[License-discuss] Open source license and non disclosure agreement

[Quentin Lefebvre]

Hi,

Currently working on an open source project, we are looking for an 
appropriate license for it.

We would like something that allows us to work with people in a way such 
that :
  - we can be informed of modifications of our program by developers,
  - we can have "our word to say" about redistribution of modified code 
(i.e. we would like to be able to explicitly authorize people to share 
the modified code).

There is something in the GNU (L)GPL in article 2 that looks like what 
we want, but this 2nd article is not so obvious and seems in 
contradiction with others. Here is what is said :

"You may convey covered works to others *for the sole purpose of having 
them make modifications exclusively for you*, or provide you with 
facilities for running those works, provided that you comply with the 
terms of this License in conveying all material for which you do not 
control copyright. Those thus making or running the covered works for 
you must do so exclusively on your behalf, under your direction and 
control, *on terms that prohibit them from making any copies of your 
copyrighted material outside their relationship with you*."

But in GNU GPL's FAQ, here is what we found :
http://www.gnu.org/licenses/gpl-faq.en.html#DoesTheGPLAllowNDA ,
http://www.gnu.org/licenses/gpl-faq.en.html#DoesTheGPLAllowModNDA ,
http://www.gnu.org/licenses/gpl-faq.en.html#DevelopChangesUnderNDA .

I'd be very pleased to have more information and explanations about this 
kind of non disclosure agreement. How is it possible exactly under the 
GPL or LGPL terms ?
Should we maybe choose another license for our purpose ?
Are our goals in total contradiction with open source software ?

Thanks in advance for any suggestion.
Best regards,
Quentin Lefebvre
INRIA
Secure and Mobile Information Systems project