Things you should know about AI,Neural Net,Cryptography.......part 2

In this part i will tell you about a method to fight spam's. This concept is called CAPTCHA(Completely Automated Public Turing Test to Tell Humans and Computers Apart).

This test will tell whether the participant is a human or a machine. i think every one knows about an distorted image whenever you try for registration or try to post some thing on orkut like websites. (Take a look at the image below)
This prevents automated code to register or post. So by this now a days companies are trying to fight spams.

It has many applications also apart from fighting spam.I will write about it in future.