Download Source to this article

Author: Peter Kellner, 73rd Street Associates
Date: August 20, 2006
Location: San Jose, California USA
Topic: Custom Server Control for CAPTCHA, Part 1 Usage

Background

CAPTCHA stands for (Completely Automated Public Turing test to tell Computers and Humans Apart). The technology was originally developed at Carnegy Mellon University to help tell the difference between a human entering data into a computer system and a machine. The process typically involves showing the user a distorted picture of text and numbers, then the user must interpret this, type what they see into a text field and the computer checks for correctness. Below is a picture of a typical CAPTCHA expression. Wikipedia has a nice definition for CAPTCHA here.

Typical Captcha Image

(more…)