[Irl-dean] CAPTCHAs

[Joshue O Connor]

Hi Eamon,

> has the list any experiences/thoughts on CAPTCHAs they would like to share?  

For some background have a look at the W3 site [1]. It covers a lot of
areas such as
alternatives like Logic puzzles, Sound output, Limited-use accounts and
Non-interactive checks - as well as non-interactive mechanisms and
alternatives to CAPTCHAs such as Single-sign-on (like MS Passport) and
Biometrics.

IMO CAPTCHAs are often used in the wrong way for the wrong reasons. If
they are being implemented to mostly reduce the amount of spam servers
get then I think better server side controls are a much better solution
- that does not burden the user - until suitable accessible multimodal
interfaces can be developed. Some audio CAPTCHA's are less problematic
however, and I have heard good things about Yahoo and Googles' audio
CAPTCHAs from blind users.

I am - strangely enough - currently doing some user testing for the
Carnegie Mellon University, reCAPTCHA project. [2] Carnegie Mellon
University's computer science department were one of the originators of
the first CAPTCHA (or rather it would be more correct to say the use of
the Turing test in this context).

There is interesting research going into this area about different ways
of checking identity and trust. Gez wrote an interesting article on
Juicy Studio [3] about this and major global companies like THAWTE who
provide secure data encryption services are exploring other models also. [4]

As it stands though CAPTCHAs are, for the short term anyway, here to
stay and the hope is that they will get better and not be a barrier to
access for people with disabilities.

Josh


[1] http://www.w3.org/TR/turingtest/
[2] http://recaptcha.net/
[3] http://juicystudio.com/article/accessibility-of-captcha.php
[4] http://www.thawte.com/secure-email/web-of-trust-wot/index.html

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