This was discussed at length on the list previously so you might want to
check the archives. That said, it's mainly a cognitive puzzle that tries
to validate that you are a person and not some script trying to gain
access. Visual captchas are usually letter which have been swirled
around with noise to be hard for an OCR program to read and hard for a
real person as well. Audio captchas do similar things to spoken letters.
I suggested before that this is an arms race which will end badly.
Either the captchas will get so hard to discern that people can't get in
or the scammer's algorithms will improve to the point where captchas add
no security. Either way captchas will become useless.
CB
Jude DaShiell wrote:
The purpose of captcha is to make it nearly impossible for sighted
people to log in and impossible for the rest of us.
On Wed, 26 Mar 2008, UCLA Bruins Fan wrote:
Can anyone tell me what the function of CAPTCHAS is supposed to be?
Why are they needed on so many sites? Do they really perform any
function other than making it difficult for blind users to access sites?
Olivia
