JPH1188410A - Method and device for transferring electronic mail and recording medium for recording the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to perform access to a mail server 100 with an internal network from an internet. SOLUTION: A relay server 100 being accessable to the mail server 100 with a gateway for executing access control to the internal network is provided in the internet, the cipher key of a usage terminal 120 is previously inputted to the mail server 100, the transfer condition of the electronic mail is also previously given, the mail server 100 extracts the electronic mail 107 of a storing part 101 at the time of the transfer condition, the extracted electronic mail 107 is ciphered(103) so as to be transferred to the relay server 100 and it is stored in the storing part 111. The terminal 120 transmits authenticating information with the server 100 and an electronic mail reading request to the server 100 and the relay server 100 extracts the corresponding electronic mail(113) so as to transfer it to the terminal 120. The terminal 120 decodes the electronic mail(121) and displays it in a display part 122.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic mail storage server on an internal network and a user terminal used by a user on the external network via a gateway for controlling access from an external network. The present invention relates to an electronic mail transfer method for transferring mail, an apparatus used for the method, and a program recording medium.

[0002]

2. Description of the Related Art Conventionally, e-mail stored in a server is browsed within a secure network such as a LAN, or between a server in which the e-mail is stored and a user's terminal. By holding the line, the e-mail is transferred and viewed while security is ensured.

[0003]

In the prior art, a mail server in which electronic mail on an internal network is stored from an external network such as a computer network (for example, the Internet), which is not secured, via a gateway. It was difficult to access and obtain the e-mail.

[0004] Further, when transferring an electronic mail, transferring and storing an electronic mail with high confidentiality to a network where security is not secured has a problem in terms of security such as eavesdropping. Furthermore, when transferring e-mail, if data created by an application and the like attached to the e-mail are included, the file size becomes very large, the transfer is overloaded, and the storage capacity increases. there were.

[0005] It has been difficult to send an e-mail under the name of a user from a mail server having an account unique to the user on the road. Therefore, an object of the present invention is to (1) allow a user (user) to browse from anywhere, (2) securely transfer an e-mail while maintaining confidentiality, and (3) use an electronic mail. Reduce the load on mail transfer and storage, and on the go,
(4) An object of the present invention is to provide an e-mail transfer method for transmitting an e-mail under the name of a user from a mail server having a user-specific account.

[0006]

According to the present invention, a user (user) who transfers an e-mail requests an e-mail transfer, and copies the e-mail stored in a mail server on an internal network. Encrypting the duplicated e-mail using an encryption key input in advance by the user, and transmitting the encrypted e-mail to a relay server designated by the user on an external network that is not secured. Automatically, the user obtains the encrypted e-mail from the relay server on the external network, decrypts the encrypted e-mail, and browses the encrypted e-mail. In this way, the user can browse the e-mail stored in the mail server on the internal network from anywhere. In addition, confidentiality can be maintained.

Further, according to the present invention, the user who transfers the e-mail requests the transfer of the e-mail, and copies the e-mail from the mail server on the internal network where the e-mail is stored. Using the encryption key input in advance, encrypts only the body of the e-mail, transfers the encrypted body and header information in plain text to the relay server, and the user The encrypted electronic mail is obtained from the relay server on the network, and the encrypted electronic mail is decrypted and viewed. In this way, the user can know the header information of the e-mail in the mail server from anywhere without decoding. The text can be kept confidential.

According to the present invention, the user who transfers the electronic mail requests the transfer of the electronic mail, copies only the header information of the electronic mail stored in the mail server on the internal network, and encrypts the user. When the request is made, the header information of the e-mail is encrypted using the encryption key input in advance by the user and transferred to the relay server, and when the user does not make the encryption request, the header information is The data is transferred to the relay server in plain text, and the user acquires the transferred e-mail from the relay server on the external network, and decrypts and views the e-mail if the e-mail is encrypted. In this way, it is possible to know what information is stored in the mail server from the header information, and since only the header information is transferred to the relay server, the load is large and the storage unit capacity is small. Is fine.

According to the present invention, a user who views an electronic mail transfers the electronic mail to a server on the internal network through the relay server based on header information of the electronic mail stored in the relay server. Request, and after performing authentication with the server on the internal network where the e-mail is stored, duplicates the e-mail from the server on the internal network where the e-mail is stored, and encrypts the user. Request, the user encrypts the e-mail using the encryption key input in advance and transfers it to the relay server. If the user does not request encryption, the e-mail is Forwarded to the relay server as it is, the user obtains the forwarded e-mail from the relay server on the external network, If the e-mail is encrypted and decrypted, to browse.

