All stuff I have written (non-commercially) so far has been PD. (Actually I don't even dignify it with a `this is PD' note -- I personally have zip respect for copyright, patents, licenses). Legally, what this means is that your software is copyrighted, and any redistribution of it is illegal. That counterintuitive consequence is the due to a treaty, the Berne Convention, that was designed to cater to copyright owners. However, perhaps one could do one better than PD: restrict use to propogate cypherpunk goals. eg. - You may not use this code in software which provides government back doors. - secret service agencies can not use this software / or must pay exorbitant license fees My information is that such criteria are not legally enforcible under copyright law in many countries. You should probably check with a copyright lawyer before trying such a thing. In addition, a program with a restriction like this is not free software, so people would probably work on a free replacement for it. I don't want government back doors in any software I use, but this kind of restriction is the wrong way to avoid them. The right way is through the GNU GPL, which would enable people to check the source code of a modified version for anything suspicious.