Spam : the new online scourge in our times

This thesis takes on a broader perspective of the modern age phenomenon we call spam. One of the aims of this thesis is to present and to compare the variety of methods used in the day-to-day fight against spam, as far they have evolved today, but also to present and discuss some alternative methods for suggested future use. The properties of a common e-mail spam are analyzed to show how the components that make up the structure in an e-mail can be used to classify spam. Furthermore I explain the naïve Bayesian classification methods, the signature-based method, the commonly used rule-based method and the challenge and response method and discuss these. The widespread use of blacklists is also explained and a close new variant to blacklisting, Turntide is presented and discussed. This is followed by a brief presentation and discussion of proposed countermeasure methods, including FFBs and Captcha. PHEmail is then shown, a new proposed method which takes advantage of already established social relations, in the fight against spam. Next important step is to present the new legislative bills in USA and in the EC, the criticism regarding these laws is also discussed. The thesis finally presents two suggested methods to fight spam, both initiated by Microsoft: Caller ID and the use of electronic stamps. The thesis rounds off with an open discussion regarding how well this broad variety of methods may interact with each others.Uppsatsnivå: