JP4728902B2 - Secure mail distribution system, secure mail distribution apparatus, secure mail distribution method, and program - Google Patents

Description

  The present invention relates to an e-mail distribution system, an e-mail distribution apparatus, an e-mail distribution method, and a program, and in particular, a secure mail distribution system, a secure mail distribution apparatus, a secure mail distribution method, and a program using a public key cryptosystem, and Regarding the program.

  In recent years when electronic commerce via the Internet is becoming widespread, important data is exchanged by e-mail with security. As security measures for electronic mail, information leakage, falsification, and spoofing prevention using public key cryptography (PKI = Public Key Infrastructure) is generally used.

  Such a security measure by PKI has a problem that its setting is complicated and it is difficult for general users to use it frequently. Therefore, an electronic mail system is known in which a mail server has security functions such as encryption of electronic mail using PKI, electronic signature, and attachment of an electronic certificate.

  For example, in Patent Document 1, in a system in which a user terminal, an e-mail server, and a certificate authority are connected via an Internet network, when an e-mail is transmitted, the e-mail server encrypts e-mail using PKI, An electronic signature and an electronic certificate are added, and when an email is received, the mail server decrypts the email, confirms the electronic certificate, and confirms the message using the electronic signature, thereby preventing information leakage. A method for detecting tampering and impersonation is disclosed.

JP 2003-198632 A

  When a company distributes a large amount of advertising mail to a large number of destination users, only a part of the text is transmitted so as to be suitable for each destination user. Further, such advertisement mail includes important data such as payment information, and the advertisement mail is used for electronic commerce. In this case, a trusted third-party organization proves to the user who is the destination of the advertising email that the content of the advertising email has not been altered and that the company that sent the advertising email is a socially trustworthy company There is a need to.

  For example, when a business operator handling important information such as payment information sends an advertisement e-mail notifying the customer of guidance to the management page, a malicious party impersonates a business operator handling payment information, and an actual payment site In order to prevent phishing scams that induce email recipients to a site that is very similar to that and collect information such as credit card numbers, it is required to prove the validity of the content of the advertisement email and the reliability of the sender.

  However, the above-described conventional electronic mail system has the following problems.

  The first problem is that when advertising mail that is distributed in large quantities as described above is transmitted, the load on the user terminal or mail server that is the transmission source increases. This is because, in the above-described conventional electronic mail system, the transmission source user terminal creates a large amount of emails with different body contents and transmits them individually to the mail server, and the mail server receives the individual emails received from the transmission source user terminal. This is because it is necessary to search for a private key and an electronic certificate corresponding to the transmission source user, create an electronic signature, and attach it to the mail text together with the electronic certificate.

  A second problem is that the electronic certificate attached by the mail server may be issued by a third party other than a trusted third party. This is because in the above-described conventional e-mail system, an electronic certificate issued by a third party other than a trusted third party can be attached because an electronic certificate obtained by the sender user is set in the mail server. is there.

  An object of the present invention is a secure mail distribution system that solves the problem of increasing the load on a user terminal or a mail server that is a transmission source when an advertisement mail that is distributed in large quantities is transmitted, which is the conventional problem described above. To provide a secure mail delivery apparatus, a secure mail delivery method, and a program.

  Furthermore, another object of the present invention is to provide a secure mail delivery system and secure mail delivery that solve the above-described conventional problem that an electronic certificate issued by a person other than a trusted third party is attached. To provide an apparatus, a secure mail delivery method, and a program.

  A first secure mail distribution system according to the present invention is a secure mail distribution system in which a distribution source user terminal, a secure mail distribution device, a mail server, and a certificate authority are connected by a network. An advertisement mail input from the distribution source user terminal by performing user authentication between the certificate / private key information storage means for storing the electronic certificate and private key corresponding to the original mail address and the distribution source user terminal Based on the information, a distribution control unit that generates a mail text for each destination mail address, and searches the electronic certificate and the private key corresponding to the distribution source mail address from the certificate / private key information storage unit, Create an electronic signature using a private key and attach it to the body of the email along with the electronic certificate to make a signed email. It characterized by having a signature processing means for transmitting to the mail server.

