1.1.1. The era of mobiquity

In 2015, there were as many mobile phone subscriptions as individuals on the planet, with 7.3 billion connected mobile devices, around half of which are smartphones² (only half of this population has a bank account). Almost every individual on the planet has (or will have) a communication terminal, with very fast data processing, in his pocket. This means that around 3 billion people have a mobile phone, but no bank account. Half the planet owns a smartphone, among which 64% will be NFC enabled in 2018³, thus creating new opportunities of Internet services with added value: a banker, a guide, a tutor, a doctor, a counselor in our pocket. This prospect leads the way to unlimited creativity in terms of content, services and practices in the private, public and professional spheres the mobile phone crosses.

The era of the mobile Internet is only starting, the era of the Internet between objects and individuals, symbiont (J. de Rosnay), suppression of space-time (Michel Serres), creative destruction (Schumpeter), and mobiquity, which will be very productive in terms of innovations and research in all economic sectors: teaching, tourism, culture, mobile commerce, mobile payment (international fund transfer, virtual money, etc.).

The three key factors to the success of a new technological ecosystem are as follows:

• – usages;
• – usages;
• – usages.

A genuine engineering of mobiquitous services and applications was set up like illustrated by Apple’s AppStore concept or Google’s Market/Play Store (since 2013, more than 100 billion mobile applications are being downloaded in the world every year, according to Gartner Goup⁴).

Mobiquity is based on several technological concepts as follows:

• – Real world tags read by the end user’s mobile phone; these tags can be two-dimensional barcodes (such as the data matrix standard and its open source derivative, the QR code), radiofrequency tags (RFID; such as NFC tags), audio tags, even invisible tags with pattern recognition (such as Tokidev’s Snap’n See or Google’s Goggles). In 2020, one thousand billion tagged objects will exist, readable by our mobile phones, thus connected and alive from a biological understanding since life can be defined by the combination of information (here, the object’s unique identifier) and communication (via the mobile phone that has access to the tagged object’s history in a database).
• – Altered reality (augmented or diminished) with open source platforms such as Wikitude and Layar, allowing to enter database information (for example real estate information or tourist information) on the top of the real world viewed from the mobile phone, or, on the contrary, to remove/replace real-world elements (e.g. to imagine a new interior design, a new urban perspective, etc.).
• – Transmedia: A concept created by Martha Fisher in 1991 and followed up in Convergence Culture, a book from MIT Professor Henry Jenkins in 2003, with contents adapted to the five screens in our history (cinema, TV, computer, mobile phone and tablet); we must note that in this history of communication, the leading companies of contents and services for one screen were never the leaders for the next screen. The next screens will be on the walls (windows, mirrors, clothes, the skin, etc.).
• – Big data: According to IBM⁵, 2.5 trillion⁶ data bytes are generated every day, and 90% of the global data was created during the past 2 years. These data come from sensors, messages posted on social networks, pictures and videos published on the Internet, from geolocation (for example, GPS or NFC) from mobile devices (smartphones, tablets, smart watches), traceability logs for online payments (for example from e-payments or m-payments), keywords entered in search engines and, more generally, any digital information that can be used for interpretation (scientific data, fraud detection, medical, personal, behavioral data, etc.). Big data can be defined by “3V”: volume (“data tsunami”: 20 petabytes⁷ of data are processed every day by Google, and this has been the case since 2010, 1.8⁸ zettabytes were produced in 2011, meaning a 50% increase per year), variety (web data from social networks, linked data from semantic web, public data, open data and mobiquitous data coming from tagged objects and sensor networks, etc.) and velocity (data flow from sensors and social networks, real-time “on the fly”), to which we add a fourth “V”: variability (evolution), and a fifth “V”: valorization (improvement and enrichment).

1.1.2. Toward a world of contactless communicating objects

With NFC standards, any object can become “communicating” (and thus alive). Whether they are on the market, or developing, there is already a wide range of NFC-enabled devices and wearables: smart watches, bracelets, glasses, clothes or directly on our body. Smart devices increasingly become part of our daily life; parking meters, NFC mailboxes, fridges analyzing its users’ habits and forwarding the information to a smartphone (power consumption, temperature, door opening, etc.); connected oven able to pair with an NFC-enabled smartphone to suggest cooking recipes to the user and automatically set up a cooking function. NFC and its three operating modes (see section 1.3.2) in tag reader/writer, (smart) card emulation and peer-to-peer (P2P) represent a source of innovation for objects that have become “smart” because, specifically, of the smartphone’s connectivity.

