For those customers who do care, it is worth protecting their investment.

Public-key encryption is a widely used and accepted method for securing communications and while the concept cannot be applied directly, a similar model can be used to insure an item's authenticity. Since objects in the physical world cannot be decrypted per se, if we use unique TAGs we can make a functional comparison.

Instead of being caught up in an argument over what constitutes private and public keys, consider a model where TAGs can either carry the information that would make up a given key or can link to that information. The roles of the keys may be reversed so we leave it to the reader to determine if the model meets the requirements.

Consider how TAG can be used effectively as an authentication mechanism to combat counterfeiting of high-end goods. In our example, a manufacturer would apply a unique TAG to every product they ship and issue a second unique TAG to all authorized retailers. These second TAGs would be made visible to the public and could be considered as the public component of the system.

As customers enter the store they could scan the retailer's public TAG and as they subsequently scan each item's TAG the information from both would be sent to an online service operated by the manufacturer or a 3rd party. Once compared by the service, the result is returned to the customer, validating the goods. That is straightforward; however, since the physical TAGs could be copied, would it be effective?

Counterfeiters could still copy a product's TAG but since they are unique, they would have to copy each TAG on every product, which by itself is a significant deterrent. Assuming, they are able to copy the product's TAG, they would then have to copy the retailer's TAG as well and that could be extremely difficult, especially if the retailer's TAG were also customized graphically to contain the retailer's logo or other identifying marks. Alternatively, the retailer TAG could be time-stamped or could it could be regenerated at regular intervals. Additionally, every item's TAG can point to information associated with the public TAG and can be changed randomly. The point is there are a number of different strategies that can be employed to prevent spoofing, without simply relying on the uniqueness of TAGs.

One reason that TAG is so well suited to providing an effective solution is that unlike other 2D barcodes, TAGs can be designed with a specified duration. While this was intended to facilitate advertising campaign management it allows TAGs to be activated and deactivated at will. In addition, since TAGs are only a link to the actual keys, neither is exposed and reconciliation can take place in the system not on the phone or at a counterfeiter's spoofed location.

Another reason that TAG is the best choice for this is because unique TAGs can be produced in mass quantities programmatically and therefore be integrated into a manufacturer's existing processes. This makes it a cost-effective solution in addition to all else. The ability to expire a TAG means that authorization can be revoked and therefore after an item has been sold the TAG can be expired, as a part of a registration process, for instance. If a shipment were lost or stolen, a manufacturer could expire the TAG immediately. Better still, they can change the functionality invoked by the TAG to alert law enforcement to aid in apprehension or recovery.

Ultimately, the amount of security will be dictated by necessity. Just applying a unique TAG may be sufficient by itself. In other cases multiple TAGs and extensive behind the scenes strategies can be employed. At a point in the future, this could be extended to all goods and services. It seems like it would fit nicely into a business model like the one VeriSign has in place.

Since the actual TAGs are unique and therefore costly to counterfeit, their uniqueness makes them a perfect choice to add security to various different products and activities. Once you generate a specific TAG, no one else can duplicate the TAG in the system, nor does anyone else have access to the TAG in the system, so the only thing that someone can do is reprint it. In a different example, if you passed a course or got a degree, a TAG could be added to the paper document as a measure of authenticity. All it does is link to an account in the system that is controlled by the issuer but since no one else can access you can be sure that the corresponding information is true.

With all this going on, as far as the customer and retailer are concerned the process remains seamless and straightforward. Scan the retailers TAG. Then scan any TAG in the store to get confirmation that what you are about to buy is "the real McCoy".