Re: Linus' sha1 is much faster!

[Nicolas Pitre <nico@cam.org>]

On Mon, 17 Aug 2009, George Spelvin wrote:

> > I don't think this trick of making source code textually different from 
> > another work while still intimately mimicking the same structure entitles 
> > you to any copyright (or non copyright) claims over that other work.  I 
> > certainly wouldn't bet any dime for this standing up in court.  
> 
> <div type="legal digression">
> Actually, I would.  I did a lot more than text search and replace;
> I re-implemented it from FIPS 180-2 (work of U.S. government, no copyright)
> and then merged in the *ideas* from the mailing list.  
> 
> (And from elsewhere; the idea of a five-round macro is from Brian Gladman.)
> 
> Remember, to the extent that something is *functional*, it is not
> copyrightable; copyright only covers the non-functional expressive bits.
> The vast majority of that code is simply required by the standard,
> or the desired calling interface.
> 
> For a large portion of the rest, remember that standard programming
> conventions (e.g.  brace style, macro names IN CAPS, etc.) that's also
> non-copyrightable "scene a faire" material.
> 
> It's well established that paraphrasing a recipe avoids copyright;
> the proportions and treatment of the ingredients is not copyrightable.
> 
> For more details, see the extensive coverage of the NEC v. Intel decision
> (1989) regarding the firmware for NEC's 8086-clone V20 microprocessor.
> It was found non-infringing despite non-clean-room implementation and
> substantial similarities.
> </div>

Whatever.  NEC and Intel were certainly commercial competitors.  They 
were far from being friends.  So if you feel like having too many 
friends then just go ahead with that stance.

> As for politeness, that's exactly why I did post it and solicit
> objections.

You said:

|It uses Linus's and Artur's performance ideas, and some of Linus' macro 
|ideas (in the rotate implementation), but tries to be textually 
|different. Is there anything recognizable that anyone cares to clam 
|copyright to?

the "try to be textually different" in order to ask for "anything 
recognizable that anyone cares to clam copyright to" is what I find 
dubious.

> The purpose of the rewrite is to avoid having to make
> pessimistic assumptions about people who don't respond.
> 
> I suppose I should have made that request clearer:
> Is there anyone who claims copyright on anything here?
> Or would just like credit?
> If so, are you willing to donate it to the public domain?

I think this is much nicer to everyone involved.

As far as I'm concerned, I'm OK with giving any small copyright I might 
have in this SHA1 implementation, if any, to the public domain.  
Credits are always nice.


Nicolas