NFC-enabled “objects” can be divided into two categories:

• – “Active” NFC-enabled objects (with a power supply) usually have an NFC reader: with or without graphic interface, they interact when brought into proximity with another peripheral device or an NFC tag. Most of the time, the “active” peripheral device hosts a “terminal” application, which means that its connectivity allows communication with a remote server paired up with a database in order to take information from the latter. In this way, the end user is able to trigger interactive and contextualized events whether they are processed locally or remotely for a result in the digital world (e.g. information display or secure payment) and/or in the real world (e.g. door opening).
• – “Passive” NFC objects are based on an NFC tag with no power supply; they activate when brought into close proximity with an “active” NFC-enabled object; they can then use the magnetic field power induced by the active device in “reader” mode, which then initiates the communication.

1.2.1. NFC tag

NFC tags can be of any kind and form: stickers, key rings, bracelets, etc. They offer the same functionalities as a QR code, but they do not require more than a simple “tap” with no user intervention, unlike QR codes that require the user to launch the right application to read it. NFC tags are the link between the real and the virtual world; they can also be used to activate or deactivate functions (alarms, devices, digital processing) and any other event triggered by a simple “tap” using a smartphone.

Figure 1.2 shows a (passive) NFC tag, here a transparent sticker, which belongs to the NTAG’s family produced by NXP.

Identification is a specificity inherent to NFC tags with an unmodifiable universal unique identifier (UID) attributed to them when manufactured. In this way, with no additional data needed, a connected object can simply be uniquely identified because of the UID of the NFC tag it is coupled to, whether the tag is stuck or embedded in this object. A “terminal” application connected to an NFC reader or executed in an NFC-enabled mobile device (in reader mode) can thus read the object’s UID depending on the use case of the application:

• – display information about the object (e.g. ID/electronic passports, touristic information, user guides);
• – execute a task (e.g. make a reservation);
• – start an event in the virtual world or even in the real world (door opening, alarm activation/deactivation, etc.);
• – save an event by adding available contextual data to it (e.g. the object’s UID, time and date stamp, geographical localization, user) for traceability or pointing purposes.

1.2.2. NFC smart card

The smart card is a more sophisticated type of tag with a sometimes hybrid communication interface (dual interface) providing both a traditional contact interface and an NFC interface enabling communication with services embedded in the smart card.

The contactless NFC smartcard is used as a payment card (in 2014, 600 million NFC payment cards were sold in the world⁹), as a transportation ticket as well as means of identification and authentication of the cardholder, for example for access control. The SIM card is the most widespread type (similar to a smart card, but smaller): there are as many active SIM cards as there are inhabitants in the world, and this is due to the fact that some users have more than one SIM card.

Embedded in an NFC-enabled mobile (smartphone, tablet), the smart card acts as a secure element (SE) in order to safely host services and confidential data. This configuration shows the advantage of extending services based on smart cards to smartphones’ advanced technologies (graphical user touch sensitive interface, audio, camera, embedded sensors, GPS, etc.) and, mostly, its web connectivity offers friendly user interfaces and improves services with new functionalities.

1.2.2.1. Smart cards and security

Enforced security is a broad field covering many aspects such as protection of privacy, access control, protection against viruses and hacking, integrity and data non-repudiation in the digital world.

Authentication is used to validate user identity. It can be attested through different, possibly combined factors (multi-factor authentication). For example, they can be based on:

• – the individual (biometric information);
• – a shared secret (password, PIN, encryption key);
• – an object (smart card, smartphone, etc.).

Permission/authorization consists of checking that the (authenticated) entity wishing to access a resource is permitted to do so. Permission management is done on an individual level or by a group of entities (permissions or restrictions can be defined according to roles).

Confidentiality is the guarantee that neither authentication data nor shared resources can be intercepted. Data encryption (cryptography) is the most widespread technique to preserve confidentiality.

Data integrity consists of making sure that resources do not experience any alteration, during data storage nor during the access to where they must be fully retrieved, with the same precision, but mostly by attesting their authenticity and their validity.

The public key infrastructure (PKI) standard is a method for cryptographic key management based on the principle of private key/public key:

• – a private key is generated in order to encrypt (or “encipher”) messages. Private keys remain secret and are never distributed;
• – one or several public keys are generated and distributed to encrypted message recipients and are used to decrypt the message (and encrypt replies).

