Ciro Santilli 
His standard C header seems to be as per example: www.sqlite.org/src/file/ext/misc/rot13.c
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.