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Captchas

Written by Alcides Fonseca at 1189435052

Lately I’ve been spammed a lot in this blog, so I decided I had to implement some kind of captcha, a way of checking if it is a real person submitting that form. Here you can check some wicked examples. Through Sérgio I learned about reCaptcha, a project that uses captchas to complement OCR programs. You can read more about this in his post.



I was having some issues trying to implement it, when Bruno Figueiredo told me about Negative Captchas. I googled it and I found out that was a pretty nice system. I added a <input name="email" value="" /> hidden with CSS and changed the email field to “email_alt”. Bots fill all the fields for default, so if the email field has some content, it was a bot since users can’t see it. Easy and users won’t notice.



However, the negative captcha technique has a downside: Spammers can make custom bots to spam the system, but since this is a not-so-popular weblog I’ll take that chance.



Oh and a small time-waster: