Chapter 4

NFC Security and Privacy

Security is the degree of protection against an intentional or

accidental misuse or action. So far we have discussed the

working of NFC. This chapter gives analysis of security with

respect to NFC. It lists the threats, which are applicable to NFC,

and describes solutions to protect against these threats. All of

this is given in the context of currently available NFC hardware,

NFC applications and possible future developments of NFC

This chapter presents introductory knowledge on security;

vulnerability, threat, attack, and risk; cryptography; NFC

security issues and preventive mechanisms to handle the risks.

The content is provided for both those in higher, or managerial

and lower, or technical levels.

Potential readers are academicians, researchers, students,

consultants, practitioners, projectmanagers, software analysts,

system developers, and software developers.

Readers of this chapter will learn about the security and privacy

issues concerning NFC technology in detail. Hence they will be

able to design secure and interoperable

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1.6.1 Vulnerability, Threat, Attack, and RiskVulnerability is a weakness in a system which allows an attacker

to perform some actions that threatens its information

assurance.

A threat is a possible danger that may cause an unfair benefit

to the unauthorized user orcause harm by making use of

vulnerability

An intentional attempt by intruders to perform an

unauthorized access to information is called an attack

Attacks are classified as active or passive. If an attack does not

modify or delete a resource it is classified as passive, otherwise

it is classified as an active attack

The potential harm that may arise after the realization of some

threat is further defined as the risk

1.6.2 Security Tools and Mechanisms

Cryptography is also used for many purposes such as hiding the

content of the data froman unauthorized third party, or

preventing illegal modification of some transmitted data The

following are the basic services that are provided by

cryptography:

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_ the stored or exchanged information is not revealed to the

unauthorized parties.

_ the content of the stored or exchanged data cannot be

changed by unauthorized parties, or it will be noticed if it

occurs.

_ when the data are created or sent by some party, the party

cannot deny creating or sending them.

The idea of satisfying secrecy using cryptography is being able

to send the message in ascrambled form called a cipher text, so

that communication between the sender and the receiver

Is still possible, and can be performed using public channels

such as the Internet.

1.6.3 Security Issues on NFC Tag

Remember that the NFC tag is involved in reader/writer mode.

In this mode traditionally anNFC mobile interacts with an NFC

tag. In order to satisfy the overall security requirements,

The security of the data on the NFC tag as well as the security

of the communication between NFC devices must be secured

to handle the security ofthe same tag in NFC. Traditionally, the

following are the security issues related to the NFC tag:

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(i) Tag cloning

The attacker may try to clone, or create an exact copy of a valid tag. In orderto insert preventive mechanisms to the system, applications that require high Processing capability are required, increasing the cost of low-cost tags. ObviouslyThis is unfeasible and unacceptable, since the major point here is enabling low-cost NFC tags.

(ii) Tag content changes

The attacker may try to modify an NFC tag to change its content. In this way, several attacks become possible:

• Spoofing attacks

Spoofing attack is providing false information to the user which

seems valid, and hence possibly will be accepted by the user.

By spoofing attack, the user may insert a fake domain name,

telephone number or false information about the identification

of some person, item, or activity on to the tag.

• Manipulating tag data

The content of the tag might be changed by the attacker for

some malicious purpose.

• Denial of Service (DOS) attack.

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DoS attacks aim to damage the relationship between the

customer and the service provider. The primary way to do this

is by exhausting the system’s resources by forcing

It to perform some unnecessary and illegal action. This results

in decreasing and eventually exhausting the power source of

the server.

(iii) Tag replacement and tag hiding

The NFC tag may be replaced by a malicious tag, so that the

latter tag performs illegal actions as it is designed to do.

Sticking a malicious tag on top of the original tag or replacing

the original tag with a malicious tag is called tag hiding, and is

enough to let the system work as the attacker desires.

1.6.4 Security Issues on Communication

_ Eavesdropping: An unauthorized individual may use an

antenna in order to record communicationbetween NFC

devices.

_ DataCorruption: In addition to eavesdropping, an attacker

can try to modify the transmitted data.

