The HTPasswd Sync module let you synchronize a htpasswd and a htgroup file with drupal user database.
The purpose of this module is to let you protect folders outside drupal directory structure with an htaccess file. And then to manage users from Drupal.
The password will be synchronized when the user is created or he changes his password. I will not "guess" password of user allready registered.
Support both standard crypt hashing and crossplatform SHA-1.