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Block Spam Bots With Free CAPTCHA Service

Posted by timothy on from the screwtape-and-pals-shriek dept.

Chirag Mehta writes "I just released a freeware service called BotBlock (barebones demo) that lets site owners copy/paste a few lines of PHP code and insert a CAPTCHA image-verification system into any web form. The amount of form spamming by bots is on a rise. While remedies exist for MT blogs, a more efficient solution is to use image-verification or text-identification. Used for a while by sites like Yahoo! (scroll to bottom), Hotmail and patented in 2001 by AltaVista, CAPTCHAs are now being used more widely. PARC also came up with two algorithms Baffletext and Pessimal Print. The technology always existed, but until now required the site owners to install image libraries and understand how to generate images that cannot be OCR'ed. With BotBlock it is like inserting a page counter."

3 of 56 comments (clear)

  1. What about blind people? by FattMattP · · Score: 4, Interesting

    What about people who are blind or visually impared? Does your implementation take that into account?

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    Prevent email address forgery. Publish SPF records for y
    1. Re:What about blind people? by Glass+of+Water · · Score: 5, Interesting
      What they should do is use a question, written out in regular HTML text that is easy for a human to answer but hard for a computer. Example: What color is the sky on a cloudless day? Another example: My name is Joe Frank Smith. What are my initials?

      Think those are easy for basic AI bots? Then try them with one of the existing online bots.

      Seems like the problem with this (as opposed to generating pictures) is that it's hard to generate question/answer pairs where there is a one-word or obvious single answer. You don't want to use yes/no questions or questions where the answer is a word in the question ("Which is heavier, lead or cotton?").

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      There are no trolls. There are no trees out here.
    2. Re:What about blind people? by herrvinny · · Score: 4, Insightful

      The problem is, generating all those sentences. The sentences have to vary, they can't all be: My name is Barney Big Purple Dinosaur. What are my initials? My name is Einstein Mozart Bach Quartet. What are my initials? Then a spammer could just use regular expressions to handle that. Even Java introduced an easy-to-use regex package a few versions ago. Another problem is, you would have to generate literally billions of them, because a spammer may theoretically just hit a service with billions of requests - who's to say that the requests are real or not? And then the ultimate problem: How are we going to generate all these questions? A computer, of course, but the problem is again, how does a computer generate billions of these things so only a human and not a computer can interpret it? At that point, you're approaching true AI. And if we had AI, forget the spam problem: Just have the AI process each and every email.