  The second secure mail distribution system according to the present invention is the second secure mail distribution system, wherein the secure mail distribution device further includes, from the certificate authority, the electronic certificate and the secret corresponding to the distribution source mail address. It has certificate information acquisition means for acquiring a key and storing it in the certificate / private key information storage means.

  A third secure mail distribution system according to the present invention is the first or second secure mail distribution system, wherein the secure mail distribution device further stores destination user attribute information corresponding to the destination mail address. Information storage means and insertion information storage means for defining an insertion character string corresponding to the attribute information, wherein the distribution control means is configured to send the destination information from the destination user information storage means and the insertion information storage means. The mail text is generated by searching the insertion character string corresponding to the mail address and inserting it into a text template input from the distribution source user terminal.

  According to a fourth secure mail distribution system of the present invention, in the secure mail distribution system according to any one of the first to third aspects, the signature processing unit sends the distribution source mail address from the certificate / private key information storage unit. When the electronic certificate and the private key corresponding to the URL cannot be retrieved, the mail text is transmitted to the mail server as an unsigned email without attaching the electronic signature and the electronic certificate. And

  The first secure mail delivery apparatus of the present invention performs user authentication between a certificate / private key information storage means for storing an electronic certificate and a private key corresponding to a delivery source mail address, and a delivery source user terminal. , Based on the advertisement mail information input from the distribution source user terminal, a distribution control means for generating a mail text for each destination mail address, and the certificate / private key information storage means corresponding to the distribution source mail address Signature processing means for searching for an electronic certificate and the private key, creating an electronic signature using the private key, attaching the electronic certificate together with the electronic mail body, and transmitting the electronic certificate as a signed electronic mail to a mail server; It is characterized by having.

  According to a second secure mail delivery device of the present invention, in the first secure mail delivery device, the secure mail delivery device further receives from the certificate authority the electronic certificate and the private key corresponding to the delivery source mail address. And certificate information acquisition means for storing it in the certificate / private key information storage means.

  According to a third secure mail delivery apparatus of the present invention, in the first or second secure mail delivery apparatus, the secure mail delivery apparatus further stores destination user attribute information corresponding to the destination mail address. An information storage means, and an insertion information storage means for defining an insertion character string corresponding to the attribute information, wherein the distribution control means sends the destination mail from the destination user information storage means and the insertion information storage means. The mail text is generated by searching the insertion character string corresponding to the address and inserting it into a text template input from the distribution source user terminal.

  A fourth secure mail delivery apparatus according to the present invention is the secure mail delivery apparatus according to any one of the first to third aspects, wherein the signature processing means sends the certificate / private key information storage means to the delivery source mail address. When the electronic certificate and the private key corresponding to the URL cannot be retrieved, the mail text is transmitted to the mail server as an unsigned email without attaching the electronic signature and the electronic certificate. And

  A first program of the present invention is a distribution control process for performing user authentication with a distribution source user terminal and generating a mail text for each destination mail address based on advertisement mail information input from the distribution source user terminal. And searching for the electronic certificate and the private key corresponding to the distribution source mail address from the certificate / private key information storage means for storing the electronic certificate and the private key corresponding to the distribution source mail address, and the private key A secure mail delivery apparatus is configured to create a digital signature using, attach it to the mail text together with the electronic certificate, and send the signed electronic mail to a mail server as a signed electronic mail.

  According to a second program of the present invention, in the first program, the secure mail delivery device further obtains the electronic certificate and the private key corresponding to the delivery source mail address from a certificate authority, and Certificate information acquisition processing stored in the certificate / private key information storage means is performed by the secure mail delivery apparatus.

