the encrypted electronic document, the control unit 102 creates a password email describing the password (step S407) and transmits the password to the sender. The password e-mail is transmitted to the mail server function unit 101 (step S408).

  The mail server function unit 101 transmits an electronic mail attached with an encrypted electronic document, a history information electronic mail, and a password electronic mail to the network 5 via the communication line 11. Thereby, the e-mail transmission process in the e-mail information encryption device 3 is completed.

  Returning to Step S402, if the encrypted electronic document is registered (uploaded) in the file server function unit 106 (Yes in Step S402), the control unit 102 adds URL information to the email (Step S402). In step S409, the electronic mail is transmitted to the mail server function unit 101 for transmission to the sender (step S404). Thereafter, after performing the processing of the above-described steps S404 to S408, the mail server function unit 101 sends the email with the URL information, the history information email, and the password email via the communication line 11. To the network 5. Thereby, the e-mail transmission process in the e-mail information encryption apparatus 3 is completed.

  In addition, when information of “no importance level information is specified” is specified in the control information as the importance level information indicating the security importance level of the electronic document attached to the e-mail, the above-described history information electronic Does not create or send mail. FIG. 6 is a diagram illustrating an example of main processing performed by the electronic mail information encryption device 3 for each security importance level of the electronic document.

  In FIG. 6, “◯” indicates a process performed by the electronic mail information encryption apparatus 3, and “−” indicates a process not performed by the electronic mail information encryption apparatus 3. In FIG. 6, “encryption” indicates the encryption of the electronic document, “record history” indicates the record of history information in the history information database 105, and “send history” indicates the transmission of history information e-mail. ing.

  As shown in FIG. 6, when information “no importance level information is specified” is specified as the importance level information in the control information, the electronic document is encrypted and the history information is recorded in the database 105. No history information e-mail is sent. Further, when “Low” information is designated as the importance information in the control information, all of the encryption of the electronic document, the recording of the history information in the database 105, and the transmission of the history information e-mail are performed. Absent.

  The e-mail transmitted from the mail server function unit 101 is received by the e-mail receiving terminal device 7 of a predetermined destination via the communication line 11, the network 5, and the communication line 13.

  When the e-mail receiving terminal device 7 receives an e-mail attached with an encrypted electronic document and a password e-mail, the user (recipient) uses the password described in the password e-mail. The encrypted electronic document attached to the e-mail can be decrypted and the contents of the electronic document can be viewed.

  When the e-mail receiving terminal device 7 receives the e-mail with the URL information and the password e-mail, the user (recipient) uses the URL information given to the e-mail to 5 and the authentication server function unit 107 of the e-mail information encryption device 3 are accessed to the file server function unit 106 of the e-mail information encryption device 3. Then, the encrypted electronic document registered in the file server function unit 106 is decrypted using the password described in the password electronic mail, and the contents of the electronic document can be viewed.

  When the user (recipient) accesses the file server function unit 106 from the e-mail receiving terminal device 7, information on the accessed date and time is transmitted from the file server function unit 106 to the control unit 102. The control unit 102 transmits this information to the history information management unit 104, and the history information management unit 104 registers this information in the database 105 (see FIG. 5). That is, when a user (recipient) accesses the file server function unit 106 from the electronic mail receiving terminal device 7, information on the accessed date and time is automatically registered in the database 105. And based on the control information of the email transmitted by the user (sender), the history information email can be transmitted at a predetermined timing. Thereby, the user (sender) can confirm whether or not the receiver has received the electronic document.

  As described above, in the electronic mail communication system according to the present embodiment, the electronic mail information encryption apparatus 3 automatically encrypts the electronic document. As a result, even when an electronic mail attached with an electronic document is transmitted from a terminal device that does not have the function of encrypting the electronic document, the electronic document is automatically encrypted and attached to the electronic mail. Document information can be protected.

  Further, in the electronic mail communication system according to the present embodiment, even when the importance information included in the control information is “no importance information specified”, the electronic document is automatically encrypted, so that the user Even when the (sender) forgets the encryption processing instruction, that is, the importance information selection instruction, the electronic document can be automatically encrypted to protect the electronic document information attached to the e-mail. it can.

  In the electronic mail communication system according to the present embodiment, when the security importance (importance information) of the electronic document attached to the electronic mail is low, the electronic document is automatically encrypted. Since this is not performed, by specifying “Low” as the importance information included in the control information, an electronic document that does not need to be encrypted can be transmitted without being encrypted. In this case, the receiver side does not need to compose the electronic document attached to the received electronic mail, and the load on the receiver side does not increase.

  In the electronic mail communication system according to the present embodiment, the encrypted electronic document is transmitted to the recipient in accordance with the security importance (importance information) of the electronic document attached to the electronic mail. And a mode in which a URL in which an encrypted electronic document is registered is transmitted to a recipient. This eliminates the need for the recipient to access and view the entire URL of the encrypted electronic document.

  Further, in the electronic mail communication system according to the present embodiment, when a user (recipient) accesses the file server function unit 106 from the electronic mail receiving terminal device 7, information on the accessed date and time is automatically stored in the database 105. Registered. And, in the electronic mail communication system according to the present embodiment, based on the control information of the electronic mail transmitted by the user (sender), a function for transmitting history information electronic mail at a predetermined timing is provided. The user (sender) can confirm whether or not the receiver has received the electronic document.