In this way, a PKI-based system secures the provenance of the message (only encrypted messages with a private key can be decrypted with the public key) and confidentiality (only the owner of the public key can decrypt the encrypted message with the private key).

The main characteristics of PKI are based on software and hardware security:

• – the private key is stored in a secure electronic (SE) chip and never leaves it;
• – the public key is exported;
• – the encryption mechanism is hard coded in the chip;
• – the authentication mechanism is also embedded in the tamper-resistant technology of the smart card’s microcontroller.

In this way, smart cards are ideally suitable for identification and authentication purposes; among other things, they store an encrypted digital certificate in order to authenticate for a service. The most widely used cryptographic algorithms are triple Data Encryption Standard (3DES) with private and shared keys (in symmetrical reader mode) and the RSA standard¹⁰ with the distribution of a public key (in an asymmetrical mode). Keys can be loaded or generated on the smart card at the customization stage.

Europary MasterCard Visa (EMV) cards, chip-based debit–credit cards, as well as payment terminals and ATMs allowing the use of bank cards are widely deployed to attest the cardholder’s authentication. This is one of the reasons why smart cards are prime targets of security attacks. Smart card attacks go from physical intrusion of electronics (with a ionic probe, a microscope, a chemical attack or a laser, etc.), which lead to the destruction of the smart card, to semi-invasive attacks (with an oscilloscope) and non-invasive attacks (programmatically), which exploit weaknesses in the card’s hardware and software. Smart card manufacturers and security standards have developed simultaneously with attacks in order to incorporate countermeasures guaranteeing a maximum security and immunity during the card’s lifecycle; this is why it is important to only deploy recent smart card models whose technology incorporates full countermeasures to known attacks.

The most sophisticated smart cards are conceived with materials, which especially are dedicated to cryptography and encryption algorithm such as RSA and public key digital signature algorithms based on elliptic curve cryptography, used in asymmetrical operations for key exchanges on a non-secure channel or for asymmetrical encryption. The key pairs are generated inside the smart card in order to remove all risk of revelation of the private key, which is not distributed and thus remains unknown.

1.2.3. NFC smartphone

NFC smartphones answer five dimensions in a mobiquitous information system (the five “W”: who, where, when, whereabouts and what): holder’s identity (with his habits, his preferences), space and time (“here and now”, when he/she taps), goal to reach by tapping (information, transaction?) and result obtained (information, voucher, transaction, appointment, etc.).

The first NFC-enabled mobile phone was launched on the market in 2006 by Nokia: the Nokia 6131 NFC was delivered with an embedded SE (or eSE), for a default use of services (e.g. MasterCard, Visa©, SNCF) available on a service platform.

Today, all major smartphone manufacturers propose NFC-enabled mobile devices: Google first launched the first NFC smartphone in 2010 (Nexus S) with a primary strategy on mobile payment launched in May 2011 in New York. Since then, Samsung, Apple, then LG followed Google, offering their own contactless, mobile m-payment platforms, competing with the universal SIM card as an SE controlled by the MNO.

With or without SE, the NFC smartphone can act as an NFC tag (or a contactless smart card), but it can also act as NFC reader in order to read (or write) the content of tags, or even act as payment terminal, which might as well revolutionize secure transactions; so far, this field was for proprietary systems only, owned and controlled by professionals.

1.2.4. Reader/encoder: NFC transaction terminals

The NFC reader can read and write content on tags depending on formats determined by the NFC standard (see section 1.3). With or without a keypad and a screen, NFC readers are accessed by a program that allows reading/writing or communication with another NFC device (for example a tag or a smartphone) depending on the reader’s standards compliance.

1.2.5. “Smart cities” and sustainable development

Whether it be through infrared, Wi-Fi, Bluetooth® or NFC, we live in the times of “machine-to-machine” and connected objects: connected infrastructures equipped with sensors (pollution, humidity, light, temperature, motion, traffic jam, etc.), automated triggering (alarms, signals, urban lightening, public garden watering, etc.), electronic autodiagnostic, automatic detection of accidents and troubleshooting, etc.

NFC finds practical applications in eco-citizen life, for example in multimodality, which aims at offering all possible transportation solutions, possible connections from point A to point B: mobile applications allow us to locate, book and pay for ecological means of transportation (vélibs/blue bikes, electric vehicles, car share or public transportation), while calculating their availability and based on journey time, schedules, etc.

