Li S.Z., Jain A.K. (eds.) Encyclopedia of Biometrics

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typically a greyscale image in which ﬁnger vein pat-

terns are imaged as dark area.

▶ Finger Vein Biometric Algorithm

Read Noise

For image sensors, each time when a pixel is read out,

there is noise associated with the act of reading the

pixel. This noise is, to ﬁrst order, independent of the

value of the pixel.

▶ Biometric Sensor and Device, Overview

▶ Iris Device

Real-Time 3D Surface Digitization

Many 3D biometrics applications rely on laser scanners

for surface digitization. Although these devices pro-

duce very accurate 3D coordinates, they have two main

limitations. They are expensive thus prohibiting their

use in a wide scale, and they require the user to stay still

during the acquisition. The latter is because during

acquisition, a laser beam sweeps the object surface,

and thus movement may results to artifacts. 3D acqui-

sition based on the stereoscopic principle is an alterna-

tive without the above limitations, since two plain

cameras are used. However the accuracy of such

devices is usually limited. A solution that is a compro-

mise between the above is using sensors that are based

on the structured light approach. The surface of the

object is illuminated by a l ight pattern (e.g. by means

of a slide or video projector) and the resulting image is

captured by a common camera. By analyzing the de-

formation of this pattern on the surface 3D coordi-

nates may be computed by means of triangulation. The

accuracy of this approach has been shown to be ade-

quate for biometric applications.

▶ Finger Geometry, 3D

Recognition at a Distance

Recognition at a distance is the process of establishing

the identity of humans in a non-intrusive way from a

distance, often without their knowledge. Typically, face

and gait biometrics are used to perform recognition

from small to mid range distance.

▶ Face Recognition, Video-based

Rectilinear

Moving in, consisting of, boun ded by, or characterized

by a straight line or lines. Rectilinear images are those

in which intensity values are recorded as a matrix, w ith

each element in the matrix corresponding to the inten-

sity measured by a single picture element (pixel) in the

image sensor.

▶ Iris Image Data Interchange Formats, Standardization

▶ Iris Standards Progression

Reference Set

Reference set is a set of biometric samples or extracted

features from a biometric trait of a user, which are

stored to perform matching. Stored samples are also

known as templates. Generally, each input biometric

sample will be compared to all the templates in the

reference set in the matching phase. Reference-based

systems are opposed to model-based systems, where

instead of storing genuine samples, a classiﬁer is

trained (or a statistical model is estimated) from the

training set.

▶ Performance Evaluation, Overview

▶ Signature Matching

1110

Read Noise

Reflection

When light impinges on a object, part of the light is

reﬂected, it bounces off the object; part of the light

is transmitted, it passes through the object; and part of

the light is absorbed, it is converted from light into

some other form of energy in the object.

The reﬂected light can be divided into two compo-

nents, specular and diffus e. A specular reﬂection is

what you see in a mirror; a single ray of light is

reﬂected back as a single ray of light in a new direction

determined by the rule that the ang le of reﬂection with

respect to a normal to the surface equals the angle of

incidence with respect to the same normal. Diffuse

reﬂection is what you see from a matte surface; a single

ray of light is reﬂected back over a broad range of

angles. Most materials have specular and diffuse com-

ponents to their reﬂectivity.

▶ Iris Device

Reflection-Based Touchless Finger

Imaging (RTFI)

RTFI refers to touchless ﬁngerprint sensor.

▶ Fingerprint, Palmprint, Handprint and Soleprint

Sensor

Region-of-Interest (ROI) Encoding

It is often desirable to allocate a coding budget non-

uniformly to an image, especially when compression is

required. This may take the form of space-variant

resolution, so that only some favored region receives

maximal resolution while other areas are encoded

with coarser resolution; or it may take the form of

completely masking out the irrelevant areas. The

capability to specify a Region-of-Interest (ROI) is

built into advanced coding protocols for image com-

pression, especially the JPEG2000 protocol (ISO Stan-

dard 15444) which allows binary masking as well as

code-block selection so that different resolution levels

and different coefﬁcient scaling can be applied to dif-

ferent tiles. The older JPEG protocol (ISO Standard

10918), in its Part 3 extension, also supports variable

quantization for explicitly specifying different quality

levels for different image regions.