_ DataModification: The attacker may try to modify or delete

valuable information by intercepting the communication.

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_ DataInsertion: Data may be inserted into the exchanged

messages between two NFC devices. The attacker must be fast

enough to send the data before the valid responder.

Theinsertion will be successful only if the inserted data can be

transmitted before the original device responds. If both data

streams overlap, the data will be corrupted.

_ Man-in-the-Middle Attack:These attacks are performed by

unknown parties in a communication, who relay information

back and forth by giving the simultaneous appearance of being

the other party.

_ Relay Attack: The attacker uses wireless communication to

borrow the data from the victim’s tag into another tag. This

means that the attacker inserts messages into the exchanged

data between two devices.

_ Replay Attack: A valid NFC signal is intercepted and its data is

recorded first; this is later transmitted to a reader so that it is

“played back”. Since the data appear valid, the reader accepts

them unless suitable prevention mechanisms are used.

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Figure 1-1. General Architecture of NFC enabled Mobile Phones

6.5 Secure Element

NFC enabled services must reassure users and service providers

that the transaction takes placein a protected environment.

This protection is achieved by using an SE which provides the

Security mechanisms required to support various business

models. The SE is a combination of hardware, software,

interfaces, and protocols embedded in a mobile handset that

enables secure storage.

An SE needs to have an operating system as usual. The

operating system (e.g., MULTOS, Java Card OS) supports the

secure execution of applications and the secure storage

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Of application data. The operating system may also support the

secure loading of applications.

If NFC enabled applications are saved and executed in the

memory of the NFC enabled mobile phone’s host controller,

these applications are not protected against unintentional

Deletion or intentional manipulation of the saved data in the

memory. They only transmit data between NFC enabled mobile

phones or collect information from smart posters. In

contactless ticketing, payment and other similar application

cases, security is an important issue. These applications use

valuable data, and the storage of valuable, private information

(e.g., creditcard information) in an unsecured memory is

unacceptable. The data could be transmitted via a GSM

interface to a third party who may misuse the information.

To solve this issue, relevant NFC applications need to be

executed and saved in the memory of an SE of the NFC enabled

mobile phone (see Figure 3.8). A variety of modules can serve

As SEs such as Universal Integrated Circuit Cards (UICCs) (i.e.,

SIMs), memory cards or embedded hardware. An SE is

necessary for various applications such as payment, ticketing,

Government and other applications where secure

authentication and a trusted environment are among the

prerequisites.

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_ Embedded hardware in a mobile device as an integral, non-

removable part of the device.

_ Secure Memory Card (SMC) as a secure storage area in a

removable smart card.

_ UICC as a physical smart card and maybe the most popular

one.

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Figure 2. Summary of SE Alternatives

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Embedded SE: Embedded SE is a smart card that is

integrated to the mobile phone, which cannot be

removed. According to the study the level of security

provided by this SE is as high as the one supported by a

smart card.

This chip is embedded into the mobile phone during

manufacturing process and must be personalized after

the device is delivered to the end user

Sticker: According to Moby Forum NFC sticker’s aim is to

allow Service providers a quick way to launch pilots and start

to deploy NFC Services such as payment, loyalty,

transportation, and so on. Two types ofStickers are available;

active and passive stickers. In theory, active stickersEnable

all NFC services and give NFC functionality to non-NFC

mobiles. Also life cycle management of active stickers is

possible because of theirConnection with the mobile

phones. They are mainly developed to give NFC

Functionality to mobile phones, however when NFC

mobile phones are spread all over the world, their

usage is decreased. There is not much practical

implementation of NFC services management with

stickers

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SMC: Secure memory card (SMC) provides same high-level

security as aSmart card provides, and it is compliant with

most of the main standards and interfaces of smart cards

with the removable property and a large capacity memory,

an SMC can host high number of applications in it. Currently,

most of the trials are performed on SMCs.

UICC: UICC is a generic multi-application platform for smart

card applications where SIM or USIM is implemented upon.

