KR20040035328A - method for filtering spam mail by X-code - Google Patents

Abstract

PURPOSE: A method for filtering a spam mail of a self-fixed regulation method is provided to automatically filter off an e-mail having a spam sentence performing modification that a letter excepting the letters on a keyboard is inserted between each letter forming a title or a body. CONSTITUTION: If the e-mail is received, a spam checker reads the title of the e-mail(S12). It is judged that the e-mail is a confessed spam mail(S14). In case of a non-confessed spam mail, the spam checker judges that a spam sentence preset in a spam sentence database exists by searching the title of the e-mail(S16). In case that the spam sentence exists, the e-mail is stored to a spam mailbox(S30). If not, it is judged that a modified spam sentence exists in the e-mail(S18). In case that the modified spam sentence exists, the e-mail is stored to the spam mailbox(S30). The spam checker reads a body of the e-mail(S20). The spam checker judges that the spam sentence exists in the body(S24). In case that the spam sentence exists, the e-mail is stored to the spam mailbox. If not, the e-mail is stored to a general mail box(S28).

Description

Method for filtering spam mail by X-code}

The present invention relates to a method for filtering spam mails. In particular, even if various non-letter characters are inserted and modified between each letter of a predetermined spam phrase in a subject or body of an e-mail, it can be classified as spam mail and filtered. It relates to a regular spam filtering method.

As is well known, the e-mail system refers to a system for exchanging data or messages with a specific user through the Internet, and spam-mail refers to advertisements that disregard the intention of the receiving party, Refers to e-mail for commercial purposes, such as propaganda and solicitation. More broadly, commercially available advertising information mails against express opt-out, mass mails sent to deteriorate system performance, advertising mail for illegal software that violates program copyrights, adult goods that harm public morals. And advertisement mails such as unhealthy sites and mails that cause fear or anxiety may be regarded as spam mails.

On the other hand, in order to minimize the harm caused by such spam mails, the government has established various and specific restrictions on spam mails in the Act on Promotion of Information and Communication Network Utilization and Information Protection and its sub-laws. It is taking measures to exceed. For example, at the beginning of a spam message, the phrase "(advertisement)" or "(adult advertisement)" must be displayed. Recipients should install an email with the subject line after the spam filtering program is installed. When set to classify as spam, e-mails with this subject are automatically classified as spam. Furthermore, at present, the mail client may set an arbitrary phrase for filtering the spam mail so that an e-mail including the set phrase in the subject or body content is automatically classified as spam mail. Hereinafter, such a conventional spam filtration method is referred to as a 'self normal method'.

However, according to the conventional technique described above, the e-mail is not the same as the spam text set by the mail client in the subject or body, but the modified spam text, for example, a space, a special character or a pictogram between each letter. In the case where the inserted spam phrase is included, there is a problem in that the filtering of the spam mail cannot be efficiently performed because it cannot be filtered out.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has been improved by conventional spam filtering method of its own regular way to insert a random character other than the letters engraved on the keyboard between each character forming the subject or body, etc. The purpose of the present invention is to provide a self-regulating spam mail filtering method that can filter e-mails with spam phrases that have been executed by the mail.

According to the present invention for achieving the above object, in an e-mail system in which a plurality of mail servers are connected through the Internet, a predetermined spam phrase consisting of two or more letters is present in the subject or body of the received e-mail. In the spam filtering method of the self-regular method to be able to classify and filter the received e-mail to spam mail, at least one or more characters between each character forming the spam phrase in the subject or body of the received e-mail Characterized in that the e-mail is classified as spam if there is a modified spam phrase containing a letter.

