A 'simple' solution is to just supply an audio equivalent. Usually these
are made from several different voices reading the letters over top of
background noise to try and spoil the spammers. Unfortunatley most web
sites assume sighted mouse clickers and fail to provide this
alternative. If you would like to hear an example, give AOL's a try here:
https://new.aol.com/freeaolweb/
Go to the link chooser (VO-U) and follow the link that says "Can't see
this image?" which will pop a new window. In that window activate the
button that says "Play Audio". This will play an audio version of the
same captcha and drop you into the entry form field so you can type it
in. You don't have to actually fill anything else out just to hear how
this works.
That said, the general purpose is to keep automated systems from
creating bogus accounts and using them to send piles of spam or other
bad behavior. The idea is to present some media that is hard to visually
or audibly decipher in hopes that only real humans could get it right.
Of course this is an arms race where the captcha (audio or image) are
trying to keep ahead of the OCR or voice recognition algorithms.
Ultimately this path will end in failure but for the moment it seems to
keep the wolves at bay.
As to how to get other companies to do it right, I dunno. It takes a lot
of work to try and keep ahead of the race so I'm sure AOL, Google and
the like are not going to just give away their secret systems for
generating these things. By definition, if they open sourced it that
would give the spammers insight into how to crack the system. So with no
real sharing in order to support security by obscurity companies are
left trying to create their own systems or buying them from somebody
else, and those are the companies that care. All the others are either
ignorant or just hope the problem will magically fix itself. Not gonna
happen.
Longer term I'm hoping for some of the Open ID stuff to get popular so I
can use an authentication system that works for me and not just the
system built into a particular web site. That still a bit off into the
future though. See
http://openid.net/
CB
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
