KR20050063208A - E-mail service system receiving less spam mails using temporary e-mail address and method therefor - Google Patents

Abstract

The present invention relates to a technique for reducing the amount of spam mail sent by spammers by inducing load generation to a system for sending a large number of emails using a temporary email address.

To this end, the present invention is to enable the sender to send an e-mail by allowing the sender to send a mail only in a state in which a temporary e-mail address for the e-mail address of the e-mail recipient secured by the e-mail sender is assigned. It is characterized by reducing the transmission of spam e-mail by increasing the load, thereby preventing mass e-mail transmission.

Description

E-mail service system receiving less spam mails using temporary E-mail address and method therefor}

The present invention relates to a system and method for reducing spam mail, and more particularly, a technique for reducing the amount of spam mails sent by a spammer by inducing a load on a system for sending a large amount of email using a temporary email address. It is about.

The advent of e-mail has provided many Internet users with a free, inexpensive and convenient means of communication, but spam exploits the fact that e-mail addresses can be sent only to those who know the e-mail address of a particular subject. The emergence of (spam) mail has been a significant inconvenience for Internet users. Spam mails have a large social problem that leads to dissemination of pornography, waste of network and computer resources, waste of time and deterioration of work efficiency by the sender's unilateral delivery of unwanted information.

In order to solve this problem, various anti-spam methods have emerged.

For example, a method has been proposed to allow and block e-mail sent from a specific sender by allowing and blocking all e-mail sent from a specific e-mail address. This is an inefficient method, and in reality, there is a problem that spammers cannot effectively block spam mails because the spammers use modified e-mail addresses instead of normally using the sender's e-mail addresses.

In addition, a method of blocking an e-mail containing a specific word by checking a word included in the title or content of the e-mail is also used, which increases the load on the receiving server or the receiving PC. Moreover, since a method of avoiding such a pattern matching technique has been proposed due to the encoding method of various e-mail contents, the above-described method does not efficiently block spam mail.

In addition, a method of blocking e-mail reception from a server by checking a percentage of spam mails sent from a specific server is proposed. It is not widely used because there is a lack of a realistic way to find out the ratio, and in the worst case it can block all normal e-mail. In particular, since it is not used by commercial Internet Service Providers (ISPs) having a large number of customers, there is a disadvantage that users cannot be benefited from blocking spam mails.

Recently, a method of making all these techniques into a rule and assigning weights to each of them and summing the penalties according to the rules has finally appeared. However, this method has a difficulty in generating an optimal rule set by giving an appropriate weight to each rule, and there is a problem that spam mail cannot be completely blocked.

Recently, a specific domestic e-mail service provider has implemented a method of requesting a sender who sends a large amount of e-mail to block spam mail, but this method based on the sender's IP address has some legitimate mass e-mail. It only affected the mailer, but could not regulate the sender of malicious spam by changing its IP address.

Although various and new anti-spam techniques are being developed day by day, spam mail transmission technology will evolve in various ways as long as spam mail is recognized as an inexpensive and efficient medium transmission method while maintaining anonymity for the sender.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and it is possible to send a mail to the recipient only when a temporary e-mail address is assigned to the e-mail address of the e-mail recipient secured by the e-mail sender. It aims to reduce the transmission of spam mails by interfering with the mass mail transmission by increasing the load involved in transmitting the email by the email sender.

In order to achieve the above object, a spam mail reduction system according to the present invention includes a temporary email address decryption unit for determining whether recipient addresses of emails requested to be sent are temporary email addresses; A temporary e-mail address generator for generating a temporary e-mail address for a recipient address determined to be not a temporary e-mail address; And a service control unit configured to deliver a mail to a recipient address configured in the forwarding list by configuring a forwarding list with actual recipient addresses of the e-mails determined as the temporary e-mail address.

In addition, the spam mail reduction method according to the present invention, the first step of extracting the recipient address sequentially from the recipient address list of the sent email request to determine whether the recipient address is a temporary email address format; If the recipient address of the email is not a temporary email address format, giving a sender of the email a temporary email address for the recipient address and terminating the network connection; If the recipient address of the e-mail is in a temporary e-mail address format, decode the recipient address to determine whether the recipient address is a correct e-mail address; If the recipient address is determined to be a valid temporary e-mail address, the actual recipient address corresponding to the temporary e-mail address is stored in a forwarding list, and if the recipient address is not the end of the recipient address list, the process proceeds to the first step. Fourth process; A fifth step of transmitting an error message and terminating a network connection if the recipient address is not determined to be a valid temporary e-mail address as a result of the third step; And a sixth step of sending the e-mail to the recipient address stored in the forwarding list when the recipient address is determined to be the last of the recipient address list in the fourth step.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail.

