JP6955459B2 - E-mail system and receiving mail server - Google Patents

Description

The present invention relates to an e-mail system and a receiving mail server that prevent reception of unsolicited e-mail, and particularly to an e-mail system and a receiving mail server that prevent reception of unsolicited e-mail due to spoofing.

In recent years, with the spread of e-mail, the importance of measures against unsolicited e-mail has increased. For example, in Patent Document 1, the sending side mail server and the receiving side mail server store a set of source and destination mail addresses in association with a sending password, and use this sending password. An e-mail system that determines the handling of unsolicited e-mail is disclosed. In this e-mail system, the sending mail server adds a unique header with the sending password to the e-mail and forwards it to the receiving mail server, while the receiving mail server adds a unique header to the e-mail. It is judged whether or not the sending password written in and the stored sending password match, and if they match, it is judged that it is not a junk mail and an e-mail is sent to the receiving user's mail address. do. Here, if the sending passwords do not match, the receiving mail server notifies the sending mail server of a temporary error and waits for resending, while notifying the receiving user terminal of the sending mail address and receiving. Ask if you want to allow. As a result, if permission is obtained by the receiving user, the receiving mail server delivers the resent e-mail, and if permission is not obtained, an error is returned to the sending mail server. As a result, the e-mail that has not been authenticated by the sending password and whose permission has not been obtained by the receiving user is not sent to the receiving user side, and it is possible to prevent receiving the junk e-mail.

Japanese Unexamined Patent Publication No. 2011-180898

However, in the case of the above-mentioned conventional e-mail system, when a person who illegally obtains the sending password generates a junk mail in which the sending password is written in a unique header and sends it to the receiving mail server, it is received. Since the sending passwords match on the side mail server, there is a problem that unsolicited mail is sent to the receiving user side.

The present invention has been made in view of such circumstances, and a main object thereof is to provide an e-mail system and a receiving mail server capable of solving the above-mentioned problems.

In order to solve the above-mentioned problems, the e-mail system according to one aspect of the present invention is an e-mail system including an e-mail sending side mail server and a receiving side mail server. A first setting means for setting a generation rule for generating a password, and a first generation means for generating a password using the generation rule set by the first setting means when an e-mail is received from the sender side. And a first transmission means for transmitting the e-mail to which the password generated by the first generation means is added to the destination side, and the receiving side mail server generates the e-mail password for generating the e-mail. A second setting means for setting a rule, a second generation means for generating a password by using a generation rule set by the second setting means when receiving an e-mail sent from the sending mail server, and a second generation means. A collation means for collating the password attached to the e-mail with the password generated by the second generation means, and when the collation is successful, the e-mail is transmitted to the destination side. 2 It is characterized in that it is provided with a transmission means.

In the above aspect, the first setting means and the second setting means may be configured to set a generation rule determined for each pair of a transmitting side address and a receiving side address.

Further, in the above aspect, the first setting means and the second setting means may be configured to accept the setting of the generation rule from the destination side of the e-mail.

Further, in the above aspect, the sending side mail server and the receiving side mail server further include a determination means for determining whether or not the destination side has the authority to set the generation rule. The 1 setting means and the second setting means may be configured to accept the setting of the generation rule when the determination means determines that the destination side has the authority.

Further, in the above aspect, the first setting means and the second setting means may be configured to accept the setting of the generation rule from the sender side of the e-mail.

Further, in the above aspect, the sending side mail server and the receiving side mail server further include a determination means for determining whether or not the sender side has the authority to set the generation rule. The 1 setting means and the second setting means may be configured to accept the setting of the generation rule when the determination means determines that the source side has the authority.

Further, the receiving side mail server of the present invention is set by the setting means for setting the generation rule for generating the password of the e-mail in the receiving side mail server communicably connected to the sending side mail server, and the setting means. When an e-mail to which a password generated by a set generation rule and a corresponding generation rule is added is received from the sending mail server, a generation means for generating a password using the set generation rule and a generation means. A collation means for collating the password attached to the e-mail with the password generated by the generation means, and a transmission means for transmitting the e-mail to the destination side when the verification is successful by the collation means. It is characterized by having.

According to the e-mail system and the receiving mail server according to the present invention, it is possible to effectively prevent the reception of unsolicited e-mail due to spoofing.

