Does the GPL allow me to distribute copies under a nondisclosure agreement? (#DoesTheGPLAllowNDA)
No. The GPL says that anyone who receives a copy from you has the right to redistribute copies, modified or not. You are not allowed to distribute the work on any more restrictive basis.
If someone asks you to sign an NDA for receiving GPL-covered software copyrighted by the FSF, please inform us immediately by writing to
[email protected].
If the violation involves GPL-covered code that has some other copyright holder, please inform that copyright holder, just as you would for any other kind of violation of the GPL.
Does the GPL allow me to distribute a modified or beta version under a nondisclosure agreement? (#DoesTheGPLAllowModNDA)
No. The GPL says that your modified versions must carry all the freedoms stated in the GPL. Thus, anyone who receives a copy of your version from you has the right to redistribute copies (modified or not) of that version. You may not distribute any version of the work on a more restrictive basis.