In JPEG2000, the MAXSHIF T tool allows speciﬁ-

cation of an ROI of arbitr ary sha pe. ROI methods

have been developed for compact encoding of iris

images so that nearly all of the available coding bud-

get is allocated to the iris itself, and not was ted on

costly irrelevant structures such as eyelashes. In these

methods, the non-iris regions of an image (eyelids,

eyebrows, eyelashes, skin and sclera) are all automati-

cally d etecte d and painted out wi th uniform gray

values before JPEG or JPEG2000 compression, result-

inginalmostnocodingcoefﬁcientsbeingwastedon

them and allowing image ﬁle size to be reduced

to 2,000 bytes.

▶ Iris Recognition Performance Under Extreme Image

Compression

Registered Traveler

CATHERINE J. T ILTON

Daon, Reston, VA, USA

Synonyms

Known traveler; Trusted traveler

Definition

Registered Traveler (RT) programs are designed to

expedite legitimate travelers through a border control

or security screening process by conducting a

▶ secu-

rity threat assessment to determine risk levels prior to

acceptance into the program and passage through a

designated travel lane. These programs are generally

Registered Traveler

1111

voluntary and involve the collection of biographic and

biometric data used in background checks. Often, they

involve the issuance of a secure biometric credential

that can be used as part of an identity veriﬁcation

process.

Registered Traveler or Trusted Traveler programs

are airline passenger security assessment systems

deployed in the USA and controlled by the transporta-

tion security a dministration (TSA) as public/private

partnerships. Their purpose is to expedite the security

screening procedures for departing air passengers who

have been previously vetted by TSA and deemed, on

the basis of background checks, to be minimal security

risks. To use the expedited fast lanes at airports, trave-

lers must prove their identity and qualiﬁcation under

the scheme by either ﬁngerprint or iris recognition,

matching their own biometric record that is securely

encrypted on a smartcard issued by TSA and interop-

erable across dozens of US airports.

The larges t such programme is call ed CLEAR oper-

ated by Veriﬁed ID, which has enrolled more than

175,000 fee-paying members.

Introduction

Today’s traveling public wants it all – hassle-free, se-

cure, and safe travel. However, security usually means

additional inconvenience. As a result, user-friendliness

is sometimes seen as a trade-off for enhanced security.

In the wake of the events of 9/11, national security and

transportation ofﬁcials worldwide were faced with this

challenge: How to heighten the security of transporta-

tion, travel, and border systems while minimizing

delays, aggravations, and privacy intrusions?

One idea that has gained some momentum is reg-

istering travelers in advance such that those travelers

can be expedited through one or more of the travel

processes – usually security screening and/or border

control points. The idea is that by prescreening trave-

lers, along with a strong identity authentication

method, they can be segregated into risk categories,

allowing security ofﬁcials to allocate greater attention

and resources to ‘‘unknown’’ or high-risk travelers [1].

Goals of RT programs generally include the

following [2]:



Enhance security



Facilitate legitimate travel and trade



Protect personal privacy

Participation in registered traveler programs

involves a registration process in which the applicant

provides biographic informati on and enrolls his/her

biometrics. This information is used to conduct risk

assessments (or security threat assessments) that may

include criminal background and watchlist checks. The

cognizant agency then makes an adjudication decision

as to w hether the individual is eligible for the program.

Beneﬁts of participation from a traveler’s perspec-

tive include shorter lines, faster processing, and con-

sistency of experience. So me programs also offer other

commercial beneﬁts (e.g., preferred parking, con-

cession discounts). When used to expedite security

screening, one of the main beneﬁts expressed by parti-

cipants is predictability of wait times, allowing them to

better judge time allowances and thus to spend more

time at home or work prior to travel. This appeals

mostly to frequent business travelers who are willing to

pay for such an advantage. ‘‘The Privium (See ‘‘Example

Systems’’) experience suggests that travelers are a great

deal more willing to submit to ﬁngerprint and iris scans

if they think it will save them time and effort [3].’’

