Most devices today come with multiple wireless communication capabilities: WiFi and mobile broadband (3G or LTE) for Internet access, and Bluetooth for connecting to peripherals like headsets, keyboards, and mice, and all of these capabilities have existed for many years. Near Field Communication (NFC) is another form of wireless communication that is slowly appearing on devices, most of which run Android. NFC first appeared in the Samsung Nexus S, and is also available with the Galaxy Nexus and the Nexus 7 tablet. I expect all new smartphones being announced this year to include NFC, so if you buy one later this year or early next you may find you have a device with NFC and wonder how to use it.
One nice thing about NFC is that its name clearly defines the function it provides, unlike WiFi or Bluetooth that provide little insight into the fact they provide Internet access and connection to peripherals. Near Field Communication provides wireless communication between devices that are in close proximity with each other. In fact, it is often the case that for NFC to work the devices must be physically touching. NFC is also capable of reading data stored on relatively small tags that are usually in the form of inexpensive stickers, and as you will see later, software running on devices that support NFC can read and take action on that data.
You might know of a close relative to NFC, RFID, which is commonly used in retail and warehousing to help identify what and how many of a particular product is available. An important difference between RFID and NFC is the distance at which the two work. RFID chips can be read by devices that are as far as a few meters apart, while NFC only transmits as far as 4 inches. The distance limitation of NFC means that in order for it to be used in a hack, it requires near physical contact meaning that if NFC is to be exploited social engineering will be a key component of such an exploit.
To use NFC on my Samsung Galaxy Nexus I first enter the PIN on my phone, then place the back of the phone on a sticker that has information that the phone will read. You hear a sound indicating that NFC is in use, and once the information is read I remove the phone from the sticker. An app on my phone called NFC Task Launcher uses the information to automate a number of different tasks on the phone.
As is the case with any form of wireless communication, it is important to have a basic understanding of how it works to both take advantage of the feature and to protect yourself from those who make want to also take advantage of it to do harm. In the case of NFC one important thing to note is that at least in the case of the Nexus devices running Android NFC is on by default. In my experience the NFC radio has a very low drain on power, but you might wish to turn it off and only turn it on when you want it to be explicitly used.
On Android devices running Ice Cream Sandwich (Android 4.0) or Jelly Bean (Android 4.1), you turn NFC off by going into Settings then selecting More under Wireless and Networks, and tapping the checkbox next to NFC, as shown in the screenshot below.
I have found NFC to be a valuable feature on my mobile devices, and therefore opt to keep the NFC radio on at all times. In another article I will provide specific examples of how I use NFC with my Galaxy Nexus and Nexus 7.