Adam Laurie lived a few Novembers as a dog earlier this year. By duplicating the RFID tags used to identify pets in the United Kingdom and sewing it into his watch strap, Laurie, an independent security researcher, re-created his dog's ID as a hacking exercise. However, this kind of virtual animal cloning could become a serious issue as industrialized countries roll out RFID-based systems to keep track of their livestock.

Japan and the United Kingdom have led the way, developing so-called source and age-verified tracking systems that could help contain the damage caused by outbreaks of mad cow disease, scrapie, or avian flu. The U.S. Department of Agriculture has also been testing the use of RFID chips as part of a National Animal Identification System.

These systems are changing the way we purchase meat, notes Sue Brown, a product manager with Destron Fearing, a maker of RFID tracking chips. In Japan, consumers can scan a package of beef and have a photo of the people who raised the cow, along with details on how it entered the country, sent to their mobile phones. According to Brown, Destron Fearing has taken steps to prevent its tags from being cloned, including placing the chip in a tamperproof polyurethane casing. "This is an unalterable means of identification," she says.

But not everyone sees the technology as foolproof. Laurie points out that the RFID tags communicate without encryption, so some of them can be cloned or even reprogrammed. "If you create another tag that has the same ID, you can effectively clone the animal." Or at least its identity.

Still, why would someone want to do this? A farmer might want to swap out the identity of a sick animal in his stock to save an entire herd from being destroyed. That's why some companies are starting to match DNA samples with existing ID systems in order to offer a greater level of assurance.

The United States has been lucky so far. There hasn't been an outbreak of mad cow disease like the one that crippled the U.K. beef industry. But that might all change very quickly, says Brown. "We are probably one disaster away from having that sort of thing occur in the U.S."