NFC is a universal connector with which any space can become a smart place: storing real-time medical data in a healthcare platform that would tell us when to go see a doctor, collecting statistics on power consumption directly on our mobile phone, benefiting from directions for use and being able to interact remotely, avoiding waste of time at a cash desk to pay for something.

All these concepts are in fashion, there are existing pilots and their emergence goes hand in hand with a mindset of sustainability. In this context, because of its low power consumption and its secure approach to communication, NFC will play a key role.

1.2.6. Cashless payment with NFC

E-commerce was born with the emergence of the Internet and online commerce; this new consumption pattern boomed with the appearance of smartphones and tablets, opening the way to m-commerce (whether it be geolocated or not), and m-payment has become a habit. Today, with technology we can select a product, wherever we are (at home, in the office or outside, alone or with others), whenever, whether it be day or night.

M-payment opened the way to dematerializing traditional means of payment (cash, cheque, bank cards): already globally tested out, the use of NFC standards seems to be the most appropriate technology to compete with bank cards (as a logical addition to blockchain transactions and cryptocurrencies).

The stakes are high since NFC could disrupt an established ecosystem and initiate a transition between banking monopoly toward new actors (MNOs, Google, Apple, Samsung) and the opening to private individuals with online banking management (money transfer from private bank accounts to third party accounts), then from our mobile phones (“bottom-up” approach in which the final user takes control vs. “top-down” approach where the bank service provider manages and controls everything).

The concept of virtual currency can also apply to unbanked populations: according to a 2012 World Bank study conducted on financial inclusion, 2.5 billion adults on the planet (almost half of the world population) have no bank account (among them, 70% have a mobile phone). This is a huge field for potential dynamization from which mobiquitous projects emerged on crowd funding or microfinance, whose exchange currency is not necessarily financial (for example livestock exchange and seed trade).

1.3.1. Analog signal and NFC digital transposition

Contactless communication consists of modulating and demodulating binary data (bits of value 0 or 1) in a signal (analog signal) by sending a wave (electromagnetic) called a “carrier wave”: through the creation of a variation in amplitude, phase and frequency, the signal is digitally transposed when received.

In its initial specification, the NFC standard gathers three types of codings:

• – NFC-A uses Miller (sender) and Manchester (receptor) codings with an amplitude modulation at 100% amplitude shift keying (ASK) (zero signal during breaks) at 106 kbps¹³;
• – NFC-B uses non-return-to-zero (NRZ) coding with an amplitude modulation at 10% ASK (still no signal during breaks) when sent and modulation through binary phase shift keying (BPSK) phase shift when received at 106 kbps;
• – NFC-F corresponds to FeliCa technology, which is commonly developed in Japan and uses Manchester encoding with an ASK amplitude modulation at 212 or 424 kbps.

NOTE.– The NFC forum is studying a new specification through which the standard (Tag Type 5) would be compliant with the vicinity cards signaling (standard ISO/IEC 15693) in the short range required by NFC.

1.3.1.1. ASK modulation

The transition (shift from 1 to 0 bit) occurs because of a shift in the amplitude of the signal: the amplitude is lowered or null.

1.3.1.2. BPSK modulation

With each transition, the signal’s amplitude is reversed, thus creating a phase jump.

1.3.1.3. Demodulation

Demodulation is a data extraction process that consists of converting an analog source into binary encoding.

1.3.2. The three standardized modes of NFC

NFC-enabled devices can support three operating modes, as illustrated in Figure 1.10:

• – reader/writer (i.e. tag reader/writer);
• – P2P;
• – card emulation (i.e. chip).

NOTE.– These three complementary operating modes of NFC standard are exclusive to one another.

NFC modes are based upon the ISO/IEC 18092 NFC IP-1, JIS X 6319-4 and ISO/IEC 14443 contactless smart card standards (referred to as NFC-A, NFC-B and NFC-F in NFC forum specifications).

1.3.2.1. NFC read/write mode

As illustrated in Figure 1.11, the read/write mode of NFC enables NFC devices to read and write information stored on passive NFC tags consisting of an antenna and an integrated circuitry. Power is supplied by inductive coupling from the NFC device initiator of the communication when it is brought into the proximity of the NFC passive tag.

Information stored on the NFC tag should comply with the record type definition (RTD) standard specified by NFC forum or be a proprietary format (see section 1.3.3.3.2).

