[thelist] Preventing Malicious Login

Steve Clason stevec at topdogstrategy.com
Sat Oct 15 10:10:11 CDT 2005

On 10/15/2005 8:22 AM Tim Burgan wrote:
> Hello,
>   1. What's the name of the image that is generated on some login
>      websites that make the user enter the numbers displayed within the
>      image into a text box?

The technique is generically called CAPTCHA, "Completely Automated 
Public Turing test to tell computers and humans Apart".
>   2. What it is about these images that make image reader software from
>      detecting what's written within the image?

That's the challenge--apparently they aren't 100% successful: 
(scroll down to "Circumvention").

Steve Clason
Web Design and Development
Boulder, Colorado, USA

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