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Which of the following antispam filtering techniques wo…

Which of the following antispam filtering techniques would BEST prevent a valid, variable-length e-mail
message containing a heavily weighted spam keyword from being labeled as spam?

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A.
Heuristic (rule-based)

B.
Signature-based

C.
Pattern matching

D.
Bayesian (statistical)

Explanation:
Bayesian filtering applies statistical modeling to messages, by performing a frequency analysis on each word
within the message and then evaluating the message as a whole. Therefore, it can ignore a suspicious keywordif the entire message is with innormal bounds. Heuristic filtering is less effective, since new exception rules may
need to be defined when a valid message is labeled as spam. Signature-based filtering is useless against
variable-length messages, because the calculated MD5 hash changes all the time. Finally, pattern matching is
actually a degraded rule-based technique, where the rules operate at the word level using wildcards, and not at
higher levels.


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