Monday, January 30th, 2006 | Geek Stuff


Ever wonder what the deal is with these things are called or whats behind them. Had a friend of mine ping me asking how to get information on them. I know what they’re for – they allow computers to detect whether input is from a human or a computer – humans can read these but computers generally can’t. They deter spammers and other software based attacks from doing things like automatically posting blog comments or applying for email accounts. But I didn’t know what they were called or where they came from and, being the curious fuck that I am, I had to find out… So after some clever dissection of a site that used them (in this case, blogger) I found a term that looked odd to me in the right spot.. A quick google search of that term landed me right where I wanted to be…

So here are the fruits of my labor. From Wikipedia:


A captcha (an acronym for “completely automated public Turing test to tell computers and humans apart”) is a type of challenge-response test used in computing to determine whether or not the user is human

And from the Captcha site:

Telling Humans and Computers Apart


A CAPTCHATM is a program that can generate and grade tests that most humans can pass, but current computer programs can’t pass. For example, humans can read distorted text as the one shown below, but current computer programs can’t:

Sample Nsf

So there it is.. more than you ever wanted to know… 😉

2 Comments to Captcha

January 30, 2006

you always wonder what they are called – thank you for the cool info

January 31, 2006

I love when the word is so distorted you can’t read it.