The block diagram which shows the structure of the e-mail system which concerns on Embodiment 1 of this invention, and the communication destination thereof. The block diagram which shows the structure of the receiving side mail server which concerns on Embodiment 1 of this invention. The figure which shows an example of the layout of the address database provided in the receiving side mail server which concerns on Embodiment 1 of this invention. The block diagram which shows the structure of the sending mail server which concerns on Embodiment 1 of this invention. The flowchart which shows the procedure of the generation rule setting process executed by the receiving side mail server and the user terminal which concerns on Embodiment 1 of this invention. The flowchart which shows the procedure of the e-mail reception processing executed by the sending side mail server which concerns on Embodiment 1 of this invention. The flowchart which shows the procedure of the e-mail reception processing executed by the receiving side mail server which concerns on Embodiment 1 of this invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. It should be noted that each of the embodiments shown below exemplifies a method and an apparatus for embodying the technical idea of the present invention, and the technical idea of the present invention is not limited to the following. No. The technical idea of the present invention can be modified in various ways within the technical scope described in the claims.

(Embodiment 1)
[E-mail system configuration]
FIG. 1 is a block diagram showing a configuration of an e-mail system and a communication destination thereof according to an embodiment of the present invention. The e-mail system of the present embodiment is composed of a receiving-side mail server (hereinafter referred to as "reception server") 1 and a sending-side mail server (hereinafter referred to as "sending server") 2 in FIG. The receiving server 1 and the transmitting server 2 are communicably connected to a plurality of user terminals 3, 3, ... Provided on each user side for transmitting and receiving e-mail via the Internet 101. User terminals 3, 3, ... Are composed of devices having a communication function, such as a personal computer, a mobile phone, and a tablet terminal.

[Receiver mail server configuration]
Hereinafter, the detailed configuration of the reception server 1 described above will be described.
FIG. 2 is a block diagram showing the configuration of the receiving server 1. As shown in FIG. 2, the computer (reception server) 1 includes a CPU 11, a ROM 12, a RAM 13, a hard disk 14, and a communication interface (I / F) 15, and these CPU 11, ROM 12, RAM 13, hard disk 14, and communication. The I / F 15 is connected by the bus 16.

The CPU 11 executes various computer programs loaded in the RAM 13. As a result, the computer 1 functions as the receiving server 1 of the present embodiment.

The ROM 12 is composed of a mask ROM, a PROM (Programmable ROM), an EPROM (Erasable PROM), an EEPROM (Electrically Erasable PROM), or the like, and is a computer program executed by the CPU 11 and data used when executing the computer program. Is remembered.

The RAM 13 is composed of an SRAM, a DRAM, or the like. The RAM 13 is used for reading various computer programs stored in the hard disk 14. It is also used as a work area for the CPU 11 when the CPU 11 executes various computer programs.

Various computer programs for execution by the CPU 11 and data used for executing the computer programs are pre-installed on the hard disk 14. Further, the hard disk 14 has an address database (DB) 14A in which a set of a sender address and a receiver address is stored, a generation rule database (DB) 14B in which a password generation rule is stored, and a generation rule. A setting authority database (DB) 14C for storing information on setting authority and a mail database (DB) 14D for storing e-mail are provided. Details of each of these databases will be described later.

Further, a multitasking operating system such as Windows (registered trademark) manufactured and sold by Microsoft Corporation in the United States is installed on the hard disk 14. In the following description, it is assumed that various computer programs run on the operating system.

The communication I / F 15 is an interface device for the receiving server 1 to communicate with an external device via the Internet 101. The receiving server 1 transmits and receives various data between the transmitting server 2 and the user terminals 3, 3, ... Through the communication I / F15.

Hereinafter, details of each database provided on the hard disk 14 will be described.
(A) Address DB14A
FIG. 3 is a diagram showing an example of the layout of the address DB 14A provided in the receiving server 1. As shown in FIG. 3, the address DB 14A includes a registration ID field 111 that stores a registration ID that identifies a pair of a registered sender address and a receiver address, and a sender address field that stores a sender address. It has 112 and a receiver address field 113 in which the receiver address is stored. The address DB 14A stores a set of a sender address and a receiver address provided by the sender and / or receiver of the e-mail.

(B) Generation rule DB14B
The generation rule DB 14B stores a generation rule for generating a password. This generation rule is a rule that can automatically generate a password according to a predetermined procedure, and can generate a different password each time. Specifically, for example, a rule for generating a password by performing a predetermined process at the transmission time of an e-mail is assumed. In the generation rule DB 14B, the generation rule is defined for each pair of the transmitting side address and the receiving side address stored in the address DB 14A.

(C) Setting authority DB14C
The generation rule stored in the generation rule DB 14B is set by the receiver having the setting authority, as will be described later. Information about the setting authority is stored in the setting authority DB 14C. Specifically, information indicating whether or not each user has the setting authority is stored.

