what is this?

[the.kaushik]

when we register, or say in rapidshare while we want to download anything we are told to verify by typing a auto generated code.. can anyone say what is that called.. ie. any special term for that.. also how is it possible to give such option in our own website???

[ravi_9793]

this is used to stop spam.
By this they unsure that...the work is done manuallly ,not by any software.

Yes,you can have this in ur website also.Most of the php script(CMS,forum,blog) comes with this feature.

[Manshahia]

the term is i think cryptography....
suppose u hav a web site and its without that protection and spammers want to make it bad with spamming...
they will just create a software which will automatically start creating user accounts on its own...
Otherwise if u hav that protection then the software wont b able to recognise that picture on its own.. this needs a human being..

[Sukhdeep Singh]

Its called CAPTCHA

A CAPTCHA (an initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart", trademarked by Carnegie Mellon University) is a type of challenge-response test used in computing to determine whether or not the user is human. The term was coined in 2000 by Luis von Ahn, Manuel Blum, Nicholas J. Hopper of Carnegie Mellon University, and John Langford of IBM. A common type of CAPTCHA requires that the user type the letters of a distorted image, sometimes with the addition of an obscured sequence of letters or digits that appears on the screen.


This somewhat more sophisticated CAPTCHA of "wikipedia" adds more distortions as well as highlights, shadows, and random line segments to thwart edge detection.


Because the test is administered by a computer, in contrast to the standard Turing test that is administered by a human, a CAPTCHA is sometimes described as a reverse Turing test, although this term is ambiguous because it could also mean a Turing test in which the participants are both attempting to prove they are the computer.

http://en.wikipedia.org/wiki/Captcha
http://www.captcha.net/

[Dharmpal Singh]

Originally Posted by ravi_9793

this is used to stop spam.
By this they unsure that...the work is done manuallly ,not by any software.

Yes,you can have this in ur website also.Most of the php script(CMS,forum,blog) comes with this feature.

Yes this is right reason

[kerthivasan]

the term is cryptography and this method is employed to stop spamming as said by others

[The Unknown]

Originally Posted by Siddharth Maheshwari

In which language you want to make it?

any scripting language. Called CAPTCHA. www.captcha.net

[Cool G5]

Yes it is implemented to stop spamming.

[the.kaushik]

Originally Posted by sukhdeepsinghkohli

Its called CAPTCHA



http://en.wikipedia.org/wiki/Captcha
http://www.captcha.net/

superb.. thanx..thats the info i want.. a rep to u