According to the present invention, a user who sends an e-mail encrypts the e-mail to be sent, transmits authentication information for the mail server and the encrypted e-mail to the relay server, and the relay server Sent from the relay server to the mail server, the mail server performs user authentication, then decrypts using the decryption key input by the user in advance,
Sending the decrypted email.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In the following, a user who transfers an e-mail requests an e-mail transfer, so that a user on an internal network can use an encryption key input by the user in advance. After encrypting the stored e-mail, it is automatically transferred to the relay server on the external network, and the user
It accesses the relay server, acquires, decrypts, and browses e-mail. First Embodiment A first embodiment of the present invention will be described.

FIG. 1 shows a schematic functional configuration of an electronic mail transfer apparatus to which the present invention is applied. The mail server 100 is provided on an internal network, and has an electronic mail storage unit 101.
, The e-mail extraction unit 102, and the e-mail encryption unit 1
03, the e-mail transfer unit 104, and the user authentication unit 10
5 and an e-mail decryption unit 106. In the present invention, the relay server 110 is provided on an external network where security is not ensured, such as the Internet,
The user terminal 120 sends and receives e-mails in the mail server 100 via the relay server 110. The relay server 110 includes an e-mail storage unit 111, an e-mail extraction unit 113, an e-mail transfer unit 114, and an information transfer unit 1.
15 and a user authentication unit 112, and stores an encrypted electronic mail 116, electronic mail header information 117, and an electronic mail 118 in an electronic mail storage unit 111.

The use terminal 120 is connected to the e-mail decryption unit 12.
1, an e-mail display unit 122, and an e-mail creation unit 1
23, an e-mail encryption unit 124, and an information transfer unit 12
5 and an authentication information generation unit 126. As shown in FIG.
From the relay server 110 via the Internet 140
However, it is not possible to access the mail server 100 and directly obtain the e-mail 107 stored in the e-mail storage unit 101.

The relay server 110 is connected to the Internet 13
The e-mail can be transmitted to the mail server 100 via the “0”. The mail server 100 can transfer the electronic mail 107 in the electronic mail storage unit 101 to the relay server 110 via the Internet 130. At this time, the mail server 100 and the relay server 11
The communication protocol between 0 is not limited. Mail server 10
Normal access from the external network to the internal network containing 0 is blocked by the gateway, but only electronic mail can be accessed.

In the following, the mail server 100 encrypts the e-mail 107 using the encryption key 108 input in advance by the user who transfers the e-mail, and automatically transfers the e-mail 107 to the relay server 110. Is used terminal 120
Access the relay server 110 from the
A description will be given of a processing procedure in which authentication is performed with 0, an encrypted e-mail 116 is obtained, decrypted by the use terminal 120, and browsed.

First, a user who transfers the e-mail 107 directly starts an e-mail transfer program on the mail server 100 in advance, and sends the encryption key 108 to the mail server 1.
Input within 00. At this time, the transfer conditions of the e-mail 107 to be transferred can be input. The mail server 100, based on the conditions entered by the user,
For example, the transfer of the e-mail is started every time a new e-mail is received or at a predetermined time interval.

As shown in FIG. 2, the mail server 100
Is stored in the e-mail storage unit 10 by the e-mail extraction unit 102.
The e-mail 107 is extracted from 1 (201), and when there is an encryption request from the user (202), the encryption key 108 is obtained (203), and the e-mail is encrypted by the encryption unit 103. (204), the transfer of the encrypted electronic mail 116 to the relay server 110 is performed by the transfer unit 104 (205). In relay server 110, the encrypted electronic mail 116 is stored in electronic mail storage section 111. If there is no encryption request from the user (202), the extracted electronic mail 107 is immediately transferred to the relay server 110 (205).

As shown in FIG. 3, when the relay server 110 requests browsing of the electronic mail in the relay server 110 from the user (301), the relay server 110 uses the authentication information received from the user to use the user authentication unit 112. Performs a user authentication process (302). If the authentication information is indicated to be correct, the e-mail extraction unit 113 extracts an e-mail addressed to the user (303), and the e-mail transfer unit 114 extracts the encrypted e-mail to the user terminal 120. The mail 116 is transferred (304).

As shown in FIG. 4, in the use terminal 120,
When the user who browses the e-mail inputs the browsing request, the user accesses the relay server 110 and makes a browsing request for the e-mail (401). The user generates authentication information with the relay server in the authentication information generation unit 126 (40).
2), the generated authentication information is transferred from the information transfer unit 125 to the relay server 110. When the use terminal 120 obtains the e-mail (403), if the transferred e-mail is encrypted, the e-mail decryption unit 121
Decryption processing (404), and the e-mail display unit 12
In step 2, an electronic mail is displayed (405).

