According to popularization of email, spam email is increasing rapidly. It is because email is much cheaper way for advertising than traditional direct mail. Difficulty of measure against spam is that we cannot ignore compatibility between existent servers, because there are too many servers around the world which we can receive email from. Briefly, there are detection of spammer's SMTP, inspection of arrival email by its contents, and whitelisting of legitimate senders, as major measures against spam. We research methods to eliminate spam to keep usability of email.
Papers
Manabu IWANAGA, Toshihiro TABATA, Kouichi SAKURAI
"Evaluation of a scheme against spam by Bayesian filtering and challenge-response",
Computer Security Symposium 2003 (CSS2003), Oct. 2003. (in Japanese)