  According to a third program of the present invention, in the first or second program, the distribution control process corresponds to destination user information storage means for storing destination user attribute information corresponding to the destination mail address and the attribute information. The mail text is retrieved by searching the insertion character string corresponding to the destination mail address from the insertion information storage means for defining the insertion character string to be inserted and inserted into the text template input from the distribution source user terminal. Is generated.

  A fourth program of the present invention is the electronic certificate according to any one of the first to third aspects, wherein the signature processing corresponds to the distribution source mail address from the certificate / private key information storage unit. If the private key cannot be retrieved, the mail text is transmitted to the mail server as an unsigned e-mail without attaching the electronic signature and the electronic certificate.

  According to a first secure mail delivery method of the present invention, a secure mail delivery apparatus performs user authentication with a delivery source user terminal, and based on advertisement email information input from the delivery source user terminal, for each destination email address. A distribution control step for generating a mail body in a message, and a secure mail distribution device corresponding to the distribution source mail address from a certificate / private key information storage means for storing an electronic certificate and a private key corresponding to the distribution source mail address A signature processing step of searching the electronic certificate and the private key, creating an electronic signature using the private key, attaching the electronic certificate together with the electronic mail body, and transmitting the electronic certificate as a signed electronic mail to a mail server; It is characterized by including.

  According to a second secure mail delivery method of the present invention, in the first secure mail delivery method, the secure mail delivery device further receives, from a certificate authority, the electronic certificate and the private key corresponding to the delivery source mail address. And obtaining certificate information stored in the certificate / private key information storage means.

  The third secure mail delivery method of the present invention is the destination user information storage means in which the delivery control step stores the attribute information of the destination user corresponding to the destination mail address in the first or second secure mail delivery method. The insertion character string corresponding to the destination mail address is retrieved from the insertion information storage means that defines the insertion character string corresponding to the attribute information, and is inserted into the body text template input from the distribution source user terminal. The mail text is generated by inserting.

  According to a fourth secure mail delivery method of the present invention, in the secure mail delivery method according to any one of the first to third aspects, the signature processing step is performed by sending the source mail address from the certificate / private key information storage unit. When the electronic certificate and the private key corresponding to the URL cannot be retrieved, the mail text is transmitted to the mail server as an unsigned email without attaching the electronic signature and the electronic certificate. And

  The effect of the present invention is that, in a secure mail system in which an electronic signature and an electronic certificate are attached to an e-mail using a public key cryptosystem, the sender is The load on user terminals and mail servers can be reduced. The reason is that a secure mail distribution device is provided between the distribution source user terminal and the mail server, and the secure mail distribution device uses a plug-in process for creating a different mail text for each destination user and the distribution source user's private key. This is because a signature process for creating an electronic signature and attaching it to an e-mail together with an electronic certificate is executed collectively.

  Next, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the configuration of a secure mail delivery system in an embodiment of the present invention. Referring to FIG. 1, the embodiment of the present invention includes a distribution source user terminal 10, a secure mail distribution device 20, a mail server 30, a firewall 40, a certificate authority 50, and a destination user terminal 60. The firewall 40, the certificate authority 50, and the destination user terminal 60 are connected by the Internet network 70. Further, the secure mail delivery apparatus 20 and the mail server 30 are connected by the same network, and communication via the Internet network 70 is restricted by the firewall 40. Communication between the secure mail delivery apparatus 20 and the Internet network 70 is limited to communication using the HTTP protocol or HTTPS protocol, and communication between the mail server 30 and the Internet network 70 is limited to transmission / reception of electronic mail.

  The distribution source user terminal 10 is a terminal device for the user to input the advertisement mail information 71 that is information related to the advertisement mail, and is connected to the secure mail distribution apparatus 20.

