Ported from http://code.google.com/p/google-authenticator/
- Fixes an error in the library with the timestamp format.
- Removes original demo app.
- Adds own demo app (auth-demo.php, style.css, dump.sql).
- Adds totp.php to help understand the TOTP algorithm.
This script is discussed in c't Magazin issue 11/2016.
The demo app's user interface is in German. If there's interest I might translate it.