  A technique for storing a transmission history and providing the transmission history to a sender has been proposed (see, for example, JP-A-2002-269012). In this technique, the sender is notified of all transmission histories, and the sender needs to confirm all of these transmission histories, which greatly increases the workload of the sender. There is. However, in the electronic mail communication system according to the present embodiment, it is possible to selectively use the case where transmission history information is sent to the sender and the case where transmission history information is not sent to the sender. Thereby, the work load of the sender can be reduced.

  In the electronic mail communication system according to the present embodiment, transmission history information is transmitted to the sender according to the security importance (importance information) of the electronic document attached to the transmitted electronic mail. Therefore, since transmission history information is not transmitted for all transmitted e-mails, the user (sender) only needs to check the transmission history for e-mails whose importance information has a predetermined rank. It is possible to reduce the work load of the sender.

  As described above, the electronic mail communication system according to the present invention is useful in an environment where a terminal device that does not have a function of encrypting an electronic document exists.

It is a figure which shows schematic structure of the electronic mail communication system concerning one embodiment of this invention. It is a flowchart for demonstrating the processing flow in the electronic mail information encryption apparatus concerning embodiment of this invention. It is a flowchart for demonstrating the processing flow in the electronic mail information encryption apparatus concerning embodiment of this invention. It is a flowchart for demonstrating the processing flow in the electronic mail information encryption apparatus concerning embodiment of this invention. It is a flowchart for demonstrating the processing flow in the electronic mail information encryption apparatus concerning embodiment of this invention. It is a figure which shows an example of the email preparation instruction | indication screen of the email transmission terminal device concerning embodiment of this invention. It is a figure which shows an example of the control information provided to the email which a user (sender) transmits. It is a figure which shows an example of the log | history information which the log | history information management part of the electronic mail transmission terminal device concerning embodiment of this invention registers into a database for every importance on the security of an electronic document. It is a figure which shows an example of the main processes performed with the electronic mail information encryption apparatus concerning embodiment of this invention for every importance on the security of an electronic document.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 E-mail transmission terminal device 3 E-mail information encryption device 5 Network 7 E-mail reception terminal device 9 Communication line 11 Communication line 13 Communication line 101 Mail server function part 102 Control part 103 Encryption processing part 104 History information management part 105 Database 106 File Server Function Unit 107 Authentication Server Function Unit

Claims (8)

An e-mail sending terminal device for creating an e-mail attached with an electronic document and sending control information related to encryption control of the attached electronic document to the e-mail;
Connected to the e-mail transmission terminal device;
A mail server function unit having a mail server function for the e-mail;
An encryption processing unit for automatically encrypting the electronic document attached to the electronic mail transmitted from the mail server function unit based on the control information given to the electronic mail;
A history information management unit for managing history information related to transmission and reception of the electronic mail in which the electronic document is encrypted;
A database for storing the history information;
A control unit for attaching the encrypted electronic document to the electronic mail and transmitting the electronic document to the mail server function unit, and for controlling the entire apparatus relating to automatic encryption of information of the electronic document attached to the electronic mail When,
An e-mail information encryption device comprising:
An e-mail receiving terminal device connected to the e-mail information encryption device via a network and receiving an e-mail attached with an electronic document subjected to automatic encryption processing in the e-mail information encryption device;
An e-mail communication system, comprising: An e-mail that creates an e-mail attached with an electronic document and is connected to an e-mail transmission terminal device that sends control information related to the control of encryption of the electronic document to the e-mail and performs e-mail communication An electronic mail information encryption device constituting a communication system,
A mail server function unit having a mail server function for the e-mail transmitted from the e-mail transmission terminal device;
An encryption processing unit for automatically encrypting the electronic document attached to the electronic mail transmitted from the mail server function unit based on the control information given to the electronic mail;
A history information management unit for managing history information related to transmission and reception of the electronic mail in which the electronic document is encrypted;
A database for storing the history information;
A control unit for attaching the encrypted electronic document to the electronic mail and transmitting the electronic document to the mail server function unit, and for controlling the entire apparatus relating to automatic encryption of information of the electronic document attached to the electronic mail When,
An electronic mail information encryption device comprising: The electronic mail information encryption apparatus according to claim 2, wherein the control information includes information on the importance of security of the attached electronic document. The electronic document having been encrypted based on the control information is registered so as to be accessible from an external terminal, and further includes a file server function unit that generates registration position information of the registered electronic document. Item 3. The electronic mail information encryption device according to Item 2. 3. The electronic mail information encryption according to claim 2, wherein history information relating to transmission / reception of the electronic mail in which the electronic document is encrypted is attached to the electronic mail and automatically transmitted to the electronic mail transmitting terminal device. Device. The electronic mail information encryption apparatus according to claim 2, wherein the electronic document can be automatically encrypted based on the control information. An e-mail transmission terminal device constituting an e-mail communication system connected to an e-mail information encryption device that performs automatic encryption of an electronic document attached to an e-mail, and performs e-mail communication,
An e-mail transmission terminal apparatus that creates an e-mail attached with the electronic document, and sends control information related to encryption control of the attached electronic document to the e-mail. The electronic mail transmitting terminal device according to claim 7, wherein the control information includes information on the importance of security of the attached electronic document.

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