[thelist] force a human intervention requirement for signups or access to resources
David Dorward
david at dorward.me.uk
Wed Feb 11 05:09:44 CST 2004
On 11 Feb 2004, at 10:53, John C Bullas (soton.ac.uk relay) wrote:
> Looking for a way to prevent autosignups to your groups or to prevent
> exploitation of online
> resources by scripts designed to bulk submit?
> Want to challenge visitors to read and type in a graphic of a word
> to gain access to a resource....?
>
<tip type="preventing people using your online resources"
author="David Dorward">
Forcing people to type in the text hidden in a graphic is a good way to
make it impossible for users who can't see graphics (they might be
blind, they might just be using a text browser) to use your site.
What's more, I hear that Porn sites are now trading conversions of
graphics to text for images. So their evilBot gets the graphic, passes
it to the user, finds out the text, signs up to the service and gives
the user porn. So images are no longer an insurmountable barrier to
automated signups.
If you do use an image, make sure there is an alternative way for
people who can't make use of it to sign up.
</tip>
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