With MOQCA (also known as MMQPC or Mawan's Moodle Quiz Password Changer), the passwords on quizzes can be changed periodically, automatically. This is useful for preventing examinees from entering and leaving quizzes (eg for cheating on a web browser).

The MOQCA consists of:
1. Android application installed on each exam supervisor's mobile phone.
2. PHP script installed on Moodle server.

Android applications can be downloaded on the Google Play Store:
https://play.google.com/store/apps/details?id=appinventor.ai_mawan911.MMQPC

PHP scripts can be downloaded or cloned from:
https://github.com/mawann/mmqpc/

You may use the MOQCA as much as you like, forever. But there are limitations, namely:
1. Salt cannot be changed, that is, table salt.
2. The replacement duration cannot be changed, which is 5 minutes.

To be able to change the two parameters above, you must register. Instructions for registration can be found on Github.