The secure mail delivery device 20 is an information processing device such as a personal computer or a workstation that operates under program control, and includes a delivery control unit 21, a signature processing unit 22, a certificate information acquisition unit 23, and a distribution source user information storage unit 81. , A destination user information storage unit 82, a plug-in information storage unit 83, and a certificate / private key information storage unit 84.
The distribution control unit 21 performs authentication processing of the distribution source user, and based on the advertisement mail information 71 transmitted from the distribution source user, inserted mail information in which a character string suitable for each destination user is inserted into the text. 72 is generated and transmitted to the signature processing unit 22.

  The signature processing unit 22 generates an electronic signature for the inserted mail information 72, creates a signed electronic mail 73 with an electronic signature and an electronic certificate added, and transmits the electronic mail 73 to the mail server 30.

  The certificate information acquisition unit 23 acquires the private key / electronic certificate of the distribution source user from the certificate authority 50 on behalf of the certificate authority 50 and stores it in the certificate / private key information storage unit 84.

  The distribution source user information storage unit 81 stores and manages attribute information about the distribution source user such as the user ID, password, and e-mail address of the distribution source user.

  The destination user information storage unit 82 stores and manages attribute information related to the destination user, such as the e-mail address, date of birth, and sex of the destination user of the advertisement mail.

  The insertion information storage unit 83 stores and manages an insertion character string to be inserted into the text of the advertisement mail according to the attribute information (birth date, sex, etc.) of the destination user.

  The certificate / private key information storage unit 84 stores and manages the private key / electronic certificate of the distribution source user acquired from the certificate authority 50 in association with the electronic mail address of the distribution source user.

  The mail server 30 supports the SMTP protocol, and transmits the signed electronic mail 73 received from the secure mail delivery apparatus 20 to the destination user terminal 60.

  The certificate authority 50 is a reliable third-party certification body that issues an electronic certificate that proves the existence of a company or organization, and an electronic certificate that proves that the distribution source user exists and the distribution source user Issue a private key for use in electronic signatures.

  The destination user terminal 60 is a terminal device for the destination user to receive the advertisement mail, and includes a reception processing unit 61 and a certificate information storage unit 91. The reception processing unit 61 confirms the reliability of the distribution source of the signed e-mail 73 transmitted from the secure mail distribution device 20 and confirms whether or not it has been tampered with. The certificate information storage unit 91 stores the electronic certificate acquired from the certificate authority 50.

  Next, the operation of the embodiment of the present invention will be described with reference to the drawings.

[Certificate acquisition processing]
FIG. 2 shows an operation flow of the certificate acquisition process. The certificate acquisition process is to acquire the electronic certificate and private key of the distribution source user from the certificate authority 50 on behalf of the distribution source user, and by the distribution source user who desires the signature processing in the secure mail distribution device 20, It is activated when there is a request for obtaining an electronic certificate. First, it is assumed that the secure mail delivery apparatus 20 has information that proves the existence of the delivery source user and the public key of the delivery source user that are necessary for the certificate authority 50 to issue an electronic certificate.

  The certificate information acquisition unit 23 of the secure mail distribution device 20 transmits a certificate issuance request including information for proving the existence of the distribution source user and the public key of the distribution source user to the certificate authority 50 (step A101). The certificate authority 50 confirms the information included in the certificate issuance request (step B101), and if it is determined that the electronic certificate can be issued, the certificate authority 50 generates an electronic certificate and a private key including the public key of the distribution source user. (Step B102), the certificate issuance response is transmitted to the secure mail delivery apparatus 20 (Step B103). The secure mail distribution device 20 stores the received electronic certificate and private key in the certificate / private key information storage unit 84 in association with the electronic mail address of the distribution source user (step A102).

[Authentication and plug-in processing]
FIG. 3 shows an operation flow of authentication / insertion processing. In the authentication / insertion processing, the distribution control unit 21 of the secure mail distribution device 20 performs authentication processing for the distribution source user, and based on the advertisement mail information 71 transmitted from the distribution source user, characters suitable for each destination user. This is a process for inserting the column into the text and creating the inserted mail information 72.

