Explain that obfs3 improves on obfs2 with a D–H exchange. ([diff](https://trac.torproject.org/projects/tor/wiki/doc/AChildsGardenOfPluggableTransports?action=diff&version=37)) URL: https://trac.torproject.org/projects/tor/wiki/doc/AChildsGardenOfPluggableTransports?version=37