1 is a network configuration diagram of a general e-mail system,

2 is a flowchart showing a spam mail filtering method of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

10: own website, 12: mail server,

14 web server, 16: network,

18: mail client, 20: external website,

22: web server, 24: mail server,

30: Internet, 40: Personal mail client

Hereinafter, a spam mail filtering method according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

1 is a network diagram of a general e-mail system. As shown in Fig. 1, the general number of e-mails is transmitted / received by a mail server in which an e-mail client (hereinafter referred to as a “mail client”) 18 connected to the Internet 30 is provided on its own website. (Hereinafter referred to as 'own mail server') 12 or various websites providing e-mail services outside its own website, for example, large and small portal sites or websites of ISPs (20) It can be performed by receiving an e-mail account from a mail server (hereinafter referred to as "external mail server") 24 provided in the.

Its own website 10 has a web server 14 that processes web documents, a mail server 12 and a mail client 18 that are responsible for sending and receiving mail, and a local network 16, for example a LAN or intranet. Is made through the connection. Of course, each external website 20 is also provided with a web server 22 and a mail server 24. In the drawing, reference numeral 40 denotes a personal mail client which accesses the Internet 30 through a telephone line, a cable, a satellite, an ADSL, an ISDN, or the like, mainly at home or a private office, without having a website of its own. The mail client 40 mainly uses the e-mail service after subscribing to the external mail server 24 to receive a mail account for free. Of course, mail clients 18 belonging to its own website 10 can also subscribe to an external mail server 24 to use an e-mail service.

On the other hand, in the above-mentioned e-mail system, e-mail sent by any originating mail client through the internal mail server 12 or the external mail server 24 is transmitted by SMTP (Simple Mail Transfer Protocol). It is stored after being sent to a mailbox of an internal or external mail server 12, 24 represented by an email address of a receiving mail client. Thereafter, the receiving mail client can access his own mailbox via the Internet 30 and read the electronic mail stored therein. The receiving mail client reads its own e-mail by POP3 (Post Office), which copies the e-mail stored in the mailboxes of the mail servers 12 and 24 to the hard disk of the mail client computer. Protocol # 3: Post Office Protocol for Receiving E-Mail from a Mail Server) and IMAP (Internet Message Access Protocol), which allows e-mail received from a mail server to be stored in a mailbox without having to copy it to a mail client computer. There are many methods such as POP3 and IMAP, which are commonly adopted by internal mail server systems.

Recently, in addition to IMAP, a web mail service has been introduced to store incoming mail on the Internet and make it accessible from anywhere. Briefly, the web mail service is a combination of a mail server and a web server. In other words, the webmail server seen from the mail client has the same form as a general web server. Therefore, the mail client only needs a web browser to access the webmail server, and no e-mail software is required. These webmail functions are provided free of charge by various portal sites and ISPs.

2 is a flowchart illustrating a spam filtering method according to the present invention. A program according to the spam filtering method according to the present invention (hereinafter, referred to as a 'spam checker') includes an internal or external mail server 12 and 24. Note that the personal mail client 40 can be integrated or installed separately in the electronic mail software of the client computer.

In addition, hereinafter, 'spam phrase' refers to a set of two or more letters frequently used in spam mails. 'Non-character' refers to a variety of characters other than characters that can be generated through the keyboard, such as numbers displayed on the keyboard, special characters and punctuation symbols, glyphs and spaces not displayed on the keyboard. In the case of Hangul, all characters other than letters generated by 24 Hangul letters become non-letter characters. In the case of English, all non-26 letters are non-letter characters. In addition, "(ad)" and "(ad adult)" are defined in the law, that is, e-mail used without inserting any non-letter characters through the keyboard at the beginning of the e-mail subject is called 'Zine spam mail'. Other spam mails are called 'presumed spam mails'.

First, when any e-mail is received in step S10, the spam checker performs step S12 to read the subject of the received e-mail. Next, in step S14, it is determined whether the corresponding e-mail corresponds to a spam message, and for this purpose, a database storing predetermined phrases, that is, "(advertisement)" and "(adult advertisement)" is operated.

As a result of the determination in step S14, if the received e-mail is a spam mail, the process proceeds to step S26 and stores it in a spam mailbox, preferably 'Zyne spam mailbox'.

