Lyte Byte

You must have come across captcha images while making a comment in blogs or while registering or making a transaction in a secure page. But have you ever wondered why they got the name or who invented it?

For a long time I was thinking CAPTCHA is a twisted form of the word CATCH as what it really does is catching the bots successfully. But that’s not the true story! CAPTCHA is the acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart”.

They are used to tell if the user is an automated system (or bot) or if the user is human. CAPTCHA’s are used to prevent automated software from performing actions that would degrade the quality of a given system, whether due to abuse or resource expenditure.

So Who Invented CAPTCHA?
CAPTCHA was invented and coined at Carnegie Mellon University in 2000 by Luis von Ahn, Manuel Blum, Nicholas Hopper and John Langford. CAPTCHA was first used by Yahoo as a method to fight against SPAM and BOTS.

How does a CAPTCHA work? It involves a computer (the server) asking the user to complete a test, ie. Generating and asking the user to retype the word shown in the image. While the server is capable of generating and grading the test, it will not be able to solve the test on its own (ie, retype the word shown in the image). Thus any user being able to type in the correct text shown is safely assumed to be human.

More information are available at CAPTCHA’s official website.

Also check out more posts on the series, Know A Word