User Login With CAPTCHA Authentication

As of Version 3 DotnetNuke has supported the use of a Captcha image.

Captcha is a method of preventing automated bots from gaining aaccess to web page features, tyically submission forms. An image is presented for the user, with a number of characters. As part of the form completion the user enters the characters shown in the image for verification. The expectation is that automated robots are less able at distinguishing the characters than the human eye. However, some robots are now able to distinguish the characters presented on the simplified forms of the CAPTCHA images. This has lead to the use of more intricate designs, which are not always easy to distinguish the characters, particular problems may exist for the 1 and l. Users with impaired vision may also have trouble completing the form.

It is common for no distinction to be made between upper and lower case characters in CAPTCHA authentication. The DotNetNuke CAPTCHA implementation follows this practice.

To enable the use of the CAPTCHA image select the Security Roles option under the Admin Menu. From the drop down list of actions select User Settings.Near the end of the page, udner the User Account Settings options there are two options assocaited with the use of the CAPTCHA image:

• Use CAPTCHA for Login
• Use CAPTCHA for Registration

Select the options which you wish to use on your website.

NAT January 2007