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Near-Field (or nearfield) communication (NFC) is a form of short-range wireless communication where: 1) The antenna is much smaller than the wavelength of the carrier signal, thus preventing a standing wave from developing within the antenna, and so in the near-field (there is no universally accepted definition of the length of the nearfield  but for practical purposes one can assume it is roughly one quarter of a wavelength) the antenna can produce either an electric field, or a magnetic field, but not an electomagnetic field, and 2) The receiver is within the transmitters near field. Thus NFC communicates either by a modulated electric field, or a modulated magnetic field, but not by radio (electromagnetic waves). For example, a small loop antenna (also known as a magnetic loop) produces a magnetic field, which can then be picked up by another small loop antenna, if it is near enough.
Magnetic NFC has a useful property of being able to penetrate conductors that would reflect radio waves. For example, magnetic NFC was once used for communicating with submarines while they are submerged because the magnetic flux lines can penetrate conductive sea water. But in this case the frequency had to be extremly low in order to make the wavelength long enough (hundreds of miles) to be useful for submarines.
Some mobile phones now use electric-field NFC (operating at a frequency of 13.56 MHz, corresponding to a wavelength of 22.11 m) for certain special transactions because the very short range of NFC makes it difficult to eavesdrop on. To efficiently generate a far-field, which means to send out radio waves of this wavelength, one typically needs an antenna of a quarter wavelength, in practice a metre or more. If the antenna is just a few centimetres long, it will only set up the so-called ‘near-field’ around itself, with length, width and depth of the field roughly the same as the dimensions of the antenna. Very little energy will radiate away, it is essentially a stationary electromagnetic field pulsating at 13.56 MHz. If you bring another similarly small antenna into this field, you will induce an electric potential into it, alternating at the said frequency. By modulating the signal in the active antenna, one can of course transmit a signal to the passive, receiving antenna. Present and anticipated applications include contactless transactions, data exchange, and simplified setup of more complex communications such as Wi-Fi. Communication is also possible between an NFC device and an unpowered NFC chip, called a "tag".
NFC builds upon RFID systems by allowing two-way communication between endpoints, where earlier systems such as contactless smart cards were one-way only. It has been used in devices such as Google Nexus since the Nexus S, but wasn't really used until Android 4.0 Ice Cream Sandwich was released with a feature called "Android Beam" which was first introduced with the Galaxy Nexus.
Since unpowered NFC "tags" can also be read by NFC devices, it is also capable of replacing earlier one-way applications.
NFC devices can be used in contactless payment systems, similar to those currently used in credit cards and electronic ticket smartcards, and allow mobile payment to replace or supplement these systems.
With the release of Android 4.4, Google introduced a new platform support for secure NFC-based transactions through Host Card Emulation (HCE), for payments, loyalty programs, card access, transit passes, and other custom services. With HCE, any app on an Android 4.4 device can emulate an NFC smart card, letting users tap to initiate transactions with an app of their choice. Apps can also use a new Reader Mode so as to act as readers for HCE cards and other NFC-based transactions.
NFC offers a low-speed connection with extremely simple setup, and can be used to bootstrap more capable wireless connections. For example, the Android Beam software uses NFC to complete the steps of enabling, pairing and establishing a Bluetooth connection when doing a file transfer, disabling Bluetooth automatically on both devices once the desired task has completed. Nokia, Samsung, BlackBerry and Sony have used NFC technology to pair Bluetooth headsets, media players, and speakers with one tap in its NFC-enabled devices. The same principle can be applied to the configuration of Wi-Fi networks. This only works between Android devices version Jelly Bean and above. Samsung Galaxy devices have a feature named S-Beam, an extension of Android Beam that uses NFC (to share MAC Address and IP addresses) and then uses WiFi Direct to share files and documents. The advantage of using WiFi Direct over Bluetooth is that it permits much faster data transfers, having a speed of up to 300Mbit/s for sharing large files.
The NFC Forum promotes the potential for NFC-enabled devices to act as electronic identity documents and keycards. As NFC has a short range and supports encryption, it may be more suitable than earlier, less private RFID systems.
Smartphones equipped with NFC can be paired with NFC Tags or stickers which can be programmed by NFC apps to automate tasks. These programs can allow for a change of phone settings, a text to be created and sent, an app to be launched, or any number of commands to be executed, limited only by the NFC app and other apps on the smartphone.
These applications are perhaps the most practical current uses for NFC since it does not rely on a company or manufacturer but can be utilized immediately by anyone anywhere with an NFC-equipped smartphone and an NFC tag.
NFC has been used in video games starting with Skylanders: Spyro's Adventure. With it you buy figurines which are customizable and contain personal data with each figure, so no two figures are exactly alike. The Wii U is the first system to include NFC technology out of the box.
NFC traces its roots back to radio-frequency identification, or RFID. RFID allows a reader to send radio waves to a passive electronic tag for identification, authentication and tracking.
