So Razor differs from DCC in that respect. I gave up on Razor long ago due to delays due to slow Razor response, and repeated Razor outages. Is it more reliable today?
<<Dan>> > -----Original Message----- > From: Matt Kettler [mailto:[EMAIL PROTECTED] > Sent: Tuesday, November 30, 2004 5:12 PM > To: Smart,Dan; users@spamassassin.apache.org > Subject: Re: Image Composition Analysis > > At 05:27 PM 11/30/2004, Smart,Dan wrote: > >Messagelabs made a big deal of their option of using First > 4 Internet's > >Image Composition Analysis tool to detect pornographic images. Is > >anyone in the open source world working on something similar. > > Not that I'm aware of. Nor am I particularly impressed with > the First 4 tool. It seems to operate mostly by detecting > what percentage of an image is "skintone", leading to FPs on > things like pictures of babies. > > http://www.computerworld.com/securitytopics/security/story/0, > 10801,80431p2,00.html > > The reviewer felt that a out of 100 hits, 9 FPs was > acceptable.. In SA terms that's an S/O of 0.91.. While > that's not bad, it's not exactly impressive either, > particularly for something that's likely to be CPU > intensive. The article doesn't describe in detail what the > FN rate is, only uses vague terms.. but it doesn't sound > very good either. > > They also excused FN's on messages containing images made > out of several small images. So right out of the box there's > an evasion technique that spammers can use to avoid this > tool with ease. > > Really, if you're not using razor, you should. It's a better > general-purpose solution for this problem, and likely to run > at about the same speed. > > Razor is able to spam-classify individual mime sections of > messages based on reported SHA hashes. This way if a spam > with that image is reported any other spam with that same > mime section will hit. > > This will also help with the image-based pill spams too, not > just the porn ones. > > > > > > >