Spam mail reduction system using a temporary email address according to an embodiment of the present invention, as shown in Figure 1, the temporary email address generation unit 10, the temporary email address decryption unit 20, the service control unit 30 ), And an e-mail service unit 40.

The temporary email address generator 10 generates a temporary email address for a recipient address determined by the temporary email address decoder 20 to not be a temporary email address.

The temporary email address decryption unit 20 determines whether recipient addresses of the requested emails are temporary email addresses and transmits the result to the service control unit 30.

The service control unit 30 forms a forwarding list with the actual recipient addresses of the e-mails whose recipient address is determined to be a temporary e-mail address in the e-mail address decoding unit 20, and delivers the e-mail to the recipient addresses configured in the forwarding list. And controlling the temporary email address generator 10 to generate a temporary email address for a recipient address, not a temporary email address, to deliver the temporary email address to the email sender, and to terminate the network connection. .

Next, a spam mail reduction method using a temporary e-mail address according to an embodiment of the present invention will be described in detail with reference to the flowchart shown in FIG. 2.

The e-mail client 50 connects to the e-mail service unit 40 and presents its e-mail address using the 'MAIL FROM' command of the Simple Mail Transfer Protocol (SMTP), and then uses the 'RCPT TP' command. Enter the e-mail addresses of the recipients you want to send e-mail one by one.

The e-mail service unit 40 transmits the sender e-mail address and the recipient e-mail address to the service control unit 30, and the service control unit 30 registers the recipient e-mail address in the recipient address list, and then temporarily In cooperation with the postal address decoding unit 20, it is checked whether an e-mail address included in the recipient address list is a correct temporary e-mail address (S6).

As a result of the check, if it is determined that the temporary e-mail address of the recipient is not a correct e-mail address (No in step S6), the e-mail service unit 40 is controlled to send an appropriate error message, and then the e-mail. After the network connection with the client 50 is terminated, and if the recipient's email address is determined to be a valid temporary email address (YES in step S6), the recipient's actual email address is added to the forwarding list ( S8) It is checked whether the email address is the last email address of the recipient address list, that is, the last recipient email address input from the email client 50 (S10).

As a result of the check, if the e-mail address is not the last e-mail address of the recipient address list (NO in S10), the process proceeds to step S4 to extract the next recipient address in the recipient address list, and then steps S6 to S10. Proceed.

However, if the e-mail address is confirmed as the last e-mail address of the recipient address list as a result of the determination of step S10 (YES in S10), the body content of the e-mail to be transmitted from the sender using the 'DATA' command of STMP After receiving the input (S12), and sends the e-mail to the recipient included in the delivery list (S14).

Therefore, the existing e-mail system can send all the e-mail through one network connection no matter how many recipients, the e-mail system applied to the present invention attempts to send e-mail without having a valid temporary e-mail address In this case, you should repeat network access to the e-mail system at least as long as the recipient list. This network connection repetition is rarely a problem for most normal email exchanges with a small list of recipients, but it creates a load proportional to the number of recipients for senders (spammers) who want to send large amounts of email. It plays a role in reducing the efficiency and economy in the transmission of mail through the network.

In addition, this frequent network connection is monitored under a network equipped with a network surveillance system, so that a sender who attempts to send a large amount of spam mail is monitored at the network level, not at the application level.

For example, a sender with an e-mail address spammer@spam.com extracts all e-mail addresses ending in @ antispam.com from a large list of e-mail addresses they have, and has an IP address of 169.254.1.2. Assume that you send a large amount of spam mail using your PC. The list of email addresses the sender wants to send is a001@antispam.com; a002@antispam.com; , 100 such as a100@antispam.com.

The sender attempts an SMTP connection to an e-mail server in the domain, first notifying his or her e-mail address, and subsequently informing the list of recipient addresses in the list of e-mail addresses. Existing mail systems can send e-mails to 100 people through this one-time connection. However, in the e-mail system of the present invention, if a valid temporary e-mail address is not confirmed at the time of notifying the e-mail address of the first recipient, an error message is sent. By assigning the sender a valid temporary e-mail address that can be used for a certain period of time, the network connection is terminated.

