NFC Dual Sensor and Authentication Tag for Spirits, Appliances, Drugs

• Conductive and Capacitive Options
• Tracking Fill Levels and Moisture
• The Next Generation of Security Tags

May 09, 2022NXP Semiconductors has released a new family of Near Field Communication (NFC) integrated circuits (ICs) featuring tamper-detection and condition-monitoring functionality on a single chip. The company's latest chip was designed for use in consumer brands, as well as with healthcare and smart-home products. It includes cryptographic security, in addition to either conductive or capacitive tamper protection, and can be built with capacitive sensing-based moisture, pressure or fill-level detection.

Technology companies are building their own smart labels or sensor devices that could protect high-value wines and spirits, as well as medications, or detect refrigerator leaks. While the tags could verify the authenticity of goods for retailers and consumers, the company says tamper protection offers a digital reassurance that products are properly sealed and have not been opened. Another NXP product, the NTAG 424 DNA, already provides that functionality and has been widely adopted to authenticate and answer the question of whether a product has been opened, according to Christian Lackner, NXP's segment manager for smart products authentication and IoT security.

Lackner says the NTAG 22x DNA family is designed to provide not only tamper detection, but also condition measurements for further insight, using the power of a smartphone's NFC interrogation. The NFC tag, compliant with ISO 14443, offers battery-free sensing and two forms of tamper detection. This allows retailers to, for instance, provide proof that an item—such as a bottle of high-value wine—is genuine and has not been opened, as well as monitor the level of product inside.

Conductive and Capacitive Options

The conductive version leverages a simple conductive loop built into a tagged label that can be affixed, for example, over a closed bottle cap. When the wire in that loop is broken—meaning a cap or lid to which the tag has been applied has been screwed open, or that a box's lid has been opened—that event triggers the writing of an opened status into the chip's memory. The next time a retailer or customer interrogates the tag, the opened status would then be displayed on the user's smartphone.

With capacitive tamper detection, the mechanics are different. The tag's electronics are connected to a capacitive structure, or to electrodes (metal plates) aligned on top of each other. Those applying the tags could set parameters in the NFC tag system relative to the chip's existing capacitive measurements, based on the plates' positions. If a tag has been tampered with, the capacitance has been changed, and the opened status is stored in the chip's memory once the tag is tapped against an NFC phone.

This version of the tag can be more difficult for hackers to reconstruct. While the conductive mode is often best suited for tamper-evident labels and seals affixed to products or their packaging (for which a simple open or closed status would be enough), the capacitive mode is designed for the integration of tags into physical products, and it presents a barrier to fraudulent reconstruction.

Capacitance can enable sensing measurements, such as changes in an item's environmental conditions—moisture, pressure or fill level. When an NFC reader interrogates a sensing tag, the tag harvests the energy from that interrogation to capture data and send it back to a reader. A capacitor can store an electrical charge, which can change if the capacitor plates have moved or been re-positioned, or if the medium between these plates has changed, indicating an opening event, a pressure issue or the presence of moisture. When the a smartphone reads the tag, the mobile application used with that tag can compare the change against preconfigured limits.

NXP expects the product to be used not only for brand authentication and tamper evidence, but also for healthcare, as well as smart-home and retail applications. Use cases include the application of NTAG 22x DNA tags to plaster to detect when it is dry. The tags can measure moisture levels for smart wound care, provide fill-level sensing for smart injectable dosage devices, and offer consumer product refill reminders based on package fill levels.

Tracking Fill Levels and Moisture

Electrodes are built into the tag, running down the side of a bottle and enabling users to view whether that bottle is full, empty or three-quarters filled. The collected data could enable a brand to build a system by which consumers could tap their phone near a product in an opaque bottle to learn how full that bottle is, and they could be prompted to order a refill depending on how much product has been consumed.

With regard to healthcare applications, tags could be applied to liquid medicine bottles or medical supplies for authentication purposes, as well as for tracking the level of medicine. Pharmacies, dispensers or hospitals could use that information to track their use of the product. Users could also verify the fill level of a smart injectable device, such as a syringe, to ensure medication is taken properly.

According to the company, the tags will be used to detect the presence of humidity within an appliance. For instance, a tag applied to a component in a refrigerator could provide users with information on their smartphone if a leakage in the appliance's system occurred. NXP works with partners that would build the label with the sensing functionality, Lackner says, adding, "It gives them a playing field where they can then add their R&D value."

The new IC comes with security features to ensure product authenticity. It provides a 7-byte unique identifier and IC user memory of 144 bytes or 208 bytes. The user memory is protected by a 32-bit password or with mutual authentication via an AES-128 key. Additionally, Lackner says, the NTAG 22x DNA's cryptographically secure authentication message dynamically changes every time a tag is read. That, he explains, helps to make the taps unclonable, without requiring an application on the phone.

Tamper detection is provided with the IC's secure unique NFC (SUN) authentication message feature. SUN authentication automatically adds the UID and tap counter and status, while protecting it with a cryptographic message authentication code to secure its data. Thus, each tap is uniquely authenticated, while its status is protected against fraudulent changes.

The tag leverages 13.56 MHz NFC transmissions compliant with ISO 14443, as opposed to HF technology that transmits according to the ISO 15693 protocol. The NFC transmission can achieve a read distance of up to 10 centimeters (7.5 inches), or a few centimeters with an NFC-enabled smartphone. It provides a benefit over HF RFID, NXP reports, since the latter version, with a longer range, requires greater power. That power demand could affect the response of sensor data.

The Next Generation of Security Tags

The new chips also include security certification via Common Criteria EAL3+, to confirm best efforts were made for customer asset protection. The Common Criteria international standard (ISO/IEC 15408) is used with bank cards and e-ID products to certify security. The chips are commercially available now and solution providers are building products with the chips, some of which their customers are already using. Early deployments are focused on appliances and healthcare products, along with luxury-brand drinks, such as wine and spirits, that require an intelligent enclosure.

NXP says it developed the product as a next generation of security tags following the wide adoption of the NTAG 424 DNA tag. "We are seeing now, from a security perspective, that those products are getting a very high interest" from potential users, Lackner reports. "It's all about brand protection and customer protection," he says. In 2021, for instance, sales growth has been high across NXP's NFC products, but higher for security tags than for standard NFC tags.

With the number of NFC-enabled phones forecasted to reach almost four billion by the end of 2023, Lackner says, half the world's population could eventually have an NFC reader in hand. With the NTAG 22x DNA tag, he adds, "You don't need to install an app on your phone to access the data. The system takes the phone directly to the link. I personally find this is breaking down a big barrier."

Key Takeaways:

• The new tags are designed to provide security and authentication with the added sensor capabilities.
• Companies can use the NTAG 22x DNA tags to capture data about moisture presence on a bandage, the drying status of plaster or an appliance leak.

Exhibitors at RFID Journal LIVE! 2022 will offer a variety of NFC sensor solutions. To learn more, visit the event's website.