Different types of NFC tags are described by the standard (see section 1.3.3.3.1): in the NFC tag, data are stored in NFC data exchange format (NDEF) messages (see section 1.3.3.2) that include type, type format, ID and byte array. For example it is possible to write download links/URLs into the NFC tag, which can store several records. A mere reference can also enable the device to recollect linked data from a remote server, for example using dedicated web service.

The NFC-enabled device can, with prior end user acceptance or automatically, launch the appropriate application to access the linked content (for example text, media picture/audio/video, web page) or trigger an electrical action (for example switch-on the light), a mechanical or olfactory action.

1.3.2.2. NFC card emulation mode with SE

NFC card emulation mode enables NFC devices to act like smart cards, allowing users to perform transactions such as mobile payment, ticketing and transit access control with just a tap. In this mode, the contactless layer and RF fields act as a transport for smart card standard (ISO/IEC 7816), as illustrated in Figure 1.12.

In card emulation mode, NFC devices communicate with an external contactless reader: the NFC card emulation mode allows the handling of already existing protocols on top of NFC stacks with no change in infrastructure (see Figure 1.12). For NFC payment applications, this NFC card emulation mode is based upon the EMV standard and PIN card specifications.

NFC card emulation mode involves a tamper-resistant hardware component called “secure element”. The SE is a multiservice chip with its own microprocessor (CPU) and a crypto-processor, its own operating system (JavaCard™) as well as volatile and non-volatile, including Erasable Programmable Read Only Memory (EPROM) with a storage capacity up to 6 Gb, input/output interface to receive messages and send responses and one or several (for example contact/RFID hybrid card) power supply interfaces. It can either be a standalone (contact or contactless) smart card or a component of a host device (e.g. a smartphone or a tablet) with, in that case, three possible SE configurations, as illustrated in Figure 1.13:

• – in the SIM card or the universal integrated circuit card, handled by an MNO;
• – embedded in the device (eSE) and handled by the device manufacturer (for example Apple, Samsung, LG);
• – external/removable secure memory cards such as the micro Secure Digital (microSD).

The SE could be accessed remotely in the Cloud, and/or emulated by a background service that behaves like a (hardware) SE. This mode, which is not hardware based, is called the host-based card emulation (HCE) mode.

The SE is mainly intended to securely store confidential data (e.g. account data, identification, user credential, encryption/decryption keys). Processes running into the SE (outside the main OS of the host device) are commonly called Applets (inheritance from JavaCard™), Cardlet or Servlet; the application that allows the user to manage a set of virtual cards and services digitalized into the SE is called a Wallet.

SE-related standards are centralized by GlobalPlatform (www.globalplatform.org), the international cross-industry standardization organization adopted as global reference by MNOs with the GSM Alliance (GSMA) and European Telecommunications Standards Institute, as well as banking institutions (e.g. EMV) and other standardization bodies, including the NFC forum.

1.3.3. NFC forum standards

The NFC Forum was founded in 2004 by Philips Semiconductors (then NXP) and Nokia, the inventors of NFC, and then joined by Sony. It is a non-profit industry association whose objective is to develop and promote NFC technology. NFC forum specifications are based upon the ISO/IEC 14443 standard, which slightly differs from ISO/IEC 18092 standard in terms of RF layers and NFC P2P mode which was addressed by the NFC forum in 2011 (see Figure 1.14).

NOTE.– The use of “N-mark” (see Figure 1.15.) shows compliance with NFC forum specifications. Signing the license agreement for brand use is required in order to acquire N-mark.

NFC forum application documents provide guidance on how to take advantage of contactless NFC technology in specific targeted scenarios. For example, in the application documents (i.e. for NFC) provided by the NFC forum, we can find guidance on how to use NFC for secure Bluetooth® pairing: this application document describes the interactions between Bluetooth® and NFC technologies. It provides examples of both protocol implementation and data transfer for the most appropriate use cases of these two technologies. Developers will find useful guides for their own work. The document was expanded (in June 2014) to the Bluetooth low energy technology, a version of Bluetooth technology that offers reduced power consumption (NFC forum, “Bluetooth Secure Simple Pairing Using NFC Application Document”, 2011).

