We loves the way drupal show the password strength meter when user try to register or change their password.

But how about if we want to enforce strict "high" level password rather than suggest as the drupal core password meter?. And how about if we want to check the strength of the password from server side to prevent the low level password to be saved?

The answer for your questions is the Password Strength module. Although in the module page the author initially develop this module to be a password strength meter back port for Drupal 5 but in the end a Drupal 6 version is launched and adds more fine tuning for the password meter and server side validation for the password strength level that we allow for our user to have.

The installation is very easy, you just need to download, unpack and then enable the modules.

The module works by bypassing the password-confirm drupal form element so in theory any module that uses the password-confirm form element can utilize the password strength module validation.

The project page : http://drupal.org/project/password_strength