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All about CAPTCHAs
The CAPTCHA which I wrote for the comments system on this site turned out to be more troublesome than I thought. Ganeshan made an interesting comment about it earlier — saying that it would keep out spambots as well as those with low IQs! Addition and subtraction were okay, but even I started dreading the multiplication questions, and had Windows Calculator open just in case. Who ever thought multiplying two 2-digit numbers would be such a pain? (I once got a question with an answer that was something like 7378!)
Anyway I've simplified the whole thing now. You'll only get single digit numbers, but to keep things interesting I've made them signed integers.
And don't worry, there won't be any zeroes causing any "division by zero" errors. This also means the numbers aren't truly random, but they get the job done I guess.
Coincidentally, today, Slashdot had this very interesting discussion on CAPTCHAs, with some nice ideas on implementation. I found Tim Tucker's idea of an anti-CAPTCHA very intriguing as well.
Comments for this News Post
$num2 = rand(-9, 9);
if($num1 == 0) ++$num1;
if($num2 == 0) ++$num2;
This is what I did :)
at first i thought it was the word system mama, then i tried to write the answer like "the value of x is 2" but that didnt seem to work :-)
On the last post I had to do 77 *78 ! Not that its hard but I don't want to do that when trying to post a comment :)
Well... its amusing...and incidentally, its also referred to as a MAPTCHA to indicate the mathematics. I think it adds to the flavor and gives the site a more intellectual feel... yay! I agree with Ganesh's feedback... Darwinian selection of the intelligently challenged.
I ran into the same technical issues as you, but my solution is even more simplistic: use only numbers 0-9, don't use division (thus avoiding the notorious DbZ error!) and have the form field accept a max of 2 characters.. I also refrained from verbalizing the formula, instead presenting it as "X # Y = ___" in the ShoutBox form. Since then, I've received no spam! :)
Incidentally, I lay claim to having officially coined the term "MAPTCHA" :) I first edited Wikipedia's "CAPTCHA" entry to casually mention MAPTCHA. Less than 2 weeks later, Google returns one or two results containing the word. Now, as of today, Google returns 14 results! Sneaky, yes. Evil? I don't think so. My apologies to Wikipedia for violating their rules, but technically the present fact invalidates my prior violation.. ^_^
--Weasel
Austin, TX
Dark Fate 2 is a singleplayer level for Doom II, replacing MAP01. It's a small-sized hellish level — and there's a walkthrough video as well.
27-year old Taurean (birthday 15-May-82), Assistant Manager - HR at Tata Consultancy Services Ltd in Hyderabad, India. Previously, did Post Graduate Diploma in Management from T A Pai Management Institute (2003-05) and before that, Computer Science Engineering from Sree Nidhi Institute of Science and Technology (1999-2003).
Email: karthik82 -AT- gmail -DOT- com
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