In the first embodiment, if the e-mail is not encrypted, the user who views the e-mail
Obviously, the user can browse the plain text e-mail 118 or the e-mail header information 117. Second Embodiment In the following, a user who views an e-mail is set in advance so that header information of the e-mail is transferred, and a user terminal relays to a mail server on an internal network using the header information. A request is made to transfer the body of the e-mail to the server. After the e-mail is transferred from the mail server to the relay server, the relay server is accessed, the transferred e-mail is obtained and viewed. Second Embodiment A second embodiment of the present invention will be described.

The schematic functional configuration of an electronic mail transfer device to which the second embodiment is applied is as shown in FIG. 1 as in the first embodiment. Briefly describing the second embodiment, a user who is set to transfer the header information of an e-mail extracts the header information 117 of the e-mail from the relay server 110 from the user terminal 120, browses, and then browses the e-mail to be viewed. If there is a text, the authentication information generation unit 126 generates authentication information with the mail server, transmits the generated authentication information to the relay server 110, and the relay server 110 transmits the transferred authentication information to a mail on the internal network. The mail server 100 extracts the e-mail specified by the user in the e-mail extraction unit 102, and uses the encryption key 108 input in advance by the user in the e-mail encryption unit 103. E-mail transfer unit 104
To the relay server 110, the user generates authentication information with the relay server in the authentication information generation unit 126,
In the information transfer unit 125, the generated authentication information is transmitted to the relay server 110. The relay server 110 extracts the encrypted electronic mail 116 in the electronic mail extraction unit 113, and sends it to the electronic mail transfer unit 114. Then, the encrypted e-mail 116 is transferred to the use terminal 120, the e-mail decryption unit 121 decrypts the encrypted e-mail, and the e-mail display unit 122 displays the e-mail text. And the user browses the email body.
This will be specifically described below.

As shown in FIG. 5A, the mail server 100
In the e-mail storage unit 101, the e-mail 1
07 (501), and the extracted e-mail 1
E-mail transfer unit 10 by taking out only the header information 07
In 4, the data is transferred to the relay server 110 (502).
As shown in FIG. 5B, the user who views the e-mail
In the usage terminal 120, the authentication information generation unit 126 generates authentication information with the relay server 110 (503). When the user is authenticated by the relay server 110, the user sends the e-mail header from the relay server 110 to the usage terminal 120. Information is acquired (504), and the e-mail display unit 121 is obtained.
, The electronic mail header information is displayed (505).
When the user makes a request for browsing the electronic mail text based on the displayed header information, the authentication information generation unit 1 generates the authentication information with the mail server 100 as shown in FIG.
26 (406), and transmits to the relay server 100 the information of the e-mail requesting transmission and transfer of the generated authentication information to the relay server 100 (407). Do.

As shown in FIG. 3, the relay server 110
If the received information is not an e-mail browsing request to the relay server 110 (301), the received e-mail text browsing request to the mail server 100, the information designating the e-mail to be transferred, and the authentication information with the mail server are sent to the e-mail. In order to transmit the data to the server 100, the information transfer unit 115 performs data conversion (305), and transmits the received information to the mail server 100 (306).

For example, the user terminal 120 and the relay server 11
0 is performed by HTTP, and the communication between the relay server 110 and the mail server 100 is performed by SMTP, the data sent from the use terminal 120 is H
Since the data is based on TML, the information transfer unit 115 converts the data into data that can be handled by SMTP. As shown in FIG. 5, when the mail server 100 receives the data-converted e-mail transfer request, the user authentication unit 105 performs an authentication process using the simultaneously transmitted authentication data (506). If the authentication is successful (507), information about which e-mail is to be transferred is passed to the e-mail extraction unit 102.

Based on the information sent from the user,
The processing procedure for extracting the e-mail 107 and transmitting it to the relay server 110 is the same as in the first embodiment. Further, a processing procedure in which a user who browses the electronic mail accesses the relay server 110 and browses the text of the electronic mail 116 is described in the first embodiment.
Is the same as Embodiment 3 A user who wants to send an e-mail
0, an e-mail is created, the e-mail is encrypted, and the encrypted e-mail is
0, the relay server 110 sends the encrypted e-mail to the mail server 100 on the internal network, and the mail server 100 decrypts the encrypted e-mail, Send e-mail. Embodiment 3 will be described below.

