What is NFC and how does it work?

Surely you have ever seen a passer-by who made a transaction, either in a shop or on a bus or in a restaurant, using his phone or maybe even a smart watch. If you did not understand how this is possible or how he did it, then this is the article for you. For those of you who know what we're talking about, you might be interested in the details of how the aforementioned wireless technology works.

The introduction has already revealed that it is a technology of close communication. It is better known as the NFC function, which is found on many smartphones - even on more low-cost oriented devices. It is also found in tablets, speakers and game consoles such as the Nintendo Switch. Quite a few correlations can be made with other wireless technologies such as Wi-Fi, Bluetooth and ultra-wideband (UWB).

In the following, you will find out how NFC differs from the mentioned technologies and how this useful function actually works, which in recent years has simplified some monotonous tasks.

What is NFC?

Let's start with the basics. Near Field Communication (NFC) is an extremely short-range wireless connection technology that uses magnetic field induction to enable communication between devices when they are touched or brought within a few centimeters. Communication includes, for example, credit card authentication, enabling physical access (to a building, a safe …), transferring small files, quickly launching more powerful wireless connections and quickly connecting to smart devices.

In general, NFC builds on and extends existing ecosystems and standards based on radio frequency identification tags, or RFID. NFC extends RFID and contactless capabilities with more dynamic features enabled by modern smartphones. If the phone does not have NFC connectivity, this is highlighted as a key drawback during (our) tests. With phones that support FNC, we can use mobile wallets such as Apple Pay, Google Pay, NLB Pay, and the like, with which we can take advantage of more billions of RFID tags and terminals worldwide.

NFC facilitates the loading of (payment) cards into the phone for transactions, payment of city transport, access to buildings, even unlocking car doors. Short-range contactless technology also supports interactive capabilities based on the basic functionality of RFID technology, such as automatic pairing with headphones or speakers.

NFC quickly outgrew its original framework

It was originally designed to transfer files between phones using Android Beam wireless communication. For example, Google Nearby Share, which replaced Android Beam, and Huawei Share use NFC to configure wireless services in faster Bluetooth and Wi-Fi networks.

NFC is limited to short-range communication, which has significant security implications. The user must be 10 centimeters or less away from the NFC terminal to process the payment or other communication. Another important aspect is that NFC communication does not require electricity. This allows us to use it in products that do not have a battery, such as credit cards.

We mentioned at the beginning that NFC complements other wireless technologies such as Bluetooth, UWB, Wi-Fi Direct and QR codes. One of the main advantages of NFC is the possibility of establishing a connection extremely quickly, which facilitates the use of IoT devices. For connecting, there is no need to manually validate connections, as is necessary for example with Bluetooth communication. On the other hand, NFC does not shine when maintaining a connection at a distance or for long periods.

How does NFC work?

NFC works with the help of wireless tag readers, cryptographic card processing and P2P (peer-to-peer) connectivity, which it uses for different usage scenarios.

If we use the language of standards, it uses the RFID standards and specifications ISO/IEC 14443 and ISO/IEC 15963. In layman's terms, these standards enable communication using the induction of a magnetic field. For comparison: most radio devices use radio waves to transmit data. NFC transmits data at a frequency of 13.56 MHz.

An important feature of transmission via magnetic induction is that the field disappears much faster than radio waves, which is important from a safety point of view. Thus, for example, there is a smaller possibility that malicious actors can "eavesdrop" on vulnerable transactions (payments, access to buildings...¦).

NFC also includes cryptographic processing of credit cards, which is used for contactless payments. Public key cryptography allows the card to generate a new authentication code for each transaction without revealing the three-digit security code. This guarantees the card owner protection against eavesdropping and interception of signals.

The NFC forum (a non-profit industry association) subsequently added P2P connectivity. Classic scenarios for the use of RFID tags include one-way communication between card readers and RFID tags. The NFC Forum presented specifications that enable smart devices (telephones, headphones, routers, industrial equipment …) to respond to NFC communication. With this, they expanded the capabilities of NFC interaction and connection. At the same time, they were very careful not to jeopardize the existence of security protocols.

How does it compare to Bluetooth and UWB?

One of the biggest advantages of NFC is that it does not require pairing or manual input to establish a connection – pairing takes less than a second. In contrast, Bluetooth devices need to be paired with each other, which is a slightly longer process, but we only do this on the first connection (depending on the device).

NFC is also less energy-consuming than Bluetooth and UWB, as the transmission range is extremely short. When it comes to protecting your smartphone battery, one of the first tips is to turn off Bluetooth. NFC consumes so little power that, for example, iPhone phones use it for emergencies when the phone's battery is almost empty.

Cars are increasingly using UWB for keyless entry, but it is also noticeably more wasteful. UWB is also more expensive, and applications that currently use NFC essentially do not need the positional accuracy that UWB provides.

Does your phone support NFC?

It is increasingly rare to find phones that do not support NFC. Manufacturers consciously decide to remove NFC connectivity for some markets due to lower demand, but this does not apply to Slovenia. If you have a newer Android phone, chances are you have NFC enabled. Go to the quick shortcuts and find the NFC symbol. You can also find the feature in the settings under Connectivity.

Owners of iPhones manufactured after 2015 also have access to this very useful feature.