RT programs exist in the US, Europe, and other

locations and are emerging elsewhere. The US program

centers on the security screening function, whereas

many other programs focus on the border control

area (i.e., immigration stations at ports of entry).

Nearly all such programs are implemented at airports;

however, this is not universally true. It is seen by many

as a method for ‘‘simplifying passenger travel’’. A few

such programs are highlighted in the examples section.

The RT Process

The processes used within a registered traveler pro-

gram are similar to those used in typical biometric-

based

▶ credentialing systems. (An example of a

credentialing system is the personal identity veriﬁca-

tion program in the US.) [4] At a high level, the process

comprises three elements: (1) Registration, (2) Authen-

tication (Use), and (3) Administration. Depending on

system architecture (see next section), these can be

further broken down into component operations.

Registration is the process of enrolling and vetting

an applicant to determine and instantiate eligibility.

This generally involves the following steps:



Preenrollment (optional). This step involves the

applicant providing biographical information

(usually via some remote means, such as the

1112

Registered Traveler

internet) in advance of in-person, full enrollment.

This may also include the scheduling of the enroll-

ment appointment, receiving instructions, and

payment of any associated fees.



Biographic enrollment. The applicant either pro-

vides the requested biographic data or veriﬁes/

corrects those supplied during preenrollment.

Biographic information would normally include

name, date/place of birth, address, employment,

and relevant identiﬁcation numbers.



Identity prooﬁng. This entails the applicant providing

one or more identity documents (e.g., birth certiﬁ-

cate, drivers license, passport, or government issued

ID),whicharethenscannedandvalidated.



Biometric enrollment. Usually ten ﬁngerprints as

well as a facial photograph are captured, as these

are the norm for criminal background checking.

Some programs capture additional or alternative

biometrics such as iris images.



Identity investigation . Using the information

provided by the applicant, one or more of the

following checks may be performed as part of

the security threat assessment (STA):



Name-based background checks, which may

include veriﬁcation of the existence of the

claimed identity



Biometric duplicate checks, to ensure that an

individual is not enrolled into the system under

more than one claimed identity



Criminal history checks



Watchlist checks, including but not limited to

known or suspected terrorists



Adjudication. Based on the results of the STA, the

cognizant authority makes a decision as to appli-

cant eligibility.



Credential issuance (optional) and notiﬁcation.

Most RT programs issue to approved participants

a physical credential, such as a smartcard (or

e-Passport) that is used in subsequent processes;

however, this is not strictly required as a central

server-based architecture is also possible. When

used, these credentials serve as the claim of identity

when presented, but also may contain biometrics

that can be used to verify that claim during an

authentication operation (this is discussed further

in the following section).

Authentication is the process of verifying identity

and program participation at the designated point

in the travel process. This usually involves a claim

of identity (either explicit or implicit), biometrically

verifying that id entity against the enrollment and

validating the privilege of the participant. The last

step may include:



Checking the validity of the credential including

expiration, revocation, integrity, and security

features



Checking that the participant’s priv ileges have not

been revoked or other wise invalidated.

Authentication is frequently performed at

(attended) veriﬁcation kiosks located at RT privilege

lines. The outbound users may need to ﬁrst show a

boarding pass and an ID (an RT card or a government-

issued ID) before approaching the kiosk. He or she

would then present his or her RT card e-Passport to the

kiosk (in a credential based system), present his or her

biometrics to the sensor when challenged, and be veriﬁed

to pass through if his or her biometrics match. In most

schemes, if biometric veriﬁcation fails, the participant is

moved the head of the regular queue. Some multibio-

metric RT systems allow the trav eler to select their pre-

ferred veriﬁcation biometric (e.g., ﬁngerprint or iris).

Administration includes both normal system oper-

ation and maintenance functions as well as ongoing

privilege managem ent such as suspension or revoca-

tion of privileges, renewal and re-issuance, and some-

times periodic refresh of eligibility checks (i.e., running

a participant back against the current watchlist).