  The distribution control unit 21 of the secure mail distribution device 20 receives the input of the user ID and password from the distribution source user terminal 10 (step A201), and whether the user ID and password match the contents of the distribution source user information storage unit 81. Authentication processing is performed by confirming whether or not (step A202). If the authentication process fails, the process ends as an authentication error (steps A203 and A204). If the user authentication is successful, the distribution control unit 21 receives the input of the advertisement mail information 71 from the distribution source user terminal 10 (step A205). As shown in FIG. 6, the advertisement mail information 71 includes a distribution source mail address, a destination mail address list, a reply destination mail address, an error reply destination mail address, a subject, and a text template. In the body template, a common character string that is common regardless of the destination user and an insertion position that indicates a position where a different character string is inserted for each destination user are defined.

  Next, the delivery control unit 21 confirms the format of the advertisement mail information 71 as to whether or not the format is appropriate as an e-mail (step A206). The format confirmation includes confirmation of whether the email address contains “@”, whether the account part of the email address uses “!”, “#”, Etc., or the format defined by RFC2822. Check if it complies with. Furthermore, a check is made as to whether characters that can be displayed only on a specific operating system are used in the text. If the result of the format confirmation is not appropriate as an e-mail, the process is terminated as a format error (steps A207 and A208).

  When the format confirmation is successful, the distribution control unit 21 acquires the attribute information of the destination user from the destination user information storage unit 82 for one of the destination email addresses described in the destination email address list of the advertisement email information 71. (Step A209) Further, an insertion character string corresponding to the attribute information of the destination user is acquired from the insertion information storage unit 83 (Step A210), and inserted by inserting it into the insertion position of the body template. A completed text is created (step A211). The distribution control unit 21 repeats Steps A209 to A211 for all the destination mail addresses described in the destination mail address list (Step A212). The distribution control unit 21 transmits the inserted mail information 72 to the signature processing unit (step A213). As shown in FIG. 6, the inserted mail information 72 includes a distribution source mail address, a reply destination mail address, an error reply destination mail address, a subject, and a destination mail address-inserted text list.

[Signature processing]
FIG. 4 shows an operation flow of the signature processing. In the signature processing, the signature processing unit 22 of the secure mail delivery apparatus 20 generates an electronic signature for the inserted mail information 72, creates a signed electronic mail 73 with an electronic signature and an electronic certificate added thereto, This is a process of transmitting to the mail server 30.

  The signature processing unit 22 of the secure mail delivery apparatus 20 defines and initializes the temporary storage area x for the private key and the electronic certificate (step A301). The signature processing unit 22 searches the certificate / private key information storage unit 84 to obtain a private key and an electronic certificate corresponding to the distribution source mail address (step A302).

  If there is a private key and electronic certificate corresponding to the distribution source mail address in step A302, the signature processing unit 22 saves the private key and electronic certificate in the temporary storage area x (step A304). Subsequently, the signature processing unit 22 obtains a hash value of the inserted body for one set of destination mail address and inserted body described in the destination mail address-inserted body list, and generates a message digest. (Step A305). The signature processing unit 22 encrypts the message digest using the RSA method with the secret key stored in the temporary storage area x, and creates an electronic signature (step A306). The signature processing unit 22 adds the electronic signature and temporary storage area created in step A306 to the delivery source email address, reply destination email address, error reply destination email address, subject and inserted text included in the inserted email information 72. An electronic certificate stored in x is attached in the S / MIME format to create a signed electronic mail 73 (step A307, FIG. 6). The signature processing unit 22 repeats steps A305 to A307 for all destination email addresses described in the destination email address-inserted text list, thereby creating a signed email 73 for all destination email addresses. (Step A308). The signature processing unit 22 transmits all the created signed e-mails 73 to the mail server 30 (step A309).

