Dynamic Access Codes

19 Feb 2006 3:21 PM

Jim

Lately, I've been seeing a lot of those dynamically created access code images
on web forms. You know, some little jpg or gif image that has a random series of
letters and numbers. The form says something to the effect, "Enter the code you
see in the image. This is to protect you from webcrawlers...."

What are these images called? Is there some class in the framework that handles
these?

I did a lot of searching for things like "Dynamic access codes", but I can't
find a definitive name for them. I must be way off base in my searching. Can
anyone help?

Thanks!

20 Feb 2006 10:25 AM

Cor Ligthert [MVP]

Jim,

I don't know what is the name, however if you want to know how to make it
using ASPNET and than just one time.

http://groups.google.com/group/microsoft.public.dotnet.general/msg/3d6b4cadb19ae475

Because that in this way it is nothing for a production environment I have
not set it on our website, mabye I change it completely in the way you want
it and do it than.

Cor

20 Feb 2006 1:55 PM

Cerebrus99

Hi Jim,

I think there are other solutions available for this, rather than
implementing it yourself, I haven't seen any open-source implementations.

I would also be interested to know how they do it. It's seems easy to create
an image by drawing text, but how do they distort the text ???

www.captcha.com provides this explanation of the "Dynamic access codes" :

A CAPTCHATM is a program that can generate and grade tests that most humans
can pass, but current computer programs can't pass. For example, humans can
read distorted text as the one shown below, but current computer programs
can't.

In short, such a code is used to keep out Web-Bots.

Regards,

Cerebrus.

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"Jim" <j**@eank.net> wrote in message news:43F88CDF.8652324B@eank.net...
>
> Lately, I've been seeing a lot of those dynamically created access code
images
> on web forms. You know, some little jpg or gif image that has a random
series of
> letters and numbers. The form says something to the effect, "Enter the
code you
> see in the image. This is to protect you from webcrawlers...."
>
> What are these images called? Is there some class in the framework that
handles
> these?
>
> I did a lot of searching for things like "Dynamic access codes", but I
can't
> find a definitive name for them. I must be way off base in my searching.
Can
> anyone help?
>
> Thanks!
>