- From: Patrick Lauke <P.H.Lauke@salford.ac.uk>
- Date: Wed, 3 May 2006 11:58:34 +0100
- To: "WAI Interest Group" <w3c-wai-ig@w3.org>
-----Original Message----- From: Matthew Smith [mailto:matt@kbc.net.au] Sent: 03 May 2006 10:47 To: Lauke Patrick Subject: Re: Text-based Captchas Quoth Patrick Lauke at 2006-05-03 18:09... > More generally, users may actually be confused by finding any sort of question > not related to the task they're trying to achieve (I want to book a flight, why is > it asking me who the President of the US is?), so this may require a careful bit of > preamble/legend, perhaps. I agree entirely. My example shows how to use the code - not how it should be implemented. My systems is flawed, but I still regard it as being superior to the "munged" graphics that seem to be in such widespread use. I have very good vision, but I often find graphical Captchas a real pain to read. Implementation of either my, or any other, text-based system should be undertaken with great care and consideration. Firstly, we must be aware that humans, like software, can fail a Turing Test. The questions in my example are a bit tongue-in-cheek and are just that - an example. In a serious implementation, one would consider who would be encountering the Captcha, and tailoring the questions accordingly. Increasing the number of questions will reduce the chance of an "undesirable agent" passing the test, but could, of course, also make it more difficult for our human to get through. There is no reason why one should have to pass all tests - two out of three, for instance, could be acceptable. What I have described is a tool - I know it's a cop-out, but how the tool should be implemented I will leave to others! I should probably add that my preferred technique for confirming bona fides is sending an e-mail with a link that has to be followed. This wouldn't be appropriate for Patrick's example of booking a flight, but if I were establishing identity in that situation, I would probably do my checks by means of a credit card. Some food for thought, anyway. Thanks to Patrick for the feedback. Cheers M -- Matthew Smith IT Consultancy & Web Application Development http://www.kbc.net.au
Received on Wednesday, 3 May 2006 10:58:44 UTC