  In step A302, if there is no private key or electronic certificate corresponding to the distribution source mail address, the difference between the set of destination mail address and the inserted text described in the destination mail address-inserted text list is An unsigned e-mail is created from the distribution source e-mail address, reply destination e-mail address, error reply destination e-mail address, subject, and inserted text included in the embedded e-mail information 72 (step A310). The signature processing unit 22 creates unsigned e-mails for all the destination e-mail addresses by repeating step A310 for all the destination e-mail addresses described in the destination e-mail address-inserted text list (step A311). ). The signature processing unit 22 transmits all created unsigned e-mails to the mail server 30 (step A312).

  The mail server 30 transmits the signed e-mail 73 or unsigned e-mail received from the secure mail distribution apparatus 20 to the destination e-mail address using SMTP.

[Receive processing]
FIG. 5 shows an operation flow of reception processing of the signed electronic mail 73. In the reception process, the destination user terminal 60 that has received the signed e-mail 73 uses the electronic signature and electronic certificate added to the received e-mail to confirm the reliability of the advertisement mail distribution source, This is a process for confirming that there is no tampering.

  The reception processing unit 61 of the destination user terminal 60 searches the certificate information storage unit 91, and stores an electronic certificate having an identifier that matches the certificate identifier of the electronic certificate attached to the received electronic mail. Whether or not is confirmed (step C101). If the corresponding certificate exists, the process proceeds to step C106 (step C102).

  If the corresponding certificate does not exist in the certificate information storage unit 91, the reception processing unit 61 connects to the certificate authority 50 via the Internet network 70 and corresponds to the identifier of the electronic certificate attached to the e-mail. The electronic certificate to be searched is retrieved and acquired (step C103). If the corresponding electronic certificate does not exist in the certificate authority 50, the reception processing unit 61 displays that the reliability of the distribution source cannot be confirmed (steps C104 and C105).

  The reception processing unit 61 decrypts the signature data attached to the e-mail using the certificate information storage unit 91 or the public key of the distribution source user included in the electronic certificate acquired from the certificate authority 50, and sends a message A digest is obtained (step C106). The reception processing unit 61 obtains a message digest by calculating a hash value for the body of the received electronic mail, compares it with the message digest obtained from the signature data, and ends the process if they match (steps C107 and C108). . If they do not match, it is displayed that the e-mail has been tampered with (step C109).

  Thus, the operation of the embodiment of the present invention is completed.

  According to the embodiment of the present invention, when a large amount of advertisement mail is transmitted in a secure mail distribution system that transmits an electronic signature with an electronic signature attached to the electronic mail using a public key cryptosystem. In addition, it is possible to reduce the load on the transmission source user terminal and mail server. The reason is that a secure mail distribution device is provided between the distribution source user terminal and the mail server, and the secure mail distribution device uses a plug-in process for creating a different mail text for each destination user and the distribution source user's private key. This is because a signature process for creating an electronic signature and attaching it to an e-mail together with an electronic certificate is executed collectively.

  Further, according to the embodiment of the present invention, in a secure mail distribution system that transmits an electronic signature and an electronic certificate attached to an electronic mail using a public key cryptosystem, the electronic certificate of a trusted third party Can be attached. The reason is that a secure mail distribution device is provided between the distribution source user terminal and the mail server, and the secure mail distribution device is a third party that can trust the distribution source user's electronic certificate and private key on behalf of the distribution source user. This is because it is obtained from a certain certificate authority, stored, and used for signature processing.

  In addition, according to the embodiment of the present invention, in a secure mail system that transmits a digital signature and an electronic certificate attached to an electronic mail using a public key cryptosystem, the distribution source user performs technically advanced processing. It is possible to easily distribute a large amount of e-mails without being conscious of the above. The reason is that, as described above, a secure mail delivery device is provided between the delivery source user terminal and the mail server, and the secure mail delivery device creates a different mail text for each destination user, and the delivery source user. The user of the distribution source creates a digital signature using the private key of the user and attaches it to the email together with the electronic certificate. This is because it is only necessary to input information to the secure mail delivery apparatus.

