CAPTCHA is actually an acronym for “Completely Automated Public Turing test to tell Computers and Humans Apart”. As the name implies, it is a computer-generated test which aims to separate a bot (automated program) from a live, breathing human being online. The “Turing” refers to Alan Turing, a computer scientist who, in the 1950s, undertook research to distinguish a man from a machine.
source: http://www.tech-faq.com/captcha.shtml
Tags: captcha, validation, validator