The schematic functional configuration of the electronic mail transfer apparatus to which the third embodiment is applied is as shown in FIG. This embodiment 3 will be described briefly. A user who wants to send an e-mail,
E-mail information including a text, a title, and a destination address is created, the e-mail information is encrypted in an e-mail encryption unit 124, and authentication information with the mail server 100 is generated in an authentication information generation unit 126. Then, the information transmitting unit 125 transmits the encrypted e-mail information and the generated authentication information of the mail server to the relay server 110, and
In the information transfer unit 115, the encrypted electronic mail information and the authentication information of the mail server are transferred to the mail server 100, and the mail server 100
A user authentication unit 105 performs user authentication based on the authentication information, and an e-mail decryption unit 106 decrypts the encrypted e-mail information based on a decryption key previously input by the user, and Extract body, email title and email destination address,
The e-mail transfer unit 104 transmits the e-mail text and the e-mail title to the e-mail transmission destination address. Hereinafter, the processing procedure will be described.

As shown in FIG. 6, a user who sends an e-mail creates an e-mail information including an e-mail text, a title, and a destination address in an e-mail creating section 123 at a use terminal 120. (60
1) The encryption of the e-mail information is performed by the encryption unit 124 using the encryption key input by the user (602), and the authentication information with the mail server 100 is generated by the authentication information generation unit 126 (603). ), And transmits the mail server authentication information generated by the authentication information generation unit 126 and the encrypted electronic mail information to the relay server 110 (604).

As shown in FIG. 3, the relay server 110
Indicates that the information received from the usage terminal 120 is the relay server 1
If it is not the electronic mail browsing request of No. 10, the received encrypted electronic mail information and the authentication information of the mail server are subjected to data conversion for communication protocol conversion (305) and transferred to the mail server 100 (305). 30
6). At this time, between the relay server 110 and the use terminal 120,
The communication protocol between the mail server 100 and the relay server 110 does not matter. Further, the relay server 110 only changes the communication protocol and does not change the content of the data received from the use terminal 120 at all.

As shown in FIG. 7, the mail server 100
Performs authentication processing in the user authentication unit 105 based on the received authentication information (701), and if the authentication information is incorrect (702), performs error processing and ends the processing (703). If the authentication information is correct (702), the e-mail information received from the relay server 120 is decrypted using the decryption key 106 input by the user in advance.
0 (704), and extracts e-mail information including the main body of the e-mail, the title of the e-mail, and the destination address of the e-mail (705).
The transfer unit 104 transmits the text of the e-mail and the title of the e-mail from the user's account to the destination address of the e-mail (706).

[0030]

The effects obtained by the electronic mail transfer service transfer method and the apparatus for implementing the present invention are as follows. In an environment where access from the external network is restricted by a gateway, etc., the user automatically transfers e-mail stored in the internal network to a relay server on the external network when the user requests it. By accessing the relay server on the external network, you can browse e-mail at any time.

By encrypting the electronic mail to be transferred using the encryption key input by the user in advance, the electronic mail can be safely stored in the relay server on the external network. By transferring only the header information of the e-mail, only the necessary e-mail can be viewed,
Further, the storage capacity of electronic mail in the relay server can be suppressed.

By sending an e-mail under the user's name from a mail server at a destination, responsibility for the contents of the e-mail can be clarified. By decrypting the transmitted e-mail in the mail server, the confidentiality of the contents of the e-mail can be maintained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic functional configuration of an electronic mail transfer device to which the present invention is applied.

FIG. 2 is a flowchart showing a processing procedure of electronic mail automatic transfer in the mail server 100;

FIG. 3 is a flowchart showing an e-mail transfer process in response to a browsing request from a user and a process procedure of transferring necessary information of a mail from a user terminal in the relay server 110.

FIG. 4 is a flowchart showing a processing procedure of an electronic mail browsing request to the relay server 110 and a processing procedure of an electronic mail transfer request to the mail server 100 in the user's use terminal 120;

5A is a flowchart illustrating a header information transfer procedure in a mail server, FIG. 5B is a flowchart illustrating header information acquisition processing in a use terminal, and FIG. 5C is a flowchart illustrating an authentication processing procedure in a mail server.

FIG. 6 is an exemplary flowchart showing the procedure of an electronic mail transmission process performed by a user's terminal.

FIG. 7 is an exemplary flowchart showing an e-mail transmission processing procedure in the mail server.

