JtR core files: copyright issues

Solar Designer solar at openwall.com
Mon Jan 19 03:38:07 UTC 2009

On Sun, Jan 18, 2009 at 06:58:44PM +0100, David Paleino wrote:
> src/x86-64.S:
>   - you state that some functions are based on nonstd.c, others on sboxes.c
>     (both by Matthew Kwan), but don't clearly give a licensing statement.
>     That's your code, your choice to release it under GPLv2 or Matthew-Kwan's
>     micro-license.

Since I don't give a license specifically in that file, it is currently
being licensed under GPLv2 along with the rest of JtR.  Yes, I could
have used Matthew Kwan's micro-license, but I did not.  As you know,
GPLv2 is compatible with it (but far more restrictive), so this
transition is OK.  I see no need to mention the license in that source
file explicitly.

Also, I don't think that I am bound by Matthew Kwan's micro-license
here, as all that I really used was optimized S-box expressions, not
code.  I doubt that optimized versions of boolean expressions,
originally derived from tables in the DES specification, are subject to
copyright at all.  But I am not a lawyer, and luckily this does not
matter this time.

> src/x86-mmx.S
> src/x86-sse.S:
>   - same issue as src/x86-64.S

Same answer.

>   - missing copyright years for authors other than you ;-)

Well, the file I got this from was sboxes-mmx.cpp in a distributed.net
DES client.  It had:

// MMX implementation of Kwan's sboxes
// Bruce Ford <b.ford at qut.edu.au>
// RИmi Guyomarch <rguyom at mail.dotcom.fr>

// $Log: sboxes-mmx.cpp,v $
// Revision 1.5  1998/11/16 15:39:50  remi
// Deleted older sboxes.
// Revision 1.4  1998/09/28 22:09:23  remi
// Cleared 3 warnings.
// Revision 1.3  1998/07/12 05:29:16  fordbr
// Replaced sboxes 1, 2 and 7 with Kwan versions
// Now 1876 kkeys/s on a P5-200MMX
// Revision 1.2  1998/07/08 23:42:28  remi
// Added support for CliIdentifyModules().
// Revision 1.1  1998/07/08 15:43:52  remi
// First integration of the MMX bitslicer.

(I've obfuscated the e-mail addresses in the quote above, although as
far as I'm aware they're non-working anyway.)

So this is 1998, but frankly I am not 100% sure they are the copyright
holders.  As you can see, there was no copyright statement in that
source file.  Maybe there was one on the DES client as a whole, but I'm
not sure I can locate a copy of it now (it does not appear to be
available for download anymore).  Since I doubt that Bruce and Remi ever
transferred their copyright to anyone, such as to distributed.net,
I just assumed that they remained the copyright holders.

I had explicit permission from them to include the code in JtR.

> Also, it would be great if I added mail contacts for Matthew Kwan,

You can find Matthew's e-mail address here:


> Bruce Ford and R??mi Guyomarch

Unfortunately, I completely lost contact with them around Y2K, when I
wanted to transform the "explicit permission" into a specific license.
This bothers me too.  If you manage to contact one or both of them,
please do let me know!



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