NFC standards cover communications protocols and data exchange formats, and are based on existing radio-frequency identification (RFID) standards including ISO/IEC 14443 and FeliCa. The standards include ISO/IEC 18092 and those defined by the NFC Forum, which was founded in 2004 by Nokia, Philips Semiconductors (became NXP Semiconductors since 2006) and Sony, and now has more than 160 members.The Forum also promotes NFC and certifies device compliance and whether it fits the criteria for being considered a personal area network. In addition to the NFC Forum, the GSMA has also worked to define a platform for the deployment of "GSMA NFC Standards". within mobile handsets. GSMA's efforts include "Trusted Services Manager"., Single Wire Protocol, testing and certification, "secure element".. The GSMA standards surrounding the deployment of NFC protocols (governed by the NFC Forum) on mobile handsets are neither exclusive nor universally accepted. For example, Google's deployment of Host Card Emulation on Android KitKat provides for software control of a universal radio. In this "HCE Deployment"., the NFC protocol is leveraged without the GSMA standards.
|Computer network types|
by spatial scope
NFC is a set of short-range wireless technologies, typically requiring a distance of 10 cm or less. NFC operates at 13.56 MHz on ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to 424 kbit/s. NFC always involves an initiator and a target; the initiator actively generates an RF field that can power a passive target. This enables NFC targets to take very simple form factors such as tags, stickers, key fobs, or cards that do not require batteries. NFC peer-to-peer communication is possible, provided both devices are powered. A patent licensing program for NFC is currently under deployment by France Brevets, a patent fund created in 2011. The program under development by Via Licensing Corporation, an independent subsidiary of Dolby Laboratories, terminated in May 2012. A public, platform-independent NFC library is released under the free GNU Lesser General Public License by the name libnfc.
NFC tags contain data and are typically read-only, but may be rewriteable. They can be custom-encoded by their manufacturers or use the specifications provided by the NFC Forum, an industry association charged with promoting the technology and setting key standards. The tags can securely store personal data such as debit and credit card information, loyalty program data, PINs and networking contacts, among other information. The NFC Forum defines four types of tags that provide different communication speeds and capabilities in terms of configurability, memory, security, data retention and write endurance. Tags currently offer between 96 and 4,096 bytes of memory.
|Speed||Active device||Passive device|
|424 kbit/s||Man, 10% ASK||Man, 10% ASK|
|212 kbit/s||Man, 10% ASK||Man, 10% ASK|
|106 kbit/s||Modified Miller, 100% ASK||Man, 10% ASK|
|Aspect||NFC||Bluetooth||Bluetooth Low Energy|
|Tag requires power||No||Yes||Yes|
|Cost of Tag||10c||$5||$5|
|RFID compatible||ISO 18000-3||active||active|
|Standardisation body||ISO/IEC||Bluetooth SIG||Bluetooth SIG|
|Network Standard||ISO 13157 etc.||IEEE 802.15.1||IEEE 802.15.1|
|Cryptography||not with RFID||available||available|
|Range||< 0.2 m||~100 m (class 1)||~50 m|
|Frequency||13.56 MHz||2.4–2.5 GHz||2.4–2.5 GHz|
|Bit rate||424 kbit/s||2.1 Mbit/s||1 Mbit/s|
|Set-up time||< 0.1 s||< 6 s||< 0.006 s|
|Power consumption||< 15mA (read)||varies with class||< 15 mA (read and transmit)|
NFC and Bluetooth are both short-range communication technologies that are integrated into mobile phones. As described in technical detail above, NFC operates at slower speeds than Bluetooth, but consumes far less power and doesn't require pairing.
NFC sets up more quickly than standard Bluetooth, but has a lower transfer rate than Bluetooth low energy. With NFC, instead of performing manual configurations to identify devices, the connection between two NFC devices is automatically established quickly: in less than a tenth of a second. The maximum data transfer rate of NFC (424 kbit/s) is slower than that of Bluetooth V2.1 (2.1 Mbit/s).
With a maximum working distance of less than 20 cm, NFC has a shorter range, which reduces the likelihood of unwanted interception. That makes NFC particularly suitable for crowded areas where correlating a signal with its transmitting physical device (and by extension, its user) becomes difficult.
In contrast to Bluetooth, NFC is compatible with existing passive RFID (13.56 MHz ISO/IEC 18000-3) infrastructures. NFC requires comparatively low power, similar to the Bluetooth V4.0 low energy protocol. When NFC works with an unpowered device (e.g., on a phone that may be turned off, a contactless smart credit card, a smart poster), however, the NFC power consumption is greater than that of Bluetooth V4.0 Low Energy, since illuminating the passive tag needs extra power.
