PAM module to check password strength

 libpwquality's purpose is to provide common functions for password
 quality checking and also scoring them based on their apparent randomness. The
 library also provides a function for generating random passwords with good
 pronounceability.
 .
 This module can be plugged into the password stack of a given service to
 provide some plug-in strength-checking for passwords. The code was originaly
 based on pam_cracklib module and the module is backwards compatible with its
 options.