CAPTCHA - Completely Automated Public Turing Test To Tell Computers and Humans Apart
Developed primarily to stop automated processes from submitting form data through scripts. Essentially ensuring that data in a form is verified before sending by having the sender input a randomly generated series of characters which cannot be read by a programme or automated scripts.
This is invaluable when it comes to web site forms and helping to reduce (probably not stop completely!) spam and generally annoying robots!
Although not the prettiest captcha you will have seen on the internet what I like about this captcha is that it's totally independent of any secondary host or provider. Just hook the script up to your page and its done! It works in exactly the same way but uses asp to draw the bitmap and add the text - all done by script.
script developed from the resources at www.tipstricks.org/
other resources on captcha can be found at www.captcha.net
