Net security purr-fected: Kittens are the unlikely new weapon against online fraud
There’s a new way to combat internet fraud, prevent spam and keep online shopping secure. But your first impressions may be that it’s not exactly high tech. It takes the form of a simple question: from a gallery of fluffy-animal snaps, can you tell which are cats and which are dogs? Your answer is enough to find out whether you are human or an automated spam program, designed to send unwanted email. The dog/cat question is the latest example of a security device called a Captcha, a simple puzzle that usually takes the form of a string of distorted letters and numbers.
http://news.independent.co.uk/sci_tech/article2652498.eceAlso see:
Captchas, online gatekeepers against spam, need an overhaul
Designed to ensure the humanity of Web site users, captchas have grown ever more challenging as online mischief makers design better ways to defeat them.
http://iht.com/articles/2007/06/11/business/codes.php