(D) Mail DB14D
The mail DB 14D stores the e-mail forwarded from the transmission server 2. However, as will be described later, the e-mail is stored only when the password match can be confirmed on the receiving server 1.

[Sender mail server configuration]
FIG. 4 is a block diagram showing the configuration of the transmission server 2. The configuration of the transmission server 2 is the same as that of the reception server 1 described above. Therefore, in FIG. 4, reference numerals are given to each configuration of the receiving server 1 shown in FIG. 2, and detailed description thereof will be omitted. The generation rule stored in the generation rule DB 24D included in the transmission server 2 is the same as the generation rule stored in the generation rule DB 14D included in the reception server 1.

[Email system operation]
Next, the operation of the e-mail system of the present embodiment configured as described above will be described with reference to a flowchart and the like. In the following, (1) a generation rule setting process for setting a password generation rule, (2) a first e-mail reception process when the transmission server 2 receives an e-mail sent from the sender side, and (3) Details will be described separately for each process of the second e-mail reception process when the receiving server 1 receives the e-mail transferred from the transmitting server 2.

(1) Generation Rule Setting Process FIG. 5 is a flowchart showing a procedure of the generation rule setting process executed by the receiving server 1 and the user terminal 3 of the present embodiment. A user who wishes to receive an e-mail from a specific sender address (hereinafter referred to as "recipient") has a set of the sender address and the e-mail address (receiver address) related to the recipient, and a password. The generation rule is input to the user terminal 3. The user terminal 3 transmits a generation rule setting request including a set of the transmitting side address and the receiving side address and the generation rule input in this way to the receiving server 1 (S101).

When the receiving server 1 receives the generation rule setting request transmitted from the user terminal 3 (S201), the receiving server 1 refers to the setting authority DB 14C, and whether or not the receiver who made the request has the generation rule setting authority. (S202). Here, when it is determined that the user does not have the setting authority (NO in S202), the receiving server 1 transmits the non-configurable information indicating that the generation rule cannot be set to the user terminal 3 (S203). In this case, the user terminal 3 receives the non-settable information (S102), displays it on the display unit (S103), and ends the process.

On the other hand, when it is determined in step S202 that the setting authority is possessed (YES in S202), the receiving server 1 sets the generation rule included in the generation rule setting request by the sender address and the receiver address which are also included. It is linked to the set and registered in the generation rule DB 14B (S204). Next, the receiving server 1 transmits the setting completion information indicating that the setting of the generation rule is completed to the user terminal 3 (S205). When the user terminal 3 receives this setting completion information (S104), it displays it on the display unit (S105). As a result, the receiver can confirm that the generation rule has been set.

As described above, in the present embodiment, the receiver determines the generation rule, but the present invention is not limited to this. For example, the receiving server 1 and the transmitting server 2 may present a plurality of generation rules to the receiver, and the receiver may select a specific generation rule from among them.

The generation rule is registered in the receiving server 1 by the above generation rule setting process, but in the case of the present embodiment, it is necessary to set the same generation rule in the transmitting server 2. Therefore, the receiver accesses the transmission server 2 using the user terminal 3 and transmits the generation rule setting request to the transmission server 2 in the same manner as described above. As a result, the same process as the above-mentioned generation rule setting process is executed between the transmission server 2 and the user terminal 3. As a result, the same generation rule as the generation rule stored in the generation rule DB 14B of the receiving server 1 is stored in the generation rule DB 24B of the transmitting server 2. After the same generation rule is registered in both the receiving server 1 and the transmitting server 2 in this way, the following first and second e-mail receiving processes are executed.

(2) First E-mail Receiving Process A user who sends an e-mail (hereinafter referred to as "sender") instructs a user terminal 3 to send an e-mail after designating a receiving side address. The user terminal 3 that receives this instruction transmits an e-mail including a sender address and a receiver address, which are e-mail addresses related to the sender, to the transmission server 2, and the transmission server 2 receives the e-mail. do. Hereinafter, the details of the first e-mail reception process executed at the time of reception will be described.

FIG. 6 is a flowchart showing a procedure of the first e-mail reception process executed by the transmission server 2 of the present embodiment. As shown in FIG. 6, the transmission server 2 first executes an authentication process for the sender (S301). This authentication process is performed by collating the user ID and password received from the user terminal 3 with the registered user ID and password. Next, the transmission server 2 determines whether or not the authentication was successful based on the result of the authentication process (S302). Here, when it is determined that the authentication has failed (NO in S302), the transmission server 2 transmits reception refusal information indicating that the e-mail cannot be received to the user terminal 3 on the sender side (NO). S303), the process is terminated.

