RC2 protected by copyright?

RSA issued a statement claiming that anyone using RC2(TM) would be in
violation of various laws.  I think that they might have a point.

You can't protect an idea with trade secrets, certainly not a software
idea, if you intend to sell the software.  It is easy to reverse
engineer it; this is probably what happened with RC2.

But, what about copyright?   Now, copyrights cannot protect ideas, only
the expression of those ideas.  An algorithm is clearly an idea, you could
write a program that would implement it in a completely different way,
not just by translating it (translations are still protected by
copyright). 

RC2, though, as 256 bytes of seemingly random data at the head of it,
in a permutation table.  This is clearly not any idea, but a bit of
text.  This text would have to be copied to any interoperable RC2.
(You could surely use some different permutation, and probably most
of the 256! permutations would be equally secure, but would not
interoperate with RC2).  I would expect that this copying of text be
held to be a violation of copyright.

Some might argue that 256 bytes is so small that perhaps it couldn't
be copyrighted.  Copyright clearly can't protect use of a word, or
a short phrase (1000 points of light, say).  If the permutation table
at the beginning was 65536 16-bit numbers, instead of 256 bytes, then
the copyright protection be that much stronger and less open to debate.

Do any of the real lawyers on the list want to take a crack at this?
Has anybody heard any noise from RSA describing exactly how they
intend to go after people?

thad
-- Thaddeus Beier                     thad@hammerhead.com
   Technology Development                   408) 286-3376
   Hammerhead Productions        http://www.got.net/~thad

(IANAL, and I'm not even attempting a lay interpretation of the _legal_ 
issues in this message)

thad writes:
> But, what about copyright?   Now, copyrights cannot protect ideas, only
> the expression of those ideas.  An algorithm is clearly an idea, you could
> write a program that would implement it in a completely different way,
> not just by translating it (translations are still protected by
> copyright). 
> 
> RC2, though, as 256 bytes of seemingly random data at the head of it,
> in a permutation table.  This is clearly not any idea, but a bit of
> text.  This text would have to be copied to any interoperable RC2.
> (You could surely use some different permutation, and probably most
> of the 256! permutations would be equally secure, but would not
> interoperate with RC2).  I would expect that this copying of text be
> held to be a violation of copyright.

>From a technical perspective, I can't say that the permutation table is
"clearly not an idea", although that view has some significant allure.
I think many cryptographers would agree that the S boxes in DES represent 
some pretty weighty ideas indeed, and constitute an intrinsic part of the
algorithm. Offhand the precise construction of the RC2 permutation table
doesn't seem to me to be nearly as important to the strength of RC2 as the
S boxes are to DES' strength. I'm certainly no expert. But I'm a little 
hesitant to dismiss the specified table as "a bit of text". 

Do you think the table would be more like an idea if it turned out to be
determined by pi ?  (not a rhetorical question)

-Lewis <lmccarth@cs.umass.edu>		`I went down to the demonstration/ 
to get my fair share of abuse/ singing we're gonna vent our frustration/
if we don't, gonna blow a 50A fuse" -Nanker Phelge

>RC2, though, as 256 bytes of seemingly random data at the head of it,
>in a permutation table.  This is clearly not any idea, but a bit of
>text.  This text would have to be copied to any interoperable RC2.
>(You could surely use some different permutation, and probably most
>of the 256! permutations would be equally secure, but would not
>interoperate with RC2).  I would expect that this copying of text be
>held to be a violation of copyright.

What about "merger"?  If there's only one way to write a table to make it
interoperable, could it be ruled that the idea has merged with its expression
and thus be legal to copy?
--
Ken Arromdee (arromdee@jyusenkyou.cs.jhu.edu, karromde@nyx.cs.du.edu;
    http://www.cs.jhu.edu/~arromdee)

"Snow?" "It's sort of like white, lumpy, rain." --Gilligan's Island