Most Drupal sites that allow user login are plagued by account requests from abusers and bots whose only intent is to post content to the site for nefarious purposes.
This project provides a simple to use extra hurdle to reduce the bother of spamming account requests. It's primarily useful to sites with a limited target audience (at least for authenticated accounts) where valid users have some side information about the group. The site administrator can define a site-specific "secret word." Anyone requesting an account must enter the secret word before an account is created.
The OTP, One-Time Password, module provides an additional layer of security to the login process by requiring users to enter a randomly generated one-time password in addition to their regular Drup