On the other hand, when it is determined in step S302 that the authentication is successful (YES in S302), the transmission server 2 receives the e-mail from the user terminal 3 (S304). Next, the transmission server 2 determines whether or not the generation rule associated with the pair of the sender address and the receiver address of the received e-mail is registered in the generation rule DB 24B (S305). If it is determined that the information is not registered here (NO in S305), the transmission server 2 transmits the reception refusal information to the user terminal 3 (S303), and ends the process.

When it is determined in step S305 that the generation rule is registered (YES in S305), the transmission server 2 generates the password using the generation rule (S306). Next, the transmission server 2 adds the generated password to the e-mail received in step S304 (S307), and transmits the e-mail to the receiving side address (S308).

(3) Second E-mail Reception Process By the above-mentioned first e-mail reception process, an e-mail with a password added is transmitted on the Internet 101. After that, the receiving server 1 receives the e-mail forwarded from the transmitting server 2. Hereinafter, the details of the second e-mail reception process executed at the time of reception will be described.

FIG. 7 is a flowchart showing a procedure of the second e-mail reception process executed by the reception server 1 of the present embodiment. As shown in FIG. 7, the receiving server 1 receives the e-mail forwarded from the transmitting server 2 (S401). Next, the receiving server 1 determines whether or not the generation rule associated with the pair of the sending side address and the receiving side address of the received e-mail is registered in the generation rule DB 14B (S402). If it is determined that the information is not registered here (NO in S402), the receiving server 1 transmits the reception refusal information to the user terminal 3 (S403), and ends the process.

On the other hand, when it is determined in step S402 that the generation rule is registered (YES in S402), the receiving server 1 generates a password using the generation rule (S404). Next, the receiving server 1 collates the generated password with the password added to the e-mail received in step S401, and determines whether or not they match (S405). Here, if it is determined that they do not match (NO in S405), the receiving server 1 transmits the reception refusal information to the user terminal 3 (S403), and ends the process. If it is determined in step S405 that the passwords match (YES in S405), the receiving server 1 registers the e-mail in the mail DB 14D (S406), and ends the process.

If it is determined in step S402 that the generation rule is not registered, or if it is determined in step S405 that the passwords do not match, the sender address and / or subject of the e-mail is sent to the receiving server 1. May be accumulated and the accumulated information may be transmitted to the recipient side by e-mail or the like at an appropriate timing. This makes it possible for the recipient to understand what kind of e-mail is determined to be junk e-mail. This also applies when it is determined in step S305 of the first e-mail reception process that the generation rule is not registered. In that case, the transmission server 2 sends information such as the sender address and / or subject to the receiver side. Will be sent to.

After the second e-mail receiving process is executed, when the receiving server 1 receives the e-mail receiving request from the recipient via the user terminal 3, the receiving server 1 is registered in the mail DB 14D to the user terminal 3. Send an email. This allows the recipient to receive the email.

As described above, in the present embodiment, if the password generated by the generation rule registered in the transmission server 2 and the password generated by the generation rule registered in the reception server 1 are not successfully matched. , The recipient never receives the email. Therefore, for example, even if an unauthorized person impersonates the sender and sends an unsolicited e-mail using a sending mail server different from the sending server 2, the unsolicited e-mail is generated registered in the sending server 2. Since the password generated by the rule is not added, the receiving server 1 does not normally accept the password, and the recipient does not receive the unsolicited mail.

Further, even if an unauthorized person obtains a password generated in the past by the generation rule registered in the transmission server 2 and sends a junk mail after adding the password, the generation rule has a different password each time. Is generated, so that the receiving server 1 does not succeed in verifying the password. Therefore, even in that case, the recipient does not receive the junk mail.

Further, in the case of the present embodiment, since the generation rule is defined for each pair of the sending side address and the receiving side address, the generation rule is more than the case where the same generation rule is applied to all the e-mails. High security can be ensured. In this way, instead of the pair of the sender address and the receiver address, the pair of the sender domain and the receiver address, the pair of the sender address and the receiver domain, or the pair of the sender domain and the receiver domain. Generation rules may be specified for each group. Even in this case, it is possible to ensure higher security than when the same generation rule is applied to all e-mails.

