From: James A. Woods >From vn Fri Dec 2 18:05:27 1988 Subject: Re: Looking for C source for RSA Newsgroups: sci.crypt # Illegitimi noncarborundum Patents are a tar pit. A good case can be made that most are just a license to sue, and nothing is illegal until a patent is upheld in court. For example, if you receive netnews by means other than 'nntp', these very words are being modulated by 'compress', a variation on the patented Lempel-Ziv-Welch algorithm. Original Ziv-Lempel is patent number 4,464,650, and the more powerful LZW method is #4,558,302. Yet despite any similarities between 'compress' and LZW (the public-domain 'compress' code was designed and given to the world before the ink on the Welch patent was dry), no attorneys from Sperry (the assignee) have asked you to unplug your Usenet connection. Why? I can't speak for them, but it is possible the claims are too broad, or, just as bad, not broad enough. ('compress' does things not mentioned in the Welch patent.) Maybe they realize that they can commercialize LZW better by selling hardware implementations rather than by licensing software. Again, the LZW software delineated in the patent is *not* the same as that of 'compress'. At any rate, court-tested software patents are a different animal; corporate patents in a portfolio are usually traded like baseball cards to shut out small fry rather than actually be defended before non-technical juries. Perhaps RSA will undergo this test successfully, although the grant to "exclude others from making, using, or selling" the invention would then only apply to the U.S. (witness the Genentech patent of the TPA molecule in the U.S. but struck down in Great Britain as too broad.) The concept is still exotic for those who learned in school the rule of thumb that one may patent "apparatus" but not an "idea". Apparently this all changed in Diamond v. Diehr (1981) when the U. S. Supreme Court reversed itself. Scholars should consult the excellent article in the Washington and Lee Law Review (fall 1984, vol. 41, no. 4) by Anthony and Colwell for a comprehensive survey of an area which will remain murky for some time. Until the dust clears, how you approach ideas which are patented depends on how paranoid you are of a legal onslaught. Arbitrary? Yes. But the patent bar of the CCPA (Court of Customs and Patent Appeals) thanks you for any uncertainty as they, at least, stand to gain from any trouble. =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= From: James A. Woods Subject: Re: Looking for C source for RSA (actually 'compress' patents) In article <2042@eos.UUCP> you write: >The concept is still exotic for those who learned in school the rule of thumb >that one may patent "apparatus" but not an "idea". A rule of thumb that has never been completely valid, as any chemical engineer can tell you. (Chemical processes were among the earliest patents, as I recall.) ah yes -- i date myself when relaying out-of-date advice from elderly attorneys who don't even specialize in patents. one other interesting class of patents include the output of optical lens design programs, which yield formulae which can then fairly directly can be molded into glass. although there are restrictions on patenting equations, the "embedded systems" seem to fly past the legal gauntlets. anyway, I'm still learning about intellectual property law after several conversations from a Unisys (nee sperry) lawyer re 'compress'. it's more complicated than this, but they're letting (oral communication only) software versions of 'compress' slide as far as licensing fees go. this includes 'arc', 'stuffit', and other commercial wrappers for 'compress'. yet they are signing up licensees for hardware chips. Hewlett-Packard supposedly has an active vlsi project, and Unisys has board-level LZW-based tape controllers. (to build LZW into a disk controller would be strange, as you'd have to build in a filesystem too!) it's byzantine that Unisys is in a tiff with HP regarding the patents, after discovering some sort of "compress" button on some HP terminal product. why? well, professor Abraham Lempel jumped from being department chairman of computer science at technion in Israel to sperry (where he got the first patent), but then to work at Hewlett-Packard on sabbatical. the second Welch patent is only weakly derivative of the first, so they want chip licenses and HP relented. however, everyone agrees something like the current Unix implementation is the way to go with software, so HP (and UCB) long ago asked spencer Thomas and i to sign off on copyright permission (although they didn't need to, it being pd). Lempel, HP, and Unisys grumbles they can't make money off the software since a good free implementation (not the best -- i have more ideas!) escaped via Usenet. (Lempel's own pascal code was apparently horribly slow.) i don't follow the IBM 'arc' legal bickering; my impression is that the pc folks are making money off the archiver/wrapper look/feel of the thing [if ms-dos can be said to have a look and feel]. now where is telebit with the compress firmware? in a limbo netherworld, probably, with sperry still welcoming outfits to sign patent licenses, a common tactic to bring other small fry into the fold. the guy who crammed 12-bit compress into the modem there left. also what is transpiring with 'compress' and sys 5 rel 4? beats me, but if sperry got a hold of them on these issues, at&t would likely re-implement another algorithm if they thought 'compress' infringes. needful to say, i don't think it does after the above mentioned legal conversation. my own beliefs on whether algorithms should be patentable at all change with the weather. if the courts finally nail down patent protection for algorithms, academic publication in textbooks will be somewhat at odds with the engineering world, where the textbook codes will simply be a big tease to get money into the patent holder coffers... oh, if you implement LZW from the patent, you won't get good rates because it doesn't mention adaptive table reset, lack thereof being *the* serious deficiency of Thomas' first version. now i know that patent law generally protects against independent re-invention (like the 'xor' hash function pleasantly mentioned in the patent [but not the paper]). but the upshot is that if anyone ever wanted to sue us, we're partially covered with independently-developed twists, plus the fact that some of us work in a bureaucratic morass (as contractor to a public agency in my case). quite a mess, huh? I've wanted to tell someone this stuff for a long time, for posterity if nothing else. james