Architecture

As you might exp ect, several architectural alternatives

exist for RT schemes. Major architectural decisions

include whether a centralized or distributed model

will be used (this primarily relates to where the bio-

metric matching operations are performed) and

whether or not it will be federated (i.e., the degree of

autonomy and commonality of design among service

locations). Other decisions involve whether or not it

will be credential based, single or multimodal, and

whether a one-to-one (1:1) or one-to-many (1:N)

technolog y will be employed.

In a centralized model, most majo r operations are

performed at a central server. Participant facing opera-

tions are still performed locally (for example, informa-

tion collection and biometric captures). However, all

data storage/management and biometric matchin g are

Registered Traveler

1113

performed at the server. In a distributed model, data

may be stored at the operational site(s) or on a creden-

tial and matching may be performed locally as well.

In a federated system, the architectural model is set

and interfaces between major components are deﬁned,

but the local systems may be deﬁned and controlled by

multiple different entities, although some common

requirements will apply (e.g., security). For example,

in the US Registered Traveler system (see System

Examples, below), which is setup as a public/private

partnership, each enrollment and veriﬁcation site is

owned and operated by a given

▶ service provider

(SP), which is contracted by a location sponsor (e.g.,

an airport). Design of the speciﬁcs of the enrollment

station and veriﬁcation kiosk, including capture equip-

ment, process ﬂow, and internal databases, is SP-

speciﬁc, although elements that affect interoperability

across the system are controlled by a system interoper-

ability speciﬁcation and conformance testing to that

speciﬁcation is performed. A central element still

exists, of course, to perform those functions that re-

quire it (e.g., duplicate checking, STA gateway, payload

generation/signin g, etc.)

If a credential-based system is used, then there are a

number of design elements involved including the

card-operating system, data model, and card edge

speciﬁcation as well as whether the card personaliza-

tion and issuance will be performed centrally, by an SP,

or locally. Depending on the degree of federation, ele-

ments of the card topology (what it looks like on the

outside) may also be strictly speciﬁed (e.g., whether/

where a name and facial photo will be printed

on the card). A very basic and important decision is

whether a contact, contactless, or dual-interface card

will be used. Security and privacy models must also

be determined including how the personal information

(including biometric data) will be protected, security

features (topographical and digital), and tamper resis-

tance. For contactless cards, this includes the prevention

of covert reads and snifﬁng of RF communications

during use. Figure 1 depicts a high level architecture

and process ﬂow for a federated, credential-based RT

system.

In selecting the biometrics to be enrolled, stored,

and veriﬁed, needs for background checking and oper-

ational use must be considered. Generally, background

checking requires the collection of ten ﬁngerprints

(tenprints) as this is the standard for such systems;

however, this may or may not be the biometric of

choice for operational use. Considerations such as

social acceptability, accuracy, and ease of use will

drive this decision. To broaden the user population

and reduce false rejections, a multimodal system may

be employed. In this case, multiple biometrics are

captured during enrollment and the participant may

choose a preference at the time of enrollment or at

veriﬁcation. The need to be able to verify any of the set

of supported modalities will, however, drive up the

cost of the enrollment and veriﬁcation stations as mul-

tiple capture devices will be required.

It is important to note that in order to perform

duplicate (uniqueness) checking, the biometric collected

Registered Traveler. Figure 1 Federated RT Model.

1114

Registered Traveler

for this purpose must be captured (or attempted to be

captured) from all participants – otherwise, the pur-

pose of such checking is defeated. Another impor tant

consideration for credential-based schemes is which

biometrics will be stored on the credential itself, espe-

cially considering space limitations and data transfer

rates of the card. This may constrain the number,

types, and formats of biometric data to be held. For

example, some image data (even compressed) may be

too large to be feasibly considered, or if used, may

further limit the inclusion of other biometr ics. If

ﬁngerprint data are to be included, the number and

selection of ﬁngers must be determined.