Further, in the case of the present embodiment, since the generation rule is set by the receiver in the receiving server 1 and the sending server 2, it is possible to avoid receiving the e-mail from a person who is not expected by the receiver, and the junk e-mail. Is prevented from being received. Since the generation rule can be set only when the receiver has the setting authority, it is possible to prevent the generation rule from being set illegally.

(Embodiment 2)
In the e-mail system of the first embodiment, the receiver sets the generation rules in the receiving server 1 and the transmitting server 2. On the other hand, in the e-mail system of the present embodiment, the sender sets the generation rules in the receiving server 1 and the sending server 2.

The configuration of the e-mail system of the present embodiment is the same as that of the first embodiment. Further, the process executed by the e-mail system of the present embodiment is the same as that of the first embodiment, but in the generation rule setting process, the e-mail is transmitted to a specific receiving address. The desired sender inputs a set of the receiving side address and the e-mail address (sending side address) related to the sender and the password generation rule to the user terminal 3, and the user terminal 3 inputs such information. It is different from the case of the first embodiment in that the generation rule setting request including the above is transmitted to the receiving server 1. By such a generation rule setting request, the generation rule is set by the sender. By making it possible to set the generation rule only by the sender who is trusted by the receiving server 1 and the transmitting server 2, it is possible to prevent the junk mail from being transmitted.

(Other embodiments)
In the above embodiment, the same generation rule is set for the receiving server 1 and the transmitting server 2, but if the generation rule is capable of generating a collating password, different ones may be set for each. good. That is, the first generation rule set in the receiving server 1 and the second generation rule set in the sending server 2 are different from each other, and the first password and the second generation rule generated from the first generation rule are used. Even if the generated second password is different, it does not matter as long as the first password and the second password can be collated on the receiving server 1.

Further, in the above-described embodiment, the functions of the receiving server 1 and the transmitting server 2 are realized by a single computer, but for example, the receiving server 1 and the transmitting server 2 are each realized by a distributed system consisting of a plurality of computers. The function may be realized, and various aspects are assumed.

1 Receiving mail server 11 CPU
12 ROM
13 RAM
14 Hard disk 14A Address database 14B Generation rule database 14C Setting authority database 14D mail database 15 Communication interface 16 Bus 2 Sending mail server 21 CPU
22 ROM
23 RAM
24 Hard disk 24A Address database 24B Generation rule database 24C Setting authority database 24D Mail database 25 Communication interface 26 Bus 3 User terminal 101 Internet

Claims (7)

In an e-mail system including an e-mail sending side mail server and a receiving side mail server,
The sending mail server
The first setting means to set the generation rule for generating the password of the e-mail, and
When an e-mail is received from the sender side, the first generation means for generating a password using the generation rule set by the first setting means, and the first generation means.
It is provided with a first transmission means for transmitting an e-mail with a password generated by the first generation means to a destination side.
The receiving mail server
A second setting method for setting generation rules for generating email passwords,
When the e-mail sent from the sending mail server is received, the second generation means for generating the password using the generation rule set by the second setting means, and the second generation means.
A collation means for collating the password attached to the e-mail with the password generated by the second generation means.
An e-mail system comprising a second transmission means for transmitting the e-mail to a destination side when the collation is successful by the collation means. The first setting means and the second setting means are configured to set a generation rule determined for each pair of a transmitting side address and a receiving side address.
The e-mail system according to claim 1. The first setting means and the second setting means are configured to receive the setting of the generation rule from the destination side of the e-mail.
The e-mail system according to claim 2. The sending mail server and the receiving mail server
Further provided with a determination means for determining whether or not the destination side has the authority to set the generation rule.
The first setting means and the second setting means are configured to accept the setting of the generation rule when the determination means determines that the destination side has the authority.
The e-mail system according to claim 3. The first setting means and the second setting means are configured to receive the setting of the generation rule from the sender side of the e-mail.
The e-mail system according to claim 2. The sending mail server and the receiving mail server
Further provided with a determination means for determining whether or not the source side has the authority to set the generation rule.
The first setting means and the second setting means are configured to accept the setting of the generation rule when it is determined by the determination means that the source side has the authority.
The e-mail system according to claim 5. In the receiving mail server that is communicatively connected to the sending mail server
Setting means for setting generation rules for generating email passwords, and
When an e-mail to which a password generated by a generation rule corresponding to a generation rule set by the setting means is added is received from the sending mail server, a password is generated using the set generation rule. Generation means and
A collation means for collating the password attached to the e-mail with the password generated by the generation means.
A receiving side mail server including a transmitting means for transmitting the e-mail to the destination side when the matching is successful by the matching means.

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