UICC provides an ideal environment for NFC applications

that are personal, secure, and portable and easily managed

remotely it can host no telecomApplications from various

service providers such as loyalty, ticketing,Healthcare, access

control, and ID applications Global Platform provides

The most promising standard for UICC life cycle

management (or namely cardContent management) with

three different business models; simple as MNO

Centric model, delegated model and full authorized as TSM

centric model However, there are still some unsolved issues

on UICC cardManagement in NFC based services. Hence

there is not any UICC smart card commercially available in

the NFC market

Flexible SE Solutions: In early years of NFC, because of lack

of NFCMobiles in the market, several alternative

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architectures have been proposed to enable NFC to the

mobiles without integrated NFC capability. Especially

SMC and SIM based SEs with built-in NFC antennas has acted

as anImportant NFC bridge devices (e.g., SMC hosting only

NFC antenna and SE,Or hosting NFC chip, antenna and SE

and so on) they shorten the time to-Market contactless

payment and similar applications. The study of proposes an

alternative that integrates NFC with SIM card; SIM

ApplicationToolkit

TMB: Trusted Mobile Base (TMB) is a promising upcoming

technology that isproposed by Moby Forum. It is hosted at

the root of the mobile phones andDefined as a secure

isolated section on the Core Processor Units (CPU) of

Mobile phones. Various secure NFC enabled applications can

beprovided flexibly via OTA technology. According to TMB

has the fullpotential of becoming a SE in the future.

6.6 Interfaces between SE and NFC Controller

There are various technical options for designing the interface

between the SE and the NFCcontroller. The most promising two

options are NFC-WI and SWP. The most important

Difference between them is that SWP uses one physical line

whereas NFC-WI uses two lines.It is worth mentioning that they

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are not alternatives to each other but options to be used in

certain places instead

(i) NFC-WI

NFC-WI (also called S2C) is a digital wire interface standardized

by ECMA 373, ISO/IEC 28361 as well as ETSI TS 102 541. The SE

is defined as a transceiver and the NFC controller is defined as

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front-end in this protocol. The SE is connected to the NFC

controller via two wires NFC-WI defines the Signal-In (SIGIN)

and the Signal-Out(SIGOUT) wires between the transceiver and

front-end as illustrated in Figure 3.12. Inthe standard [3], the

transceiver is the entity that drives the SIGIN wire and receives

on the SIGOUT wire. The front-end is the entity that drives the

SIGOUT wire and receives on the SIGIN wire. This digital wire

interface carries two binary signals which are defined as HIGH

and LOW. Both of them transmit modulation signals between

the NFC controller and the SE and are digitally received or sent

by the RF interface. The transceiver drives the SIGIN wire with a

binary signal of either HIGH or LOW. The front-end receives the

binary signal that is on the SIGIN wire. The front-end drives the

SIGOUT wire with a binary signal of either HIGH or LOW. The

transceiver receives the binary signal that is on the SIGOUT

wire.

Three transmission rates supported by NFC-WI are 106, 212

and 424 kbps. At 106 kbps (see Figure 3.13), the data stream

from the NFC controller to the transceiver (SIGIN) shall carry

the AND combination of the Modified Miller bit encoded data

with 13.56 MHz In the opposite direction (SIGIN) the data

stream is Manchester encoded and then inverted by a logical

OR operation with 848 kHz. At 212 and 424 kbps, the data

stream from theNFC controller for transceiver (SIGIN) is

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Manchester encoded and then inverted by a logical XOR

operation with 13.56 MHzThis corresponds to a PSK (Phase

Shift Keying)modulation of the clock signal. In the opposite

direction (SIGIN), the data stream is againManchester encoded.

NFC-WI is fully compliant and directly coupled with all modes,

types and data rates of ISO/IEC 18092 and ISO/IEC 14443, and

no additional adaptation and no protocol conversion is

required. It is a reliable concept which is feasible for immediate

implementation as well.

(ii) SWP

The next physical interface option is the SWP which defines a

single-wire connection between the SE and the NFC controller

in the mobile phone in contrast to the NFC-WI.