| 摘要 |
The present invention is to provide a mass mail detection device that eliminates the need for preparation of rules or learning in advance and operates at a high speed. Electronic mail collecting means analyzes the electronic mail delivery protocol that flows on the network, and extracts an electronic mail main text from the electronic mail traffic that flows on the network. Next, characteristic quantity conversion means calculates a number of hash values from the electronic mail main text, as the characteristic quantity of the mail. Finally, mass mail detection means compares the newly received electronic mail with the stored past electronic mails, and determines the similarity in accordance with a specific standard. If determined as being similar, the new mail is determined as a candidate for a mass mail (similar mails), and a prescribed number or more of similar mails are determined as a mass mail.
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