Most registered traveler systems use 1:1 biometric

veriﬁcation; however, it is possible to use a 1:N identi-

ﬁcation technology (e.g., iris recognition). In this case,

no claim of identity is made. The participant merely

presents his or her iris(es) at the kiosk and this is

matched against all other participants’ records, result-

ing in an identiﬁcation (identity returned as a result of

a match) or a no-match. This is usually performed

using a central server model to avoid the need to

duplicate the datab ase and protect all copies.

Today’s systems are generally built around service-

oriented architectures (SOA) taking advantage of the

internet, existing SOA tools, and the many beneﬁts of

this architecture. These include service requester/pro-

vider decoupling, modularity, scalability, and compo-

nent reuse. It is the basis of most large enterprise

architectures and supports business process orchestra-

tion (BPO) workﬂow implementation, usually as part

of an enterprise service bus (ESB).

Interoperability

In a nonfederated, single operator, closed RT system,

interoperability is not generally an issue. However, in a

federated system, this is critical as the various system

components must be able to properly function and

interact with one another. Areas in which interopera-

bility are most critical include:



Intrasystem (inter-subsystem) interfaces



Card edge and data model



Security

Examples of intersubsystem interfaces include

those between an enrollment station/system and the

central Identity Management System (IDMS), between

the IDMS and the STA/adjudication agency, and

between the ID MS and the veriﬁcation station/system.

The enrollment system must transmit collected ‘‘en-

rollment packages’’ to the IDMS for processing. The

data and messaging formats as well as the communica-

tion protocols must therefore be deﬁned. This includes

the format of the biometric data. It is preferred that the

submitted biometric information be in raw image for-

mat with minimal compression; however, some pre-

processing and compression are usually required. For

example, ﬁngerprint data are normally transferred as

three ‘‘slap’’ images in ANSI/NIST ITL1–2000/7 Type-

14 record format using WSQ compression [5]. Mes-

saging protocols are often Web services based, using a

‘‘SOAP over HTTP’’ XML-based implementation. In

addition to the basic set of messages required to per-

form an enrollment, additional messaging is required

to handle a host of error conditions and administrative

needs. These include those related to updates, fees, and

revocation.

With respect to an interoperable credential, the

challenge in a federated system is that a credential

produced by one service provider can be reliably and

securely read and veriﬁed by a different provider. This

generally requires a common form factor (e.g., ISO

card), a common ‘‘card edge’’ or card interface/com-

mand set, and a common data model. The card appli-

cation must be accessible and the security mechanisms

usable by all authorized entities. A good model for this

is the US PIV program already mentioned and the

associated technical guidance, most notably NIST

SP800–73 [6]. As an alternative, systems can leverage

the e-Passport as an inte roperable, biometrically-en-

abled credential, w ithout the lost and logistics of issu-

ing another. Common biometric data formats are also

critical for interoperable use across multip le airport

kiosks. For example , ﬁngerprint data may be stored

as ISO/IEC 19794–2 minutiae templates [7]. See also

the chapter on Standardization for more information

on biometric data interchange formats and technical

interfaces.

Security is important in all RT systems, but

becomes a bit trickier in federated systems due to the

key management challenges. The intersubsystem mes-

sages should be signed and either encrypted or passed

via an encrypted channel (i.e., SSL/TLS) using stan-

dard cryptographic protocols. Biometrics on a creden-

tial can be protected by one of the following means:

PIN protection, biometric data encry ption, and (card/

reader) mutual authentication. In all the cases, the

biometrics should be digitally signed either directly or

Registered Traveler

1115

via a container hashing/signing scheme such as that

used by ICAO for the ePassports.

Example Systems

This section takes a look at a few example registered

traveler system implementations.

Privium

An early, and successful showcase, registered traveler

program is the Privium system that was ﬁrst intro-

duced in 2002 at Schiphol airpor t in Amsterdam (fol-

lowing a one-year pilot), where participants are

charged €99 for the privilege of bypassing the long

queues at immigration (passport control).

This is a credential-based system where the iris data

are stored on a smartcard issued to the participant. The

enrolled iris data are not stored in a central database –

only on the card, which also contains passport data.

