According to wikipedia,
A CAPTCHA (IPA: /ˈkæptʃə/) is a type of challenge-response test used in computing to ensure that the response is not generated by a computer
which in plain English means that, whenever you want to register with some site or avail its service, the guys who run the site wants to make sure that its you, and that its not a bot(computer program created to automate / impersonate a human accessing that particular site)
Usually, this procedure involves, showing some images containing words in it, and asking the user to type those words. But as computer programs started to imitate these things too(using image recognition software) captchas started becoming more complex.See an example below,
The funny thing about this captcha ( that is posted above) is that, you are supposed to find the letters where a cat is supposedly sitting and type those in a text box. Also while looking at the picture, one wonders whether, it was a 2 or Z, 0 or O and so on. If you get it wrong once, the process repeats again.
While talking about this, I am reminded of a funny cartoon post from geekandpoke.
The make/break world of captchas
You can find a lot of technical aspects of captchas from the wikipedia page. Currently(while you are reading this) a lot of research is still in progress by people who want to break the captchas while another group finds newer and tougher(awkward?)ways to make it harder to break them.
At the end of day, its the end user who is at the receiving end.
A simple search for captcha in google is good read for an afternoon.
Accessibility problems for visually challenged
Captchas also cause serious accessibility problems. Even the audio these sites provide as an alternative is so hard to understand, let alone to make any sense of it(at least for me; but I would urge you to check out some sites for yourself to understand the situation better)
You can find an amazing blog by a visually challenged person at Blind Access Journal. I also came across a Great Accessibility Blog Roundup.
I guess, more research is needed in this area, and I believe all of us CAN contribute to make websites accessible, for all of us. Do post your suggestions and alternatives to captchas in the comment section.
Bye guys.
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I concur! CAPTCHA are becoming a pain in the butt just for humans to read. There are other, more simple ways to check for bots, etc.
One such idea is to start a session for each visitor that contains the unix time stamp that each page was accessed. If the average speed that 5 pages was accessed is less than 2 or 3 seconds, then it might be a bot, so show a temp page where they have to wait.
Or, if over 60 pages are accessed in under 60 seconds.
You get the point.
This is just one idea, but it is possible and seams to me that it would work just fine.
I am a PHP / MySQL developer. Any one have any other ideas I could try? I’ll post source if I do them.
Great post Justin!