Download this mod
The "Overline BBCode" is compatible for both SMF 2.0.X and 1.1.X. It also works on SMF 2.0 RC2.
Adds a [rot13] BBcode to encode content using the rot13 rotation, where A becomes N, B becomes O and so on. Content coded with rot13 becomes readable when re-coded with rot13. It also includes a button that is integrated into the editor.
Install this modification through the package manager. It only edits two files, so nothing should go wrong.
1.1 - 22 October 2009
Update for 2.0 RC2 compatibility
1.0 - 14 August 2009
iKorp Networks - Hosting the modification's demo.
Arantor - Creating the modification.