A CAPTCHA system is used by many websites to determine if the user who is accessing the site is human.
This really reduces on the amount of “spam” messages that get sent through online forms.
Unfortunately this system is usually limited to those who have vision as they provide a visual way of accessing site information:
EXAMPLE:
This is totally unreadable by auditory readers.
My co-worker came up with a new way, where auditory readers can still have access to the information on the site while no overly complicating the entrance with a “click here to here a sound” mentality than many sites have gone to.
MATH, now I know that may sound weird, but it really works.
When a bot comes to a site and tries to submit a form and they encounter a simple math question, they can’t do anything.
//HOTSHOT was right, bots can be written for this, I guess this CAPTCHA is really written for a small business that an outside spammer really doesn’t care about writing a specific script for. I wasn’t suggesting for Google or Yahoo to start using this system. But Hotshot, I didn’t think about that to much.
Thanks!
But a human can easily add two numbers together. This method of asking a simple question to determine if a user is human is a very good alternative to elaborate accessibility features. And only requires 2 things.
1. a session to store the number
2. backend to compare it.
I have used this in my contact us section on my home page: ww.x24d.com
HTML:
<label>What is the sum of ?</label>
<input name="cap" type="text" width="20" />
PHP:
<?
session_start();
$num1 = rand(0, 50);
$num2 = rand(0, 50);
$_SESSION['SUM'] = $num1 $num2;
if($_POST['cap'] != $_SESSION['SUM']){
$errors = true;
$_SESSION['SUM'] = ""; //always clear your session so you don't have to worry about re-declaring the wrong number
} else {
$errors = false;
$_SESSION['SUM'] = "";
}
?>
January 20th, 2008 at 1:08 am
thats where you are wrong. cause can identify those numbers and “do math”. captcha works because bots can’t “see or hear”. if its coded the bot can most likely read it. but someone can make a bot with ocr(optical character reader) so they needed to alter the image in a way that it can’t be picked up with ocr, hence the wavy effect and etc.
January 20th, 2008 at 1:09 am
oops
“cause bots can”
November 10th, 2008 at 11:29 am
Just ran across this article and figured you might find interesting my simplistic approach on the captcha matter http://www.vileworks.com/using-captcha-without-displaying-it