Meanwhile, as a result of the determination in step S14, when the received e-mail does not correspond to a self-contained spam mail, the spam checker searches for the subject of the e-mail read in step S16 and is pre-defined in the spam phrase database which is operated by itself. It is determined whether or not the spam text is present as it is. As a result of the determination in step S16, if the spam text defined in the subject of the e-mail is still present, the e-mail is assumed to be spam and the flow proceeds to step S30, where it is stored in the "presumed spam mailbox". According to this, for example, spam phrases such as "advertisement", "adult advertisement", "★ advertisement ★", "♡ advertisement advertisement ♡", "* information", "public information ★", "busy" or "adult site" E-mail that uses a phrase whose title does not contain any non-letter characters between characters may be filtered as spam.

As a result of the determination in step S16, if the spam text as specified in the subject of the e-mail is not used, the subject of the e-mail is processed again by the following formula 1 in step S18, and the modified spam text exists. Judge whether

(Search formula 1)

C ₁ & ... C _n , where n is an integer greater than 1

In the above formula 1, C ₁ and C _n represent each letter constituting the spam phrase pre-registered in the spam phrase database, n represents the number of letters constituting the spam phrase, symbol & represents each letter constituting the spam phrase At least one non-letter character inserted between them. In addition, in order to perform the search equation 1, that is, the spam checker may operate a character database and a character character database. According to this step S18, for example, "advertisement", "advanced sex", "advertisement", "information", "adult ♡ site", "die ★ ad", and the like. Spam texts such as spaces (spaces), pictograms or special characters, etc., are inserted between the letters that make up the spam text defined in the spam text database. There will be.

As a result of the determination in step S18, if there is a modified spam phrase in the subject of the received e-mail, it is estimated as spam mail, and the flow proceeds to step S30 to store in the estimated spam mailbox.

In step S20, the body of the received e-mail is read, and in step S22, it is determined whether or not the spam text as defined in the spam phrase database exists in the text. As a result of the determination in step S22, if there is a spam phrase as defined in the spam phrase database in the body of the e-mail, it is estimated as spam mail, and the flow advances to step S30 to store in the estimated spam mailbox.

In step S24, it is determined whether or not a predetermined spam phrase exists in the spam phrase database in the text. As a result of the determination in step S24, if there is a modified spam phrase in the body of the e-mail, it is estimated as spam mail, and the flow advances to step S30 to store in the estimated spam mailbox. As a result of the determination in step S24, if there is no modified spam phrase in the body of the received e-mail, the flow advances to step S28 to store in the "normal mailbox".

The spam mail filtration method of the present invention is not limited to the above-described embodiment, and can be modified in various ways within the scope of the technical idea of the present invention.

According to the spam mail filtering method according to the present invention as described above, a spam phrase that has been modified by inserting an arbitrary character other than the letters engraved on the keyboard between each letter constituting the subject or body of the e-mail is inserted. The e-mail you have can also be filtered as spam mail, thus improving the filtering efficiency of spam mail.

Claims (3)

In an e-mail system in which a plurality of mail servers are connected through the Internet, a predetermined and two-letter spam phrase is classified as spam mail by filtering the received e-mail as it is in the subject or body of the received e-mail. In its own regular way of filtering spam, Spam mail, characterized in that to classify the received e-mail as a spam mail when there is a modified spam phrase containing at least one or more non-letter characters between each character of the spam phrase in the subject of the received e-mail Filtration method. The method of claim 1, wherein the modified e-mail is classified as spam when there is a modified spam text including at least one non-letter character between the letters constituting the spam text in the received e-mail. Spam mail filtering method, characterized in that. The method according to claim 1 or 2, The spam mail box is classified into a spam mail box and an estimated spam mail box, and the spam mail is stored in the spam mail box and the spam mail other than the spam mail is stored in the estimated spam mail box. How to filter spam.