Many sites, for example Skydrive, try to stop robots entering by requiring
you to enter a string of letters which have distorted shapes. I cannot seem to
get it right. Is case important? I cannot distinguish between lower and
uppercase for the letters.
CAPTCHAs case sensitive
Unfortunately, the answer to “does case matter” depends on the site and the technology that they happen to be using to perform this little test.
The test by the way is called a CAPTCHA, a “Completely Automated Program to Tell Computers and Humans Apart.”
The idea is that computers, currently, can’t interpret those pictures and humans are supposed to be able to. The reality is that many of those images are excessively distorted and it can be really hard to tell exactly what those letters are.
Passing the CAPTCHA test
Now, the thing to do in a case like that is – most CAPTCHAs (most that I’ve seen these days) actually have two additional options associated with them.
One is they allow you to say, “I can’t understand this one, give me a different one.” So you can actually cycle through a number of different CAPTCHAs, and based on one that you find you can understand, you can type in the correct response.
The other approach is that most of them have an accessibility option for people that can’t see or can’t see well enough. They will sometimes play an audio CAPTCHA where you simply type in what you hear. That may be an alternative if the CAPTCHA is too difficult for you.
Unfortunately, like I said, the technologies are different depending on what sites you visit. The one that I happen to use on a couple of my other sites is called RECAPTCHA. It’s based on computer technology developed out at Cornell, if I’m not mistaken. It is actually used to perform very slow, massive, digitization of books.
So you’re presented with two words; one of which the CAPTCHA actually knows and you must get right, the other of which the CAPTCHA… well it actually doesn’t know and it’s asking you to express an opinion on just what those letters are. It then takes multiple answers from multiple different people and sort of averages it out. If everybody agrees on what the word is then the CAPTCHA knows that that word from that book is actually this.
So, there you go. I think that the best thing, in general, to do is to try a different CAPTCHA if they give you the option to refresh and if not, give the accessibility options a try to see if that doesn’t get you passed as well.
(Transcript lightly edited for readability.)
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