Claims (13)

[Claims] An electronic mail transfer method between a mail server on an internal network and a user's terminal on an external network performed via a gateway for controlling access from the external network to the internal network. A relay server is provided, the electronic mail stored in the mail server on the internal network is duplicated by a request from a user terminal of a user who browses the electronic mail via the relay server, and the electronic mail is input in advance by the user. Encrypting the body of the duplicated e-mail using an encryption key, automatically transferring the encrypted e-mail to a relay server on the external network designated by the user, After performing authentication with the relay server, the encrypted Get the email to decrypt the encrypted e-mail, e-mail transfer method for viewing. 2. The electronic mail transfer method according to claim 1, wherein the encryption in the mail server is performed not only for the text of the electronic mail but also for header information of the electronic mail. 3. A method for transferring e-mail between a mail server on an internal network, which controls access from an external network to an internal network via a gateway, and a user terminal of a user on the external network, the method comprising: Providing a relay server, copying only the header information of the e-mail from the mail server on the internal network where the e-mail is stored, transferring only the header information to the relay server, and using the user terminal of the user An electronic mail transfer method for acquiring the header information from the relay server after performing authentication with the relay server, and browsing the header information. 4. The mail server transmits the header information,
4. The electronic device according to claim 3, wherein the user encrypts the encrypted header information using an encryption key input in advance and transfers the encrypted header information to the relay server, and the user terminal decrypts and browses the encrypted header information. Email forwarding method. 5. A method according to claim 1, wherein said user terminal uses header information based on header information.
Requesting transfer of e-mail to a server on the internal network through the relay server, performing authentication with a mail server storing e-mail on the internal network, and storing e-mail on the internal network From the mail server being copied, the electronic mail is copied, and when the user makes a request for encryption of the electronic mail, the electronic mail is encrypted by using an encryption key input in advance by the user, and the electronic mail is encrypted. 5. The electronic mail transfer method according to claim 3, wherein the electronic mail is transferred to the relay server, and if the user does not request the encryption of the electronic mail, the electronic mail is transferred to the relay server in plain text. 6. A method for transferring e-mail between a mail server on an internal network, which performs access control from an external network to an internal network via a gateway, and a user's terminal on the external network, the method comprising: Providing a relay server, a user who sends an e-mail creates an e-mail by using the user terminal, encrypts the created e-mail, transmits the encrypted e-mail to the relay server, the relay Sending the encrypted e-mail from a server to the mail server, the mail server decrypts the received encrypted e-mail using a decryption key input in advance by the user, and E-mail forwarding method to send e-mail. 7. It is provided on an external network, and can be connected to a user terminal on the external network,
A relay server that can be connected to a mail server capable of storing e-mail on the internal network via a gateway that performs access control, wherein the relay server stores the e-mail transferred from the mail server and the header information of the e-mail. A mail storage unit, a user authentication unit that verifies the authentication information received from the use terminal, and a unit that extracts, from the storage unit, request information related to the e-mail received together with the authentication information when the user authentication unit passes the verification. Means for transferring the information on the extracted e-mail to the use terminal; and means for converting the browsing request information received from the use terminal to the mail server and transferring the information to the mail server. Relay server. 8. It is provided on an external network, and can be connected to a user terminal on the external network.
And a recording medium storing a program for causing a computer to execute processing of a relay server connectable via a gateway that performs access control to a mail server capable of storing electronic mail on an internal network; Storing the information related to the received e-mail in the storage unit; verifying the authentication information received from the use terminal; extracting the information related to the e-mail received along with the authentication information from the storage unit if the verification is passed; And a step of transferring the information on the extracted e-mail to the use terminal, and a step of receiving the information from the use terminal to the mail server and converting the data and transferring the data to the mail server. Recording medium on which is recorded. 9. A mail server provided on an external network and storing e-mail on the internal network,
A recording medium recording a program for executing, by a computer, a process of a terminal used by a user who transmits / receives information relating to an e-mail to / from the mail server via a relay server connectable via a gateway that performs access control. Generating authentication information with the relay server; transmitting the generated authentication information and request information on the electronic mail to the relay server; and displaying information on the electronic mail transferred from the relay server. And a display medium for storing a program having the following. 10. The recording medium according to claim 9, wherein said program includes a step of decrypting information relating to the electronic mail transferred from said relay server and passing it to said display step. 11. The electronic mail according to claim 9, wherein the information about the electronic mail is one of the electronic mail itself, header information of the electronic mail, and a body of the electronic mail.
Or the recording medium according to 10. 12. A process for generating authentication information with the mail server, and transmitting the authentication information with the mail server and a request for browsing the email itself or its header information or text to the relay server, 9. The program according to claim 9, wherein the program has a step of requesting transfer to a computer.
2. The recording medium according to claim 1. 13. A process for creating an email, a process for encrypting the generated email, a process for generating authentication information for the mail server, a process for encrypting the email and the mail server. 13. The recording medium according to claim 9, wherein the program has a step of transmitting authentication information to the relay server and requesting the mail server to transfer the authentication information.