DCC is patented

ilo sneak@ipnoc.co.za
Thu Oct 28 06:32:57 UTC 2004

The DCC is based on an idea of Paul Vixie and on fuzzy body matching to
reject spam on a corporate firewall operated by Vernon Schryver starting in
1997. The DCC was designed and written at Rhyolite Software starting in
2000. It has been used in production since the winter of 2000/2001. 

-----Original Message-----
From: dcc-admin@rhyolite.com [mailto:dcc-admin@rhyolite.com] On Behalf Of
John R Levine
Sent: Wednesday, October 27, 2004 7:10 PM
To: Vernon Schryver
Cc: dcc@calcite.rhyolite.com
Subject: DCC is patented

I recently learned about patent 6,330,590.  It was filed in Jan 1999, which
means the work it covers was done in 1998, and fairly broadly covers spam
filtering by counting message signatures.

A PDF copy of the patent is http://www.taugh.com/6330590.pdf

If you haven't read patents before, the first part describes the invention
but isn't legally very important.  The crucial bits are the claims which
start on page 6.  Claims 1 and 2 and claim 30 look a lot like DCC.

Anti-spam vendor Commtouch recently bought the patent:

They say they're going to start selling licenses.  Uh, oh. How long ago did
you start work on DCC?  If it's older than Jan 1998, you're OK.  If not,
this guy probably got there first.

John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for
Dummies", Information Superhighwayman wanna-be, http://iecc.com/johnl, Mayor
"I dropped the toothpaste", said Tom, crestfallenly.
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