The Captcha Type field set controls what kind of
captcha will be used during account
registration, password recovery, and if a user wants to suggest a url. The choices for captcha are:
- Hash captcha , the user's browser (the user doesn't need to do anything)
needs to extend a random string with additional characters to get a string
whose hash begins with a certain lead set of characters.
- Graphic Captcha , the user needs to enter a sequence of characters from
a distorted image;
Of these, Hash Captcha is probably the least intrusive but requires
Javascript and might run slowly on older browsers.
The graphic captcha is probably the one people are most familiar with.