Therefore, the sender must repeat the network connection at least 100 times to obtain a valid temporary e-mail address for 100 recipients.

A detailed procedure of determining whether the recipient address in the recipient address list is a valid temporary recipient address in step S6 shown in FIG. 2 will be described with reference to the flowchart shown in FIG. 3.

First, it is determined whether the type of the input e-mail address is in the form of a temporary e-mail address (S20, S22). The temporary e-mail address can be implemented in various forms, but a tag (1) indicating that the e-mail address is a normal e-mail address of a normal real user and the sender's e-mail address, sender's IP address, validity period, and recipient's e-mail address It must contain the value (2) encrypted with. For example, an e-mail address such as user0000@antispam.com is a temporary e-mail address and a tag called 'temp' is added, and the encrypted information such as' qx93d04plx6783463anv9443xx012455 'is added to' user000-qx93d04plx6783463anv9443xx012455 @ temp .antispam.com ' At this time, DNS should be properly set so that the e-mail system can handle the changed domain temp.antispam.com.

In step S22, it is checked whether the recipient's email address is in the temporary email address format as described above, and if the recipient's email address is not in the temporary email address format (NO in S22), the service control unit 30 In association with the temporary email address generator 10, a new temporary email address is generated for the address of the recipient (S24).

When a new temporary e-mail address is generated, the service control unit 30 sends an error message such as 'User Moved: user000-qx93d04plx6783463anv9443xx012455@temp.antispam.com' on the SMTP through the e-mail service unit 40, and establishes a network connection. It ends (S26, S28). At this time, the program sending the e-mail will attempt to resend the e-mail using the changed recipient address if the error message can be interpreted. If the error message cannot be interpreted, it is an error message on the SMTP. This can be delivered in the form of e-mail.

If a recipient address that satisfies the format of the temporary email address is input, the process proceeds to step S30 according to the determination result in step S22 to decode the receiver address to sender email address and sender IP from the receiver address. The address, validity period, etc. are extracted (S30).

Subsequently, the service control unit 30 determines whether the extracted sender email address matches the email address presented by the sender (S32), and if the extracted sender email address is identical to the email address presented by the sender. If it does not match, the temporary e-mail address may be used by another sender. Thus, an error message such as 'Invaild E-Mail Address' is transmitted (S33), and the network connection is terminated by step S28.

If the extracted sender email address matches the email address presented by the sender, it is determined whether the sender IP address matches the current SMTP client IP address (S34). After sending an error message such as 'Invaild E-Mail Address', close the network connection.

If it is determined that the sender IP address matches the current SMTP client IP address, after confirming that the current time is included in the mail transmission validity period (S36), if the current time is not included in the mail transmission validity period, it is valid for the sender. After transmitting the period-related error message (S38), the process proceeds to step S28 to terminate the network connection.

On the other hand, as a result of checking in step S36, if the current time is included within the validity period of mail transmission, it is assumed that the mail has presented a valid temporary email address.

A procedure for generating a temporary email address in the temporary email address generator 10 will be described in detail with reference to FIG. 4.

The temporary e-mail address generator 10 applies the sender IP address 61, the sender e-mail address 62, and the server key 63 to a shared key encryption function to output the temporary key 1 65, and then sends the sender. Temporary key 2 (69) is calculated by applying IP address 61, sender email address 62, expiration date 66, and recipient email address 67 to a shared key encryption function.

When the encryption process is completed, the temporary email address generation unit 10 converts the temporary key 2 69, which is binary data, into a text form through an encoding technique such as Base 64 so as to insert the temporary key 2 69 into the email address ( 70, a temporary key 3 72 is calculated, and the recipient e-mail address 67 is separated into a recipient ID 74 and a recipient domain 75 (73).

The temporary key 3 72, recipient ID 74, and recipient domain 75 are then combined (76) to generate a temporary email address (77).

According to the process of generating the temporary e-mail address shown in FIG. 4, one temporary e-mail address is used to send an e-mail to a recipient having a certain e-mail address through a client having a certain IP address. Information about whether to authorize transmission is included.

In addition, the sender needs an encryption process and a 'server key' so that the sender cannot easily decrypt it and generate a valid temporary e-mail address by itself. The 'server key' can be safely stored on the system because it does not need to be transmitted to the outside. You can change it frequently.

