NFC (Near Field Communication)

What is NFC?

Near Field Communication (NFC) is a set of communication protocols built on top of HF RFID at 13.56 MHz. It is defined by the NFC Forum and is designed for very short-range interaction – typically under 5 cm. The key distinction from general HF RFID is that every modern smartphone has an NFC reader, making NFC the only RFID technology that consumers can interact with directly using a device they already own.

NFC is compatible with ISO 14443 (the standard behind contactless payment cards). An NFC-enabled phone can read any ISO 14443 tag, as well as NFC Forum tag types. This backward compatibility means NFC can interact with the billions of contactless cards and tags already deployed.

How it works

NFC operates in three modes:

• Reader/writer mode: The phone acts as an HF RFID reader, powering and reading a passive NFC tag. This is the mode used for tapping smart posters, product authentication tags, and NFC-enabled packaging. The phone provides the RF field; the tag harvests energy and responds.
• Card emulation mode: The phone behaves like a contactless smart card. This is how Apple Pay, Google Pay, and mobile transit cards work – the phone emulates an ISO 14443 card to the payment terminal or turnstile reader.
• Peer-to-peer mode: Two NFC devices exchange data directly. Used for Android Beam (now deprecated) and some file transfer applications. Less common than the other two modes.

NFC Forum tag types

The NFC Forum defines five tag types, each based on an underlying ISO standard:

NDEF (NFC Data Exchange Format)

NDEF is the standard data format for NFC tags. It defines how to store structured records on a tag so that any NFC reader (including phones) can interpret the data. Common NDEF record types include:

• URI record: A URL that the phone opens automatically when tapped. Used for smart posters, marketing, and product links.
• Text record: Plain text in a specified language. Less common than URI records.
• Smart Poster record: Combines a URI with a title and optional icon. The phone can display the title before opening the URL.
• MIME record: Arbitrary data with a MIME type. Used for app-specific payloads like vCards (contact info) or Wi-Fi credentials.
• Android Application Record (AAR): Launches a specific Android app when tapped. If the app is not installed, opens the Play Store.

Phone compatibility

Advantages

• Smartphone readable: The only RFID technology that consumers can use with their own device. No specialist hardware needed.
• Tap-and-go interaction: Intuitive one-tap user experience for payment, authentication, and information access.
• Backward compatible: Works with the billions of existing ISO 14443 contactless cards and readers.
• Security: Type 4 tags (NTAG 424 DNA) support AES-128 authentication with unique cryptographic signatures per tap – extremely difficult to clone.
• Low power: Passive tags require no battery. Phone NFC radios use minimal power.
• Small tags: NFC tags can be as small as 8 mm diameter – suitable for jewellery, wine bottles, and pharmaceutical packaging.

Limitations

• Very short range: Under 5 cm in practice. Requires intentional, close-proximity tap – cannot be used for walk-through portals or bulk reading.
• One tag at a time: NFC reads a single tag per interaction. No bulk inventory capability.
• iOS restrictions: Apple limits card emulation to Apple Pay. Third-party apps cannot emulate arbitrary smart cards on iPhone.
• Metal interference: NFC tags directly on metal surfaces will not work without a ferrite shield or spacer layer.
• No long-range tracking: NFC is a point-of-interaction technology, not a tracking technology. For tracking, UHF RFID is needed.

Common applications

• Contactless payment: Apple Pay, Google Pay, Samsung Pay, and contactless bank cards all use NFC (ISO 14443) for tap-to-pay at terminals worldwide.
• Product authentication: Luxury brands, spirits, and pharmaceuticals use tamper-evident NFC tags with cryptographic verification. Consumers tap to verify authenticity.
• Smart packaging: NFC tags embedded in product packaging link to recipes, instructions, loyalty programmes, or reorder pages. Triggered by a consumer's phone tap.
• Access control: Mobile credentials on phones replace physical access cards. The phone emulates a card to the reader.
• Public transit: Mobile transit passes (Suica, OMNY) use NFC card emulation. The phone acts as the transit card.
• Event tickets: NFC-enabled tickets and wristbands for concerts, festivals, and sports events.
• Device pairing: Tap-to-pair for Bluetooth speakers, headphones, and other peripherals. The NFC tap exchanges pairing information instantly.

NFC vs Bluetooth vs QR codes

Key standards

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