In this way, when used with NFC forum specifications, these tools can help achieve full interoperability across technologies: technical documentation and tools suggested by the NFC forum offer guidance on best practices and NFC implementation solutions (free of charge for NFC forum members, charged for non-members), as listed below:

1. 1) NFCIP-1 (ISO/CEI 18092) communication interface protocol standardized by the ISO/IEC 18092 and ECMA-340 standard (suitable for devices pairing in P2P mode). The protocol stack in NFCIP-1 is placed on top of the NFC-A protocol layer (see section 1.3.1.) defined in ISO/IEC 14443 and type 3 tags of NFC forum (see section 1.3.3.3.1). NFCIP-1 includes both passive and active communication modes, which allow an NFC device to communicate with other NFC devices in a P2P manner:
   • – active communication mode means both the initiator and the target are using their own self-generated and self-modulated RF field to transmit data;
   • – passive communication mode means that the NFC target device responds to an initiator command in a load modulation scheme (using the energy induced by the RF field generated by the initiator).

   NOTE.– NFCIP-2 (ISO/IEC 21484) is the specification for the selection mechanism between different contactless technologies that operates on the same frequency at 13.56 MHz. It supports communication according to ISO/IEC 18092, ISO/IEC 14443. This specification is also compatible with other contactless technologies like Vicinity cards (ISO/IEC 15693) that is also known as NFC-V, currently reviewed by NFC forum (i.e. in order to offer a specification including vicinity compliance with NFC standard).

2. 2) ISO/IEC 14443 standard describes contactless integrated circuits communication interface protocols divided into four parts:
   • – 14443-1: physical characteristics;
   • – 14443-2: RF power supply and signal interface;
   • – 14443-3: initialization and anticollision mechanisms;
   • – 14443-4: transmission protocol.
3. 3) NDEF logical format of data exchange (see section 1.3.3.2).

1.3.3.1. NFC forum protocols specifications

A standard specification document explicitly describes a set of requirements of technical criteria, methods and processes. In systems and software engineering, it is intended to establish a guidance for the development and the implementation of the system (software or hardware) describing for example what must/may/shall or not be done and how. Each provider can develop their own specification implementation.

NOTE.– The NFC forum proposes a certification program for the providers who want to have their products certified and ensure they are compliant with NFC forum specifications. NFC forum specifications are related to communication protocols and application (messaging) layers of the OSI model including the tag types.

NFC LLCP protocol based on Open Systems Interconnection (OSI) message authentication code layer-2 of IEEE 802.2 standard (see Figure 1.17), ISO/IEC 18092 and ISO/IEC 14443 supporting P2P between two NFC-enabled devices for bidirectional communication. It is used on the top of NFCIP-1.

LLCP protocol specification describes the format of protocol data unit (PDU) exchange structures made up of header and payload (see Figure 1.18):

• – LLCP PDU format is as follows:
  • - destination service access point (DSAP);
  • - payload type (PTYPE);
  • - source service access point (SSAP);
  • - PDU sequence;
  • - Payload.
• – NFC digital protocol on the top of ISO/IEC 18092 and ISO/IEC 14443 and JIS X6319-4 standards gathers common features and digital interface and the half-duplex transmission protocol of the NFC-enabled device in its four roles as initiator, target, reader/writer and card emulator.
• – NFC activity provides communication setup between NFC devices: Profiles specific configuration parameters, polling for an NFC tag or NFC device in combination, NDEF data, etc.
• – NFC simple NDEF exchange protocol for NFC-enabled devices messaging over LLCP.
• – NFC analog: RF interface (signal form, time/frequency/modulation characteristics) and power requirements of the NFC-enabled device in its four roles (P2P mode initiator, P2P mode target, reader/writer mode and card emulation mode) for all three technologies: NFC-A, NFC-B and NFC-C (depending on signal modulation/demodulation methods) and for all the different bit rates (106, 212 and 424 kbps).
• – NFC controller interface between NFC controller and the device’s main application processor.

1.3.3.2. NDEF data exchange format

NDEF defines the data format structure of an NFC message to be read or encoded in a tag. NDEF messages have a header and one or several NDEF records with a header for each of them.

As illustrated in Figure 1.20, the first bytes are used by the header:

