In the modern world of mass production, many products derive their value from being unique. Special limited edition shoes are sold at incredible prices. Custom paintings and limited edition Blu-ray discs are all sold for a premium precisely because there are so few of them. However, these high markup items quickly lead to counterfeiters. As profit margins increasingly depend on limited editions, the importance of counterfeit protection technology is becoming more and more important.
In recent years, NXP has released a new chip that makes life a lot more difficult for counterfeiters. The new NTAG 424 DNA chip from NXP offers special manufacturers an easy way to prove the authenticity of products. This chip is made possible by many modern advances in NFC technology. Let’s dive a little deeper into this technology to see what makes it tick.
Many people have heard of Radio Frequency Identification (RFID), the technology that enables remote identification of electronic tags attached to objects. However, RFID technology was limited as it only provided a unidirectional communication path. The newer form of this technology is known as NFC or “near field communication”. One common NFC chip that you’ve likely interacted with is the newer tap to pay contactless credit card that doesn’t even need to be inserted. Instead, it uses NFC technology to open a temporary two-way wireless communication channel between the payment system and your card. These devices are powered remotely, which means that the card reader actually powers your card while communicating with it (which is why the card doesn’t need a battery), using essentially the same technology as charging mats or other wireless chargers is used.
The chips that enable NFC are becoming more and more sophisticated. They can store data, run encryption algorithms and of course communicate wirelessly. These skills form the basis of the new anti-counterfeiting technology.
Of course, a unique identifier that identifies a product can be stored on a chip for the entire lifespan of NFC and RFID. However, counterfeiters can steal this data like any other information written on a product. They can copy a serial number and make 1,000 identical products with the same serial number, and they can copy the contents of an NFC chip and make 1,000 identical NFC chips. So how can you use an NFC chip to activate counterfeit protection?
NXP had an interesting idea – what if we could use the data stored on the NFC chip to actively prevent counterfeiting? The idea works like this. Each chip contains not only an identifier, but also a counter for the number of times the chip has been scanned and a chip-specific message authentication key. Scanning the NFC chip provides a link that encrypts the chip ID, the counter and a message authenticator (which uses the chip-specific key). Following the link will take you to a website that will check that the correct key has been used and then check and record the counter. When the counter is on the chip increasingly from the previous scan, then it is counted as a “good” scan and the new counter is recorded. Otherwise it will be counted as a faulty scan and the chip will not be authentic.
To see why this works, let’s assume a forgery operation attempted to duplicate your Super Deluxe widget. They bought the product and it had a chip with ID 1234 and the counter was 1. Let’s say you were able to copy the chip exactly. Since the message authentication keys are chip specific, they cannot create a chip with a different ID as they do not have a key for a different chip. So you are limited to only producing chips with the same ID. However, this also does not work because the counter would not be coordinated. Let’s say you sold three copies of the Super Deluxe widget and they all started with a counter of 1. The first person buys it, scans it successfully and now the counter is 2. The next person buys it and tries to scan it. but since their counter is 1, it now reports an error because the server determines that the counter is not incrementing. Therefore, all subsequent products are known to be counterfeit. Even if the forgery process has coded in each different meter, as soon as several people scan it will quickly be identified as inauthentic because someone else will scan a “later” meter and then the earlier ones will report that they are not authentic on future scans.
This means that a forger is essentially limited to making a single copy of a counterfeit-proof chip before being detected. This technology is fairly new, having only been released for the last four years, and it seems to be fairly slow to adopt, probably due to a lack of understanding of how it works and the lack of tools available to process it. However, as the ecosystem and understanding of this technology (along with the limited edition industry) grows, the use of NFC for anti-counterfeiting is likely to become increasingly commonplace.