It is a block diagram which shows embodiment of this invention. It is a figure which shows operation | movement of the certificate acquisition process in embodiment of this invention. It is a figure which shows the operation | movement of the authentication and insertion process in embodiment of this invention. It is a figure which shows the operation | movement of the signature process in embodiment of this invention. It is a figure which shows the operation | movement of the reception process in embodiment of this invention. It is a figure which shows the content of the mail information in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 User terminal 20 Secure mail delivery apparatus 30 Mail server 40 Firewall 50 Certificate authority 60 Destination user terminal 61 Reception processing part 70 Internet network 71 Advertisement mail information 72 Inserted mail information 73 Signed e-mail 81 Distribution source user information storage part 82 Destination user information storage unit 83 Insertion information storage unit 84 Certificate / private key information storage unit 91 Certificate information storage unit

Claims (16)

In a secure mail distribution system in which a distribution source user terminal, a secure mail distribution device, a mail server, and a certificate authority are connected by a network,
The secure mail delivery device includes:
A certificate / private key information storage means for storing an electronic certificate and a private key corresponding to the distribution source mail address;
A delivery control means for performing user authentication with the delivery source user terminal and generating a combination list of a destination email address and a mail text based on the advertisement email information input from the delivery source user terminal;
The electronic certificate and the private key corresponding to the distribution source mail address are retrieved from the certificate / private key information storage means, and the electronic signature is obtained from the private key for each pair of the list using the list. And generating a signed email based on the list, the generated electronic signature, and the electronic certificate, and generating the signed email for the destination email address described in the list, A secure mail distribution system , comprising: signature processing means for transmitting all the generated signed e-mails to the mail server. The secure mail delivery device further includes:
A certificate information acquisition unit that acquires the electronic certificate and the private key corresponding to the distribution source mail address from the certificate authority and stores them in the certificate / private key information storage unit. Item 4. The secure mail delivery system according to item 1. The secure mail delivery device further includes:
Destination user information storage means for storing attribute information of a destination user corresponding to the destination email address;
Having an insertion information storage means for defining an insertion character string corresponding to the attribute information;
The distribution control means searches the insertion character string corresponding to the destination mail address from the destination user information storage means and the insertion information storage means, and inserts it into the body text template input from the distribution source user terminal. 3. The secure mail distribution system according to claim 1, wherein the mail text is generated by inserting the mail. The signature processing means, when the electronic certificate and the private key corresponding to the delivery source mail address could not be retrieved from the certificate / private key information storage means, the mail text, the electronic signature, and the electronic signature The secure mail delivery system according to any one of claims 1 to 3, wherein the secure mail distribution system transmits the unsigned e-mail without an electronic certificate to the mail server. A certificate / private key information storage means for storing an electronic certificate and a private key corresponding to the distribution source mail address;
Distribution control means for performing user authentication with a distribution source user terminal, and generating a combination list of a destination email address and a mail text based on the advertisement mail information input from the distribution source user terminal;
The electronic certificate and the private key corresponding to the distribution source mail address are retrieved from the certificate / private key information storage means, and the electronic signature is obtained from the private key for each pair of the list using the list. And generating a signed email based on the list, the generated electronic signature, and the electronic certificate, and generating the signed email for the destination email address described in the list, A secure mail delivery apparatus , comprising: signature processing means for transmitting all the generated signed electronic mails to a mail server. And a certificate information acquisition unit for acquiring the electronic certificate and the private key corresponding to the distribution source mail address from a certificate authority and storing them in the certificate / private key information storage unit. The secure mail delivery apparatus according to claim 5. The secure mail delivery device further includes:
Destination user information storage means for storing attribute information of a destination user corresponding to the destination email address;
An insertion information storage means for defining an insertion character string corresponding to the attribute information;
