Re: Clipper in patent trouble?

[smb@research.att.com]

	 Even worse, Micali is claiming that his patent on fair cryptosystems
	 (#5,276,737) covers Clipper as well.  In the Wall Street Journal (May
	 31, 1994, p. B6):

	     Mr Micali, whose patent was issued in January, says his patent
	     covers the concept of breaking an encryption key into multiple
	     parts that are guaranteed to work, and are held by escrow
	     agents.

	 It seems to me that Clipper does not guarantee that the multiple parts
	 will work in anywhere near the same way as his scheme does (see my book
	 for details); Clipper is simply a secret splitting scheme.  On the
	 other hand, Micali filed his patent application in Apr 92, a full
	 year before Clipper became public.

I think Micali has a good case.  In patent law, the claims are vital.
Exactly what it is that you're claiming is new is described in the claims;
something infringes if it includes all of the elements of any one claim.
Here's claim 15 of that patent:

	    15. A method, using a cryptosystem, for enabling a
	predetermined entity to monitor communications of users
	suspected of unlawful activities while protecting the privacy
	of law-abiding users, wherein a group of users has a secret
	key, comprising the steps of:

	 breaking the secret key into shares;

	 providing trustees pieces of information that include shares
	 of the secret key; and

	 upon a predetermined request, having the trustees reveal the
	 shares of the secret key of a user suspected of unlawful
	 activity to enable the entity to reconstruct the secret key
	 and monitor communications to the suspect user.

Sure sounds like Clipper to me...  (Claims 1-14 deal with Micali's
major stuff, the ``fair'' public-key based systems.)

If Micali's claim holds up, it provides Cypherpunks with a whole new
weapon against obnoxious cryptographic protocols -- build 'em first,
patent 'em, and *don't* license them to the government...  (Of course,
since the U.S. uses a ``first to invent'' standard, they could defeat
that by opening up secret NSA archives to show that they really had
it first...)

Btw -- I found the patent online via WWW; see http://town.hall.org/
and do the obvious.  If you want just that single patent, go to
ftp://ftp.town.hall.org/patent/data1/05276/05276737, or do the obvious
ftp.