HASH-BASED SYSTEMS AND METHODS FOR DETECTING AND PREVENTING TRANSMISSION OF UNWANTED E-MAIL

A system (120) detects transmission of potentially unwanted e-mail messages. The system (120) may receive e-mail messages and generate hash values based on one or more portions of the e-mail messages. The system (120) may then determine whether the generated hash values match hash values associated with prior e-mail messages. The system (120) may determine that one of the e-mail messages is a potentially unwanted e-mail message when one or more of the generated hash values associated with the e-mail message match one or more of the hash values associated with the prior e-mail messages.