The distribution control means searches the insertion character string corresponding to the destination mail address from the destination user information storage means and the insertion information storage means, and inserts it into the body text template input from the distribution source user terminal. 7. The secure mail delivery apparatus according to claim 5, wherein the mail text is generated by inserting the mail. The signature processing means, when the electronic certificate and the private key corresponding to the delivery source mail address could not be retrieved from the certificate / private key information storage means, the mail text, the electronic signature, and the electronic signature 8. The secure mail delivery apparatus according to claim 5, wherein the secure mail distribution apparatus transmits the unsigned e-mail without attaching an electronic certificate to the mail server. A delivery control process for performing user authentication with a delivery source user terminal, and generating a combination list of a destination email address and a mail text based on the advertisement email information input from the delivery source user terminal;
The electronic certificate and the private key corresponding to the distribution source mail address are searched from a certificate / private key information storage means for storing the electronic certificate and the private key corresponding to the distribution source mail address, and the list is used, the generated electronic signature by the secret key for each set of the list, the list, the electronic signature thus generated, and generates a signed e-mail on the basis of the electronic certificate, according to the list A program for causing a secure mail delivery apparatus to perform a signature process for transmitting all of the generated signed e-mails to a mail server after generating the signed e-mail for the destination e-mail address . Further, the secure mail distribution apparatus performs certificate information acquisition processing for acquiring the electronic certificate and the private key corresponding to the distribution source mail address from a certificate authority and storing them in the certificate / private key information storage means. The program according to claim 9, wherein: The distribution control processing includes: a destination user information storage unit that stores attribute information of a destination user corresponding to the destination email address; and a plug-in information storage unit that defines a plug-in character string corresponding to the attribute information. 11. The program according to claim 9, wherein the mail text is generated by searching the insertion character string corresponding to an address and inserting it into a text template input from the distribution source user terminal. . In the signature process, when the electronic certificate and the private key corresponding to the distribution source mail address cannot be retrieved from the certificate / private key information storage unit, the mail text is converted into the electronic signature and the electronic signature. The program according to any one of claims 9 to 11, wherein the program is transmitted to the mail server as an unsigned e-mail without a certificate attached. A distribution control step in which the secure mail distribution device performs user authentication with a distribution source user terminal and generates a combination list of a destination mail address and a mail text based on the advertisement mail information input from the distribution source user terminal When,
The secure mail distribution device obtains the electronic certificate and the private key corresponding to the distribution source mail address from the certificate / private key information storage means for storing the electronic certificate and the private key corresponding to the distribution source mail address. Search and use the list to generate an electronic signature for each set of the list using the private key, and generate a signed e-mail based on the list, the generated electronic signature, and the electronic certificate And a signature processing step of transmitting all of the generated signed emails to a mail server after generating the signed emails for the destination email addresses listed in the list. Delivery method. Further, the secure mail delivery device obtains the electronic certificate and the private key corresponding to the delivery source mail address from a certificate authority, and stores them in the certificate / private key information storage means. 14. The secure mail delivery method according to claim 13, further comprising: The distribution control step includes: a destination user information storage unit that stores destination user attribute information corresponding to the destination email address; and a destination information storage unit that defines an insertion character string corresponding to the attribute information. The secure mail according to claim 13 or 14, wherein the mail text is generated by searching the insertion character string corresponding to an address and inserting it into a text template input from the distribution source user terminal. Mail delivery method. In the signature processing step, when the electronic certificate and the private key corresponding to the delivery source mail address cannot be retrieved from the certificate / private key information storage unit, the mail text is converted into the electronic signature and the electronic signature. The secure mail delivery method according to any one of claims 13 to 15, wherein the electronic mail is transmitted to the mail server as an unsigned electronic mail without attaching an electronic certificate.

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