• – MB: message begin on 1-bit taking a value of 1 if the message starts, otherwise 0.
• – ME: message end on 1-bit taking a value of 1 if the message ends, otherwise 0.
• – CF: bit indicates a chunked payload.
• – SR: bit indicates a short record on 7 bytes instead of 10.
• – IL: bit indicates if ID length bytes and ID must be read.
• – TNF: type name format on 3 bits.
• – 0x00: empty record.
• – 0x01: well-known type defined by NFC forum (see Table 1.2).
• – 0x02: MIME type (text, media, picture, etc.).
• – 0x03: URI.
• – 0x04: external.
• – 0x05: unknown type.
• – 0x06: unchanged (for chunk records).
• – 0x07: reserved for future use.
• – Type length: length of the PTYPE field on 8 bytes.
• – ID length: size of the payload ID field on 8 bytes.
• – Payload length: specifies the length of the payload field whose size is determined by the SR field.
• – Type: record type (see Table 1.2) in hexadecimal (e.g. “U” for URI, value 0x55).
• – ID: type ID or hexadecimal prefix (e.g., 0x01 is “http://www”).
• – Prefix: according to TNF, for example for URI type:
  • - 0x00: no prefix;
  • - 0x01: http://www;
  • - 0x02: https://www.
  • - 0x03: http://
  • - 0x04: https://
  • - 0x05: tel:
  • - 0x06: mailto:
  • - 0x1D: file://
  • - 0x24…0xFF: reserved for future use.
• – Payload: content the size of which is determined by payload length field.

1.3.3.3. NFC forum tag types

NFC tags’ content and capacity differ according to their characteristics, from tags locking and unlocking write capabilities, storing one or several messages linked to Internet content, to more complex tags like smart cards capable of embedding data as well as applications.

1.3.3.3.1. NFC tag types

Four NFC tag types (see Table 1.3) are defined according to compliance with various standards and protocols.

In Table 1.4, a level of protocol in the activation phase of communication and data exchange differentiates the tag types.

Type 1–4 tags are all based on existing contactless products:

• – NFC forum type 1 tag based on the ISO/IEC 14443 standard is rewritten capable over 96 bytes (expandable to 2 kb). The Innovision Topaz Tag (from Broadcom) is the most commonly used Type 1 tag.
• – NFC forum type 2 tag based on the ISO/IEC 14443A standard is rewritten capable over 48 bytes (expandable to 2 kb). Mifare Ultralight and NTAG tags (NXP) are the most commonly used type 2 tags.
• – NFC forum type 3 tag is preconfigured at manufacturing to be both read and rewritable, or read-only, theoretical memory limit is 1 MB per service. Type 3 tags are based on Japanese Industrial Standard (JIS X 6319-4); Felica tags (Sony) are the most commonly used.
• – NFC forum type 4 tag (defined in November 2010) is fully compatible with the ISO/IEC 14443 standard series. Tags are preconfigured at manufacturing to be either read and rewritable, or read-only, memory variable up to 32 kb per service; the communication interface is either Type A or Type B compliant. These tag types can be interfaced on the application level according to ISO/IEC 7816-4 Application Protocol Data Unit (APDU). These type 4 tags are usually used for contactless transaction payments and ticketing, such as Mifare DESfire (NXP).

1.3.3.3.2. Record type definition

Record types used by NFC forum application and third parties are based on the NDEF data format described in section 1.3.3.2. Five specific RTDs are defined (see Table 1.2): Text, URI, Smart Poster, Generic Control and Signature.

1.3.3.3.3. Reference applications

NFC forum connection handover was determined in 2010 to enable a static and dynamic one-touch setup of NFC with high-speed communication technologies, such as Wi-Fi setup or Bluetooth® pairing.

NFC forum also has a standard for communication with peripheral devices dedicated to healthcare technologies (NFC Forum Personal Health Device Communication) and based on ISO/IEC/IEEE 11073-20601 standard (Health informatics).

1.3.4. GlobalPlatform (GP)

Based on “Visa© OpenPlatform” standards in the hands of the OpenPlatform consortium, become GlobalPlatform (GP) in 1999, GP was created to meet the interoperability needs emerging from the globalization of payment transactions via smart cards; its main objectives were to promote the security, development platforms and management of the deployment of smart cards and SEs standardization.

GP acts upon interoperability for actors of the NFC ecosystem in card emulation mode, and especially upon SE management. It issues specifications and instructions on the ecosystem, especially security rules, protocols, architectures and card interfaces (card specifications²⁰), devices (device specifications²¹) and systems (systems specifications²²); GP defines use case scenarios, design patterns, frameworks and APIs in order to ease SE services implementation (some resources have limited access: free for members and charged for non-members).

1.3.4.1. GP cards specifications

Specifications of this section address architecture, interactions, interfaces and smart card security, regardless of the underlying technologies (i.e. regardless of the manufacturer or the card OS). Resources in the card section more specifically address smart cards issuers (aiming at hosting third party applications).

