CAPTCHAs. You've probably seen them. They're those little boxes that show you a picture with some letters and numbers. You're supposed to type those characters in a box to prove that you're a human leaving a comment on a blog post or news website, and not a spambot.CAPTCHA stands for "Completely Automatied Public Turing test to tell Computers and Humans Apart." And since most websites don't have spam filters analogous to the ones that keep your email box (relatively) clean, they seem like a good idea.
Until you see some really poorly produced CAPTCHAs. You know, the kind that are completely impossible to read. Like the one to the right. Or like the 20 or so found on the Headware Blog. Granted, some of these CAPTCHAs aren't so much difficult to read as incredibly inappropriate. But they do show why sometimes automation is not the answer.
[via GHacks]
Reader Comments (Page 1 of 1)
7-30-2007 @ 2:58PM
kingkool68 said...
I got a really weird one from Wikipedia when I tried to register -> http://www.russellheimlich.com/blog/did-wikipedia-just-insult-me/
Also, Security Now episode #101 has some great info about CAPTCHAs including some intelligent methods CAPTCHA breakers are employing to get around the human tests.
http://media.grc.com/sn/SN-101.mp3
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7-30-2007 @ 3:34PM
robot rock said...
I don't remember what site it was, but I recently had to perform basic arithmetic to sign up for some site...
I wish OpenID would take off already!
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7-30-2007 @ 4:05PM
Gil Creque said...
Livejournal's implementation is the worse by far.
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7-31-2007 @ 5:21PM
James said...
Some of these are actually pretty good. Obviously, the ones that are some variation of profanity/crudity are not "good", and ditto with those that are obscured into illegibility. But the photo one ("pick the 3 which are not man made") was designed I believe in a programming contest to come up with new ideas for CAPTCHA systems, and is in fact one of the best tests available. The math problem is a bit much, but some simpler arithmetic ("(4^2 + 2)/3=" or "2X - 3, x=5" or similar) has been used before to great effect, IMHO. I think somebody should make an open-source project to make modular CAPTCHAs so we can get some creative ones into more common use, like those described above.
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