This module stores password hashes securely.
The default password hashes in Drupal 6 (and before) are rather insecure. MD5 is easy to crack, should an attacker find a database dump or gain access to your database. This module implements secure password hashes using the phpass password hashing method - multiple rounds of hashing and salting that make reversing the hash significantly more difficult to break by brute-force attack. This is the same approach that is used for Drupal 7.
The 1.x branches are unsupported.
The 2.x branches feature simplified code and only supports the portable password hashing mechanism backported from Drupal 7 core.
WARNING: after this module is installed and any user password's have been converted, you will not be able to uninstall