Any temporary use of this data is immediately pur-

ged after use to comply with Dutch privacy laws.

Enrollment includes a background check. At the Pri-

vium veriﬁcation station, a 1:1 biometric match is

performed against the iris template stored on the

Privium card.

The program is available to anyone with a Europe-

an Economic Area (EEA) passport. It is said to cut the

time spent at passport control to 10–15 s and queue

time by up to 30 min [3]. Besides fast-track border

passages, a separate check-in zone and priority parking

are offered (Privium Plus). Participants may check in

at the business class desk regardless of the class of ticket

they hold. Online application and appointments

are available. Onsite registration takes 15–20 min

and includes inspection of identity documents, iris

enrollment, and instructions on system operation.

The Privium card is good for 4 years, but is renewed

annually [8].

UK IRIS

The UK Home Ofﬁce Border & Immigration Agency

introduced its Iris Recognition Immigration System

(IRIS) in March 2006, as a free service to the traveling

public both to enhance their experience and to reduce

manned immigration platforms. It is the ﬁrst phase of

the UK e-Borders’ initiative to modernize immigration

controls. Participation allows registered passengers to

enter the UK without queuing to see an immigration

ofﬁcer at passport control [9]. The intent is to enhance

both security and efﬁciency.

The Home Ofﬁce says ‘‘Successfully enrolled pas-

sengers can enter the United Kingdom through auto-

mated immigration control barriers after looking into

an iris recognition camera.’’ Like the Privium program,

IRIS uses iris recognition technology ‘‘because it is a

fast, secure, and fraud-resistant way to verify passen-

gers’ identities. This makes it an ideal biometric for

secure yet expedited clearance [9]’’. It is operational

at Heathrow, Gatwick, Manchester, and Birmingham

airports where enrollment rooms are provided. Enroll-

ment takes approximately ﬁve to ten minutes.

Installation followed a trial in 2002 at Heathrow in

which 200 selected passengers were enrolled. This was a

joint project by British Airports Authority, the Immi-

gration Service, British Airways, and Virgin Atlantic

Airways. Figure 2 shows an IRIS veriﬁcation station

(barrier) at a UK arrival hall. Note the inclusion of

multiple iris cam eras mounted at various heights.

No ﬁngerprint data are collected during IRIS

enrollment – just iris and facial images – although an

interview by an immigration ofﬁcial is conducted. No

credentials are issued. Participation is voluntary and a

marketing campaign is in place, targeting non-EEA

foreign nationals. This has been a very popular system

to date. As of Februar y 2007, 61,000 people had

registered. The original estimate when the program

was announced was t hat over 1 million would be

registered within the ﬁrst ﬁve years.

US Registered Traveler

The United States piloted a registered traveler program

in 2005 at ﬁve airports as part of a technology evalua-

tion. Based on the results (including the popularity of

the program which extended the original timeframe)

and one additional private installation, a broader in-

teroperable, national pilot system was deployed in late

2006. The US RT scheme is a fully fee-based public-

private partnership. It uses a credential-based, feder-

ated architecture in which serv ice providers contract

with sponsors (airports/airlines) to operate the system.

A central IDMS operated by the American Associa-

tion of Airport Executives (AAAE) performs the func-

tions identiﬁed in Fig. 1. The Transportation Security

1116

Registered Traveler

Administration oversees the program and performs all

eligibility adjudications.

As a federated system, an interoperability speciﬁca-

tion was developed by a group called the Registered

Traveler Interoperability Consortium (RTIC). This

group, which included airport operators, technology

vendors, and system integrators with participation

from the TSA, developed the speciﬁcation over a

4 month period [10]. The TSA developed the program

‘‘to provide expedited security screening for passengers

who volunteer to undergo a TSA-conducted security

threat assessment (STA) in order to conﬁrm that they

do not pose or are not suspected of posing a threat to

transportation or national security [2].’’ The process

generally follows that described in the ‘‘Process’’

section earlier.

