CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) or HIP (Human Interactive Proof) are often used to reduce email and blog spam and prevent brute-force attacks on web site passwords. Microsoft has researched Asirra, a new Captcha with Pets.
Asirra (Animal Species Image Recognition for Restricting Access) is a HIP that works by asking users to identify photographs of cats and dogs; a task difficult for computers, but easy and accurate for humans.
Asirra has partnered with Petfinder, which provides over two million images of cats and dogs. Assira adds a small “Adopt Me!” link beneath each photo, supporting Petfinder’s primary mission of finding homes for homeless animals.
Check out Â examples of Asirra at work in which you click on all the images that show cats. Learn how to set up Assira on your site and stop spam.