Vincent Le Chevalier wrote:
> So, technically you could argue that you're using LZW not to compress, 
> but to obfuscate your data? A slight compression being just a 
> side-effect :-)

Yes, exactly. If, for example, the steps you follow to do LZW compression 
was one step of an encryption algorithm, it wouldn't be encumbered by the 
patent.  Look at the patent:

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=4,558,302.PN.&OS=PN/4,558,302&RS=PN/4,558,302

"""
I claim:

1. In a data compression and data decompression system, compression 
apparatus for compressing a stream of data character signals into a 
compressed stream of code signals, said compression apparatus comprising ...
"""

If you're not compressing data with it, it's not patented. Just like if 
you're not encryption data, modular exponentiation isn't patented.


That patent also patents hardware implementations of LZW. Would you say that 
hardware isn't patentable in the EU, because it's implementing a "software 
patent"?

-- 
   Darren New, San Diego CA, USA (PST)
   Insanity is a small city on the western
   border of the State of Mind.

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