Figure 1.21 shows hosted services in a dedicated secure execution environment, security domain (SD) including GP standard-compliant API layer for key management, encryption/decryption, signature and access control, support of application portability between GP-compliant cards. We can note the SD intended for the card provider, just like another one dedicated to controlling authority (for keys and certificates management). “OPEN” API provides standardized functions for the interfacing and the lifecycle management of GP-compliant services, including a framework for secure interapplications communication.

OPEN supports the following management functions:

• – commands execution;
• – application or SD selection;
• – logical channel management (i.e. disregarding physical channels);
• – command sending;
• – card content management;
• – content control;
• – content setup;
• – content removal;
• – access control rules for content management;
• – security management;
• – blocking/unblocking;
• – card terminal;
• – privileges management;
• – traceability and event log.

Specifications thoroughly describe state transitions of the lifecycle, APDU instructions for the management of card content and recommendations for secure communication channel setup (PKI, authentication modes, encryption and decryption, session setup, etc.).

1.3.4.2. GP device specifications

The device resources section is dedicated to original equipment manufacturers and more specifically for mobile environments. Specifications are also for developers who interface with peripherals mentioned in this section.

This section addresses two environments:

• – SE with its own OS;
• – trusted execution environment (TEE) running in the host device memory.

TEE includes secure storage in which functions are executed in an isolated area of the memory space from the OS (separated by firewalls); communication with devices (for example screen, SIM card or SE) uses secure channels, thus securing coding instructions privacy and so-called “trusted” application data.

Applications and tools recommended by GP are related to the architecture, access control and communication interfaces of local (i.e. from the host device) or remote (i.e. from an external server) client applications. For example, Figure 1.22 shows how an administration session request is triggered on the remote admin server demand toward an Admin Agent application in the mobile device; then, the mobile sets up a secure HTTPS connection (requiring authentication) with the server to collect APDU instructions to be transmitted to the SE.

1.3.4.3. GP systems specifications

This section is devoted for every stakeholder who designs and implements administration systems as well as management systems for smart cards and their content: these specifications define the role and responsibilities of each actors of the ecosystem in a secure infrastructure of multiple application cards’ environment and describe message exchange format, protocols and interfaces.

Specifications include a mediator platform called trusted service manager (TSM). The TSM provides a standardized API that allows providers of NFC services hosted in an SE to interface with the management systems of the SE issuers (SEIs) or the MNOs that are handling end-user’s subscriptions. GP describes the SOAP secure web services into XML files (WSDL and XSD) intended for the lifecycle management (and audit) of remote applications like (among others):

• – service deployment;
• – suspension/lock/unlock;
• – update;
• – service removal.

Figure 1.23 illustrates the SE content management triggered by an “Actor B” (for example on behalf of the service provider, i.e. TSM) authorized by an “Actor A” controlling the SE (the SEI or the MNO) according to three delegation modes:

• – in simple mode, only the SEI is authorized to perform card content management. TSM can verify loading with data authentication pattern (signature);
• – in delegated mode, the TSM is authorized to perform card content management by acquiring a prior authorization from the SEI with token management;
• – in authorized (dual) mode, the TSM has full access to a dedicated SD by acquiring a prior authorization from the SEI.

The GP messaging (GPM) system is the standard interface for the remote management of the service lifecycle by the TSM as shown in Figure 1.24. The figure illustrates an example of deployment notification (and function calls) triggered by the TSM to the SE provider as well as to the MNO; then, each can update the service state and proceed appropriate actions. For each actor of this ecosystem, GPM thoroughly describes the end-to-end use cases in the three modes of the SE service management, for each step and events of the lifecycle.

1.3.5. SIMAlliance and open mobile API

SIMAlliance is a non-profit organization involved in mobile device technologies and especially in SIM cards. SIMAlliance aims at easing secure mobile services development and management and simplifying hardware-based device security. Members of the organization are actors of digital security, smart card and mobile services such as Gemalto, Oberthus, Giesecke & Devrient (G&D), Incard and Morpho (Safran).

SIMAlliance gives specifications of its Open Mobile API (OMAPI)²⁷ standard for mobile applications: OMAPI defines a reader-like interfacing (i.e. smart card reader) with the SE regardless of the configuration (i.e. SIM-SE, eSE or MicroSD); OMAPI was adopted as a standard by GP and the API was adapted in order to be compliant with ETSI and GSMA specifications. EMVco also commissioned SIMAlliance to adapt API to contactless transaction payment (NFC Tagify, February 2016²⁸).