Free user authentication/password protection system in PHP

Deadlock is a free, open source (licensed under the GNU GPL.) user authentication/password protection system written in PHP/MySQL. It uses .htpasswd and .htaccess files to protect any web directory.

Features:

• Administration Panel
  All settings and administrative controls are in the admin panel.
• User Panel
  Gives users the ability to change their password, email address, and any other account information
• Admin Approval
  When this option is enabled, the administrator must approve accounts before they are able to login to the protected area.
• User Email Verification
  Users are sent a confirmation email to the address specified and must click the link in the email to verify that the email provided is their email.
• Multiple Authentication Types
  The administrator has the option to choose between Basic and Digest authentication.
• Auto htpasswd generation
  Automatically generates the .htpasswd file containing the users when a new user is added.
• Auto htaccess generation
  Automatically generates the .htaccess file when the name of the protected area is changed.
• Templatable user panel pages
  The user panel pages are generated with a template engine, allowing you to customize the pages that the user sees by simply editing the html templates.
• Templatable System Emails
  Customize system emails by editing the templates. Deadlock does not yet include an editor in the admin panel.
• Web based configuration
  Configuration options can easily be modified through the administration panel.
• Integrated Email Functionality
  Specific users can be emailed straight through the admin panel, by simply selecting a link.
• Bulk Email all registered users
  Includes bulk email functionality allowing you to email everyone in the database.
• Search through user list
  The user list is searchable, allowing you to find a user's account by just entering their last name, first name or username.
• Rollover Information
  Rollover information boxes are provided throughout Deadlock which give an explanation of each feature and option.