Writings

Take THAT, Spammers! » Thu, Nov 2nd 2006 5:55 pm

Due to the growing flood of spam I receive everyday from the forms on this site, I’ve implemented a human-verification tool. It should be familiar to most people: Just type in the letters and numbers you see on the image. Humans can read them, robots cannot. If someone’s built a robot that can, I’ll gladly hear their offer to enlarge my breasts.

It’s designed to be less intrusive than you might think… Once you’ve posted, you’ll see what I mean ;) And by that, I mean you WON’T see… Ooh…

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  1. 1 Tyler on Thu, Nov 2nd 2006 9:00 pm

    A coworker had to implement it into a couple sites at work and I thought the way he was doing it was… well, long and painful.

    I’m interested in how you went about doing it. smiling face

  2. 2 Aaron on Thu, Nov 2nd 2006 9:05 pm

    Well, I used PHP’s GD library to build the image (based on the current time given by the time () function). Then in each form, I have a hidden field called “time” which holds the time, and the image is linked to rimage.php?time=TIME_HERE. I then wrote a simple-to-write, hard-to-crack algorithm for transforming the timestamp into a 5-character string. Then I just ask for someone to type the result of that algorithm into the box. If their typed letters/numbers match the product of running the hidden timestamp variable through the algorithm, then they’re human smiling face

    Probably seems trickier when reading the steps, but it’s pretty simple.

  3. 3 Tyler on Fri, Nov 3rd 2006 11:10 pm

    Right on. Sounds much easier then the way my buddy at work explained it - though he did have to make it with images that were already created.

Feel free to leave some kind of feedback or pose a question. Most links will be parsed on their own, so you can avoid writing <a> tags. I’ve even taken measures to ensure that long links don’t fubar the page layout. Also, you can get fancy with Markdown syntax if you want.

The e-mail address is required to ID you. I’ll keep it secret. I pinky promise.

 
 

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