Captcha’s possible demise good for accessibility?
23rd April 2008 by David North
There has been news lately about Microsoft and GMail Captchas being broken and with figures of 60-80% success rates by spambots is certainly looks like the current method of blocking automated access is going to need a replacement soon.
Now this security image technology has long been the bane of visually impaired users with captchas effectively denying access to large areas of the web. It’s just a small part of the whole accessibility debate.
A new service called IMAGINATION adds another level to the captcha idea and is being touted as captcha 2. IMAGINATION uses a picture of a distorted image and radio button list of options describing the image, these options are also in an image. This would require the recognition of the image and then the text options available which makes things a lot harder for the spambot and unfortunately still keeps the visually impaired out.
I wish I could come up with a solution to this issue but the honest truth is I can’t. Even the odd site that provides an alternative audio captcha isn’t a perfect solution and as voice recognition software is very mature I’m sure that this could be an alternative way in for the spambots.
The only option I can see that satisfies both blocking automated processes and follows accessibility guidelines is the kind of question and response architecture. In it’s simplest form this could be “What is the colour of the sky?” - most users of course will be able to answer “Blue” and be let through. However this does leave the door open to bots being able to lean on the power of the net to answer the questions.
So where to go from here? Well this entire problem stems from the anonymity of the net so the obvious solution is to provide an independently authenticated identification system that could be used in a similar fashion to OpenID.
Being identified on the net solves a wide range of issues being talked about at the moment but are people willing to lose their anonymity though?
I think web developers spend (and in some cases where you see “spend” read “waste”) time developing clever solutions to this problem when putting in place something really simple would do the trick, as in the case you’ve mentioned.
For websites not built on a standard blogging or CMS platform, a simple “please enter the word ‘fish’” would suffice, because spam bot developers aren’t going to take the time to overcome your barrier because your site won’t be that important to them, and you’re not using a system that is implemented across the board (ie: picking your lock will not unlock the doors of other sites).
However if you’re are using a standard platform or you’re writing an app that could potentially be of interest to spam bots, implementing Akismet would do the trick perfectly. There’s already a .NET library for it, and if you’re not happy with that, just use whatever XMLRequest system your platform gives you.
Why is this otherwise-useful post tagged “birminghamuk” and “upyerbrum”?
Hi Andy. I’m based in Birmingham part of the Birmingham Bloggers collective which has various aggregators to pick up these specific tags. I notice you are in Birmingham area too so if you are interested take a look at the Facebook group.
You will probably also be interested in the announcement of the Webvisum plug-in for Firefox: Google Groups
This plug-in is intended to enhance web accessibility; one of its features is Automated and instant CAPTCHA image solving, sign up to web sites and make posts and comments without asking for help! “
Hi Christophe. Very interesting plugin. It really does prove that CAPTCHA is in its final death throes if anyone can download a application that can read them. I just hope that a more accessible alternative becomes a front runner as a replacement.