Rather than encrypting all the necessary information at once, encrypting them in two is to implement the ability to generate temporary e-mail addresses on their own by assigning a temporary key 1 to an authorized bulk mailer. This is for friendly bulk email senders. Senders with 'temporary key 1' can generate temporary email addresses themselves through validity periods and recipient email addresses, enabling bulk email transmissions without load. However, since the 'temporary key 1' includes a unique sender e-mail address and an IP address, the third sender cannot use it even if it is leaked to the third sender. The sender's e-mail address and IP address use the sender's information that attempted to send the e-mail to generate a temporary e-mail address. The sender receives the e-mail only when the sender resends the e-mail again without changing the environment. Even if a postal address is used interchangeably between bulk email senders, it is not useful.

The selection of the validity period is necessary to set the validity period only for a time which is not long from the time when any information has passed from the current time of generating the temporary email address. For example, if the validity period of the temporary e-mail address is set to be valid after 20 minutes of the current time, even if the e-mail sender acquires the temporary e-mail address, the e-mail cannot be sent immediately until 20 minutes have elapsed.

Therefore, bulk e-mail senders can send e-mail only if they maintain the same IP address during that time, making caller tracking easier.

In addition, if the expiration date is set to 1 day from the present, the bulk e-mail sender cannot use the acquired e-mail address after 1 day and must go through the process of acquiring the e-mail address again.

Mass spam senders may attempt to obtain a service key by hacking cryptographic functions, but this process puts a load on system resources on the sender side, thereby reducing the economics and efficiency of email transmission. Even if the spammer obtains the service key, changing the server key will make it impossible to generate a temporary e-mail address. Therefore, spam mail cannot be transmitted.

Next, the procedure of decoding the temporary email address in the temporary email address decryption unit 20 will be described in detail with reference to FIG. 5.

The sender IP address 81, the sender email address 82, and the server key 83 are applied to the shared key encryption function (84) to yield 'temporary key 1' (85), and the recipient's temporary email address. (86) is separated into 'data 1' (88) and recipient ID (89) and recipient domain (90), and then 'data 1' (88) is converted into binary data form (91) to 'data 2' ( 92), and apply 'data 2' 92 and 'temporary key 1' 85 to the shared key decryption function to sender email address 94, sender IP address 95, and validity period 96 , And recipient email address 97 are calculated.

On the other hand, by combining the recipient ID 89 and the recipient domain 90 separated in step 87 to obtain the recipient address 99, the service control unit 30 and the sender e-mail address 82 in S32 of FIG. The sender email address 94 is compared, the sender IP address 81 and the sender IP address 95 are compared in S34 of FIG. 3, and the validity period and the current time are compared in S36 of FIG.

Preferably, the recipient email address obtained in step 97 and the recipient email address obtained in step 99 must match.

In the above-described process, the 'temporary key' 85 is a 'temporary key' in the temporary e-mail address generation process only if the sender maintains the same sender e-mail address and IP address as when the temporary e-mail address was issued. Same as 1 '. Thus, the sender email address, sender IP address, validity period, and recipient address information obtained after using the temporary key 85 as a key while decrypting the temporary email address may sometimes yield meaningless values. However, there is no problem in confirming that these meaningless values are not valid because they are different from the information presented by the sender. If the sender's environment has not changed, the sender's email address, sender's IP address, expiration date, and recipient's address that were inserted when creating the temporary email address are all extracted.

According to the present invention as described above, the mass spam sender can reduce the economical efficiency and efficiency of mass spam mail transmission by reducing the cost and efficiency of the mass spam mail transmission by inducing a load proportional to the number of recipients and the number of transmissions. There is an effect.

On the other hand, the present invention is not limited to the above-described embodiment, but can be modified and modified within the scope not departing from the gist of the present invention, such modifications and changes should be regarded as belonging to the following claims. will be.

1 is a block diagram of a spam mail reduction system using a temporary email address according to an embodiment of the present invention.

2 and 3 is a flowchart for explaining a spam mail reduction method using a temporary email address according to an embodiment of the present invention.

4 is a view for explaining the temporary e-mail address generation process according to an embodiment of the present invention.

5 is a view for explaining the temporary e-mail address decryption process according to an embodiment of the present invention.

