E-mail filtering systems are faced with the Herculean task of separating out the bad mail from the goodand doing it fast enough so that the mail doesn’t back up. Computer scientists call this a “recognition task” and say it’s one of the most challenging of such tasks that’s ever been devised. CSOs need to make sure that your organization’s e-mail filter system isn’t filtering out wheat with the chaff. Digital signatures will prove necessary if we are going to keep spam from turning spam into a nonviable communication medium.”]
Source: https://www.csoonline.com/article/2118885/how-to-filter-email-with-finesse.html