By December 2008, 20 airports had deployed the

RT system and 200,000 par ticipants had been enrolled,

and over 2 million trips made through RT lanes. At this

point, seven vendors had qualiﬁed as service providers.

Participants can verify (against their RT card) using

either ﬁngerprint or iris recognition. Figure 3 depicts

one of the US RT airport installations.

Canpass/Nexus-Air

In 2002, the Canadian Customs and Revenue Agency

(CCRA) and Citizenship and Immigration Canada

piloted an ‘‘express lane’’ through customs and immi-

gration based on iris recognition. It is operational at

airports in eight of the largest Canadian cities. The

program allows preapproved low-risk air travelers to

clear customs and immigration by using a self-service

kiosk.

The goal was to streamline airport operations while

maintaining a safe and secure border.

Now run by the Canada Border Services Agency

(CBSA), this system was subsequently expanded via a

bilateral Canada/US agreement into the NEXUS-AIR

program which pre-clears travelers returning to the US

from all major Canadian airports. CANPASS likewise

pre-clears travelers returning from US (and some other

international) locations.

Self-service kiosks use iris recognition to verify

CANPASS membership. Through an agreement with

CATSA, NEXUS-AIR members may also use the prior-

ity la ne through the security screening checkpoint. In

2007, fees were $80 CDN. Key ﬁndings of a 2006 pilot

evaluation found that par ticipants were extremely

satisﬁed with the program and reported saving an

average of 27 minutes per passage. According to a

survey conducted by EKOS Research Associates, the

average NEXUS-Air participant enters Canada 12.8

times per year [11].

Others

RT systems have been implemented in other countries

besides those highlighted earlier. For example, Germany

has deployed a system in Frankfurt. Japan has recently

Registered Traveler. Figure 2 UK IRIS Barrier.

Registered Traveler

1117

announced an RT component to their Japan Biometrics

Identiﬁcation (Border) system. And the EU has been

investigating the possibility of an ‘‘international’’ RT

program.

Issues and Considerations

Although apparently popular and workable, some

issues and considerations exist with the establishment

and use of RT systems.

Usability encompasses a range of issues related to

ergonomics, accessibility, user interface, general ease of

use, universality, and social acceptance. Biometric sys-

tems are typically not a ‘‘one-size ﬁts all’’ arrangement,

and care must be taken in their design to make them as

usable as possible to the broadest possible use r popu-

lation. For example, nearly every biometric technology

has a ﬁnite failure to enroll rate and some schemes are

not able to be used by disabled individuals.

Privacy concerns also must be dealt with sensitively.

Systems must take privacy considerations into account

from the earliest point in system design and gover-

nance. Fortunate ly, this seems to be the case in the

examples noted earlier.

Criticism has been levied against RT schemes as

being a ‘‘pay to go to the head of the line’’ rather

than a security improvement program – a so-called

‘‘Lexus line’’. ‘‘Not everyone is comfortable with what

amounts to a two-tier system: some say it unfairly

disadvantages infrequent travellers, and may make

them susceptible to undue scrutiny [12].’’

Summary

Biometric-based registered traveler programs are not

only becoming more popular but also being proved to

be workable and to provide beneﬁts both to the imple-

menters (i.e., governments and airports) and to the

traveling public. Althoug h similar in many areas, a

variety of different schemes, processes, and architec-

tures are employed to implement these programs.

Biometrics are used both in the registration process,

as part of the eligibility determination, and in the

authentication process, during operational use to

verify identity as a precleared program member.

Related Entries

▶ Border Management Applications

▶ Iris Recognition at Airports and Border-Crossings

▶ Standardization

▶ System Design

Registered Traveler. Figure 3 US Registered Traveler System.

