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Terry Zink's Anti-spam Blog

Protecting your mail from the scum of the internet
A CAPTCHA that beats bots and spammers

A coworker came across the following CAPTCHA.  Finally, one that can beat spammers and their bots!

image

Posted: Monday, October 06, 2008 1:55 AM by tzink
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Comments

JasonG said:

Quite funny but a light went on...

So I thought how about a captcha for a captcha?  The main captcha would be a bit like the above example in the way that it has multiple colors/styles of characters (though a bit less so ;).  Then there would be a second dynamicly generated png/gif/etc... that would tell the viewer to enter the red letters only.

Of course there are other issues (like color blindness) so perhaps the choices would have to be bold/dashed/dotted/slashed/lined-out/etc...

Is it perfect; of course not.  But it would be an order of magnitude tougher for a bot and the original captcha would have to rely less on distortion which would make it easier for humans.

# October 6, 2008 2:02 PM

Ben said:

Why not just have an image with the caption "What kind of animal, (car), (etc) is this?"

# October 6, 2008 2:52 PM

Roland Turner said:

Hey Terry, attribution where it's due: http://ars.userfriendly.org/cartoons/?id=20081005

# October 7, 2008 1:10 AM

kettch said:

@JasonG:

Actually MSR has something similar to that:

http://research.microsoft.com/asirra/?0sr=a

# October 8, 2008 11:24 PM
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