NFC is an open platform technology standardized in ECMA-340 and ISO/IEC 18092. These standards specify the modulation schemes, coding, transfer speeds and frame format of the RF interface of NFC devices, as well as initialization schemes and conditions required for data collision-control during initialization for both passive and active NFC modes. Furthermore, they also define the transport protocol, including protocol activation and data-exchange methods. The air interface for NFC is standardized in:
NFC incorporates a variety of existing standards including ISO/IEC 14443 both Type A and Type B, and FeliCa. NFC enabled phones work basically, at least, with existing readers. Especially in "card emulation mode" an NFC device should transmit, at a minimum, a unique ID number to an existing reader. In addition, the NFC Forum has defined a common data format called NFC Data Exchange Format (NDEF), which can store and transport various kinds of items, ranging from any MIME-typed object to ultra-short RTD-documents, such as URLs. The NFC Forum added the Simple NDEF Exchange Protocol to the spec that allows sending and receiving messages between two NFC-enabled devices.
The GSM Association (GSMA) is the global trade association representing nearly 800 mobile phone operators and more than 200 product and service companies across 219 countries. Many of its members have led NFC trials around the World and are now preparing services for commercial launch.
GSM is involved with several initiatives:
StoLPaN ('Store Logistics and Payment with NFC') is a pan-European consortium supported by the European Commission's Information Society Technologies program. StoLPaN will examine the as yet untapped potential for the new kind of local wireless interface, NFC and mobile communication.
The NFC Forum is a non-profit industry association formed on March 18, 2004, by NXP Semiconductors, Sony and Nokia to advance the use of NFC short-range wireless interaction in consumer electronics, mobile devices and PCs. The NFC Forum promotes implementation and standardization of NFC technology to ensure interoperability between devices and services. As of June 2013, the NFC Forum had over 190 member companies.
To realize the benefits of NFC in cellphones not yet equipped with built in NFC chips a new line of complementary devices were created. MicroSD and UICC SIM cards were developed to incorporate industry standard contactless smartcard chips with ISO14443 interface, with or without built-in antenna. The microSD and SIM form factors with built-in antenna have the great potential as bridge devices to shorten the time to market of contactless payment and couponing applications, while the built in NFC controllers gain enough market share.
Other standardization bodies that are involved in NFC include:
A growing number of online communities and open source projects contribute to the growth of NFC. Projects range from full NFC stacks to NFC message composition and platform-specific tools.
|This article's Criticism or Controversy section may compromise the article's neutral point of view of the subject. (August 2014)|
Although the communication range of NFC is limited to a few centimeters, NFC alone does not ensure secure communications. In 2006, Ernst Haselsteiner and Klemens Breitfuß described different possible types of attacks, and detail how to leverage NFC's resistance to man-in-the-middle attacks to establish a specific key. Unfortunately, as this technique is not part of the ISO standard, NFC offers no protection against eavesdropping and can be vulnerable to data modifications. Applications may use higher-layer cryptographic protocols (e.g., SSL) to establish a secure channel.
The RF signal for the wireless data transfer can be picked up with antennas. The distance from which an attacker is able to eavesdrop the RF signal depends on numerous parameters, but is typically a small number of metres. Also, eavesdropping is highly affected by the communication mode. A passive device that doesn't generate its own RF field is much harder to eavesdrop on than an active device. An attacker can typically eavesdrop within 10m and 1m for active devices and passive devices, respectively.
Because NFC devices usually include ISO/IEC 14443 protocols, the relay attacks described are also feasible on NFC. For this attack the adversary has to forward the request of the reader to the victim and relay back its answer to the reader in real time, in order to carry out a task pretending to be the owner of the victim's smart card. This is similar to a man-in-the-middle attack. For more information see a survey of practical relay attack concepts. One of libnfc code examples demonstrates a relay attack using only two stock commercial NFC devices. It has also been shown that this attack can be practically implemented using only two NFC-enabled mobile phones.
In 2011, handset vendors released more than 40 NFC-enabled handsets. The iPhone 6 line will be the first handsets from Apple to support NFC, and will use Apple Pay for payment services. Google also includes NFC functionality in its Android mobile operating system and provides an NFC payment service, Google Wallet. Google Wallet is officially supported on most NFC equipped mobile devices running Android 4.4 Kit Kat which introduced Host Card Emulation for NFC payments. BlackBerry devices have also supported NFC using BlackBerry Tag on a number of devices running BlackBerry OS 7.0 and greater. Mastercard has added further NFC support for PayPass for the Android and BlackBerry platforms, enabling PayPass users to make payments using their Android or BlackBerry smartphones in addition to a partnership between Samsung and Visa to include a 'paywave' application on the Galaxy S4 smartphone. Microsoft added native NFC functionality in their mobile OS with Windows Phone 8, as well as the Windows 8 operating system. Microsoft provides the "Wallet hub" in Windows Phone 8 for NFC payment, and can integrate multiple NFC payment services within a single application.
As of April 2011[update], several hundred NFC trials have been conducted. Some firms have moved to full-scale service deployments, spanning either a single country or multiple countries. Multi-country deployments include Orange's rollout of NFC technology to banks, retailers, transport, and service providers in multiple European countries, and Airtel Africa and Oberthur Technologies deploying to 15 countries throughout Africa.