Claims (12)

A temporary e-mail address decoding unit for determining whether recipient addresses of the requested e-mails are temporary e-mail addresses; A temporary e-mail address generator for generating a temporary e-mail address for a recipient address determined to be not a temporary e-mail address; And And a service control unit configured to deliver a mail to a recipient address configured in the forwarding list by constructing a forwarding list with actual recipient addresses of e-mails determined as a temporary e-mail address. The method of claim 1, wherein the temporary email address generator Applying the sender's IP address, sender's e-mail address, and server key to the first shared key encryption function yields temporary key 1, and sends the sender's IP address, sender e-mail address, expiration date, the temporary key 1, and recipient. After applying the address to the second shared key encryption function to calculate the temporary key 2, the temporary key 3 obtained by converting the temporary key 2 into text, the recipient ID separated from the recipient address, and the recipient domain are combined to generate a temporary key. Spam mail reduction system using a temporary email address, characterized in that for generating a mailing address. The method of claim 2, wherein the temporary email address generation unit Spam mail reduction system using a temporary email address, characterized in that for inserting a tag for identifying the temporary email address in the domain of the temporary email address. The method of claim 2, wherein the temporary email address decryption unit Apply the sender IP address, the sender email address, and the server key to the first shared key encryption function to calculate the temporary key, and separate the temporary postal address into data 1, recipient ID, and recipient domain Apply the data 2 and the temporary key, which convert the data 1 into binary data, to a shared key decryption function to calculate a sender e-mail address, sender IP address, validity period, and recipient address; Spam reduction system using temporary e-mail address, characterized in that to calculate the combined recipient address. The method of claim 1, wherein the service control unit And a temporary email address generated by the temporary email address generator to the email sender, and terminating a network connection. The method of claim 4 or 5, wherein the service control unit The sender email address matches the sender email address extracted from the temporary email address, and the sender IP address matches the sender IP address extracted from the temporary email address, and the current time falls within the validity period. Spam mail reduction system using a temporary e-mail address, characterized in that only if the temporary e-mail address is declared as a valid e-mail address. The method of claim 6, wherein the service control unit Spam mail reduction using a temporary email address, if the recipient address obtained from the temporary email address and the recipient address obtained from the shared key decryption function coincide, the temporary email address is declared as a correct temporary email address. system. A first step of determining whether the recipient address is in a temporary email address format by sequentially extracting a recipient address from a list of recipient addresses of the requested e-mail; If the recipient address of the email is not a temporary email address format, giving a sender of the email a temporary email address for the recipient address and terminating the network connection; If the recipient address of the e-mail is in a temporary e-mail address format, decode the recipient address to determine whether the recipient address is a correct e-mail address; If the recipient address is determined to be a valid temporary e-mail address, the actual recipient address corresponding to the temporary e-mail address is stored in a forwarding list, and if the recipient address is not the end of the recipient address list, the process proceeds to the first step. Fourth process; A fifth step of transmitting an error message and terminating a network connection if the recipient address is not determined to be a valid temporary e-mail address as a result of the third step; And And a sixth step of sending the e-mail to a recipient address stored in the forwarding list when the recipient address is determined to be the last of the recipient address list in the fourth step. Reduction method. 9. The method of claim 8, wherein the temporary email address is Applying the sender's IP address, sender's e-mail address, and server key to the first shared key encryption function yields temporary key 1, and the validity period, the temporary key 1 and the recipient address, is applied to the second shared key encryption function. After calculating the temporary key 2 by using the temporary e-mail address, characterized in that the temporary key 3 converted from the temporary key 2 into text, the recipient ID separated from the recipient address, and the recipient domain are combined. Reduction method. 10. The method of claim 9, wherein the temporary email address is The spam mail reduction method using a temporary e-mail address, characterized in that a tag for identifying a temporary e-mail address is inserted in the domain of the temporary e-mail address. The method of claim 9, wherein in the third process After extracting the sender email address, sender IP address, and valid time by decoding the temporary email address, the extracted sender email address, sender IP address matches the sender email address, sender IP address, and sender IP address present from the sender. And determining the temporary e-mail address as a valid e-mail address when the time falls within the extracted valid time. 12. The method of claim 11 wherein decoding for the temporary email address is Applying the sender IP address, the sender e-mail address, and the server key to the first shared key encryption function to calculate the temporary key 1, and separating the temporary postal address into data 1, recipient ID, and recipient domain. Subsequently, the data 2 converted from the data 1 into binary data and the temporary key 1 are applied to a shared key decryption function to calculate a sender e-mail address, a sender IP address, an expiration date, and a recipient address. Spam reduction method using a temporary email address, characterized in that to calculate the recipient address combined domain.