Counterfeiting of manufactured goods is a worldwide problem, with recent studies estimating that 8% of the world's total GDP is now generated by the manufacturing and sales of counterfeit products. Many classes of counterfeit goods create substantial risks to public health including counterfeit pharmaceutical drugs, auto parts, pesticides, and children's toys. In addition, counterfeit computer chips, aerospace parts, and identification documents present significant risks to national security.
Authentication alone is not enough to stop counterfeiting. Counterfeiters use a variety of strategies, including diverting unfinished products from factories that make authentic goods and then adding their own counterfeit brand identifiers such as labels and tags. Counterfeit items can enter the supply chain at any point, including at the original manufacturing facility, at the shipper, in distribution, or in retail stores. Unless the manufacturer or supplier can identify exactly where and when the item entered the supply chain, identifying and eliminating the counterfeit goods can be almost impossible.
Many different approaches have been tried to uniquely identify and authenticate objects, including labeling and tagging strategies using serial numbers, bar codes, holographic labels, RFID tags, and hidden patterns using security inks or special fibers. All of these methods can be duplicated, and many add a substantial extra cost to the production of the goods sought to be protected. Physical labels and tags can also be easily lost, modified, or stolen.