What are those numbers that come up which you have to copy? (Full Version)

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Giulia -> What are those numbers that come up which you have to copy? (5/5/2008 7:36:56 AM)

What are the bold numbers you have to copy on the net sometimes beofre they allow the post to go up? Is it like saying "have you got your glasses on? Are you drunk or drugged?" or what? like what is the purpose of copying those numbers? If it is to verify your details then it seems silly because even someone who doesn't know you're details can get it if they have their glasses on or aren't drunk or drugged.[:D]



phreddy -> RE: What are those numbers that come up which you have to copy? (5/5/2008 12:17:03 PM)

They are a security device to keep automated spam away.



psaulm119 -> RE: What are those numbers that come up which you have to copy? (5/5/2008 1:41:14 PM)

Giulia, they are called captchas. Am I the only one who thinks there should be a special place in hell for the guy who invented these? I think my successful login for these (the first time) is something between 20 and 40 percent, and Giulia, before you comment, most of the time I'm not drunk or drugged or in need of glasses. [:D]

OK I just found out who to, err, pray for:

The term CAPTCHA (for Completely Automated Turing Test To Tell Computers and Humans Apart) was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford of Carnegie Mellon University. At the time, they developed the first CAPTCHA to be used by Yahoo.

Source: http://www.captcha.net/



PreserveWildlife -> RE: What are those numbers that come up which you have to copy? (5/5/2008 6:51:28 PM)

Many of those human verification systems provide alternate ways of getting the information. Some will switch to an audio format and speak it to you. Captcha isn't so much to prevent spam as much as it is a bot preventer that can catch some spam, automated attacks, dictionary incursions, etc. But they are flawed which is why different places are moving to two-factor authentication and hidden-secret passcodes.



Giulia -> RE: What are those numbers that come up which you have to copy? (5/6/2008 8:23:16 AM)

So, psaulm119 the purpose it's to tell a computer from a human? How curious! What if the computer knows it better than the human?

quote:

in need of glasses


When was the last time you got tested?[:D]



iluvatar -> RE: What are those numbers that come up which you have to copy? (5/6/2008 8:49:56 AM)

quote:

ORIGINAL: Giulia
So, psaulm119 the purpose it's to tell a computer from a human? How curious! What if the computer knows it better than the human?


In some respects, human brains work quite differently from traditional computer programs. Humans are quite good at pattern recognition - recognizing a face or a voice (sometimes too good, when we see things in the clouds); humans are also not very good at long, drawn out computations or keeping track of a lot of numbers at once.

Computer are just the opposite - they seem "smart" because they can solve certain computations quickly, but they're not good at pattern recognition (or at least we humans are not good at defining how to efficiently recognize a pattern and thus, not good at telling the computer how to do it).

Anyways, these "captchas" exploit the fact that computers are not good at identifying patterns by embedding symbols (numbers & letters) into an image, distorting them, and populating the image with noise (lines, dots, shading gradients, etc). For the most part, it's easier for us humans to look at the image and figure out the important parts, but it's much harder for a computer to do that.

-Dan.



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