The ASP.Net CAPTCHA control
A little while ago, my site was polluted by spam comments on my article pages. I had hoped that since I was just a little guy, my site would escape the crosshairs of the spambots. Colour me wrong.
The de facto standard in preventing spambots from entering comments is to use the Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA). It is a challenge-response test where before a comment may be submitted, the author must correctly enter the text contained in an image. If the author is visually impaired, he may listen to a recorded voice speaking a series of letters and numbers instead.
My gripe, and the reason I originally forewent installing the CAPTCHA control, is that such tests are sometimes difficult to pass. Scroll down to the bottom of this article and see for yourself. The tests need to be difficult to interpret, otherwise spambots will use OCR to derive the message. But I am constantly mistaking some characters for others, and when the text is warped, overlapping and struckthrough, I find it sometimes impossible to read.
I have also found the audio CAPTCHAs to be difficult to understand. They usually contain a lot of background noise to foil spambots. Depressingly, computers have more success in understanding audio CAPTCHAs than I do.
Finally, the implementation is not XHTML compliant. I may eventually see if I can
fiddle with the rendering to produce a more compliant implementation.
My site has not been spammed since I installed the ASP.Net CAPTCHA control. I hate the thought of my site being more difficult to use, but it appears to be
a necessary compromise.
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