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Registered Traveler

References

1. Registered Traveler Forum: What is an RT Program? (undated,

online), http://www.registered-traveler-forum.com/

2. Transportation Security Administration: Registered Traveler

page: http://www.tsa.gov/what_we_do/rt/index.shtm

3. Taylor, R.: All Eyes on Airport Security. The Guardian, 29 April

2004, http://www.guardian.co.uk/travel/2004/apr/29/travelnews1

4. Federal Information Processing Standard (FIPS) 201–1, Personal

Identity Veriﬁcation (PIV) of Federal Employees and Contrac-

tors, March 2006, NIST, http://csrc.nist.gov/groups/SNS/piv/

index.html

5. ANSI/NIST ITL1–2000, Data Format for the Interchange of

Fingerpint, Facial, & Scar Mark and Tatoo (SMT) Information,

July 2000

6. NIST Special Publication 800–73–1, Interfaces for Personal Iden-

tity Veriﬁcation, April 2006, http://csrc.nist.gov/publications/

nistpubs/800–73–1/sp800–73–1v7-April20–2006.pdf

7. ISO/IEC 19794, Biometric Data Interchange Formats, Parts 1–10

8. Amsterdam Airport Schiphol, Privium Program website: http://

www.schiphol.nl/privium/privium.jsp

9. Home Ofﬁce, Border & Immigration Agency, IRIS project web-

site: http://www.ind.homeofﬁce.gov.uk/applying/iris/

10. Registered Traveler Interoperability Consortium, RTIC Techni-

cal Interoperability Speciﬁcation, Ver 1.2, 2 May 2007, http://

www.rtconsortium.org/

11. Canada Border Security Agency (CBSA), NEXUS Air Pilot Proj-

ect Evaluation Study, http://cbsa-asfc.gc.ca/agency-agence/

reports-rapports/ae-ve/2006/nexus_air-eng.html#note_1

12. Calder, S.: How to bypass passport queues and leap the UK

immigration hurdle in the blink of an eye. The Indepen-

dent, 13 Aug 2007, http://travel.independent.co.uk/biztravel/

article2872060.ece

Remote Authentication

JUDITH MARKOWITZ

J. Markowitz, Consultants, Chicago, IL, USA

Synonyms

e-authentication, Remote access (par tial); Remote

monitoring (partial); Remote veriﬁcation

Definition

As with any form of authentication, remote authenti-

cation involves the veriﬁcation of a person’s claim of

identity. What makes remote authentication different

is that it is performed on individuals located beyond

the physical boundaries of the organization – what

some call as the

▶ extended enterprise.

Remote authentication is distinct from contactless

and at-a-distance. Those two methods refer to the

absence of direct contact or proximity between the

individual being authenticated and a biometric sensor.

Their focus is on the physical relationship between the

individual and the sensor.

In contrast, remote authentication says nothing

about the proximity of the user to the input device.

Both the user and the device are outside the perimeter

of the enterprise and may involve contact, contactless,

or at-a-distance input of biometric samples.

Remote authentication is also distinct from remote

identiﬁcation. ‘‘Authentication’’ is a synonym for veri-

ﬁcation which means the individual has made a claim

of identity and the function of the biometric system is

to determine whether the claim is valid.

Introduction

Historically the boundaries of enterprises, whether

they were private corporations or government

agencies, were largely deﬁned by brick and mortar.

Anyone wanting to do business with the enterprise

would appear in person and their identity would be

validated in situ. The primary forms of remote access

were via wireline telephone and mail, and remote au-

thentication was performed by humans.

Today, communication, transactions, and access

to information are available to anyone who has any

kind of telephone or Web-enabled computing device.

This extended enterprise is an essential co mponent of

e-government and e-business which, in turn, are fueled

by the Internet, globalization, and the mobile revolu-

tion. Furthermore, the individuals accessing the enter-

prise remotely include employees as well as partners,

suppliers, customers, and the public. Furthermore,

enterprises must specify the policies and procedures

that govern the access granted to each of these indivi-

duals and groups.

Access to the extended enterpris e has become in-

creasingly electronic and dominated by automation,

including

▶ interactive voice response (IVR) systems,

email, chat, SMS, and Web sites.

The growth of remote access has exposed the failure

of ID + password/PIN security to prevent or even

attenuate unauthorized access to personal data. There

has been a global escalation of identity theft and the

perpetration of new types of fraud [1]. In response,

security-enhancing regulations have been promulgated

Remote Authentication

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