which licence do you use to enforce your wishes?

Copyright is what makes it illegal, not the license. As seen here, Copyright grants the exclusive right to prepare derivative works based upon the copyrighted work. Noone else is allowed to do with without first getting permission (in the form of a license).

Of course, open source licenses allows others to make modifications of the work, though they were often some conditions attached (inclusion of Copyright notice, inclusion of license, publication of the modified work until the same license, etc.