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Before the Subcommittee on Aviation, Committee on Transportation and 
Infrastructure, House of Representatives:

United States General Accounting Office:


For Release on Delivery Expected at 10:00 a.m. EDT:

Wednesday, May 19, 2004:


Challenges in Using Biometric Technologies:

Statement of Keith A. Rhodes, Chief Technologist, 
Applied Research and Methods:


GAO Highlights:

Highlights of GAO-04-785T, a testimony before the Subcommittee on 
Aviation, Committee on Transportation and Infrastructure, House of 

Why GAO Did This Study:
One of the primary functions of any security system is the control of 
people moving into or out of protected areas, such as physical 
buildings, information systems, and our national border. Technologies 
called biometrics can automate the identification of people by one or 
more of their distinct physical or behavioral characteristics. The term 
biometrics covers a wide range of technologies that can be used to 
verify identity by measuring and analyzing human characteristics—
relying on attributes of the individual instead of things the 
individual may have or know. Since the September 11, 2001, terrorist 
attacks, laws have been passed that require a more extensive use of 
biometric technologies in the federal government.

In 2002, GAO conducted a technology assessment on the use of biometrics 
for border security. GAO was asked to testify about the issues that it 
raised in the report, the current state of the technology, and the 
application of biometrics to aviation security.

What GAO Found:

Biometric technologies are available today that can be used for 
aviation security. Biometric technologies vary in complexity, 
capabilities, and performance, and can be used to verify or establish a 
person’s identity. Leading biometric technologies include facial 
recognition, fingerprint recognition, hand geometry, and iris 
recognition. The Federal Aviation Administration (FAA), and 
subsequently, the Department of Homeland Security (DHS) and the 
Transportation Security Administration (TSA), has been examining the 
use of biometrics for aviation security for several years. TSA has 
three current pilot projects that will study the use of biometrics to 
enhance aviation security: the Transportation Worker Identification 
Credential (TWIC), registered traveler, and an access control pilot 
program designed to secure sensitive areas of an airport.

It is important to bear in mind that effective security cannot be 
achieved by relying on technology alone. Technology and people must 
work together as part of an overall security process. Weaknesses in any 
of these areas diminish the effectiveness of the security process. The 
security process needs to account for limitations in biometric 
technology. For example, some people cannot enroll in a biometrics 
system because they lack the appropriate body part. Similarly, errors 
sometimes occur during matching operations. Exception processing that 
is not as good as biometric-based primary processing could be exploited 
as a security hole. Further, non-technological processes for enrollment 
are critical to the success of a biometrics-based identity management 
system. Before a person is granted a biometric credential, the issuing 
authority needs to assure itself that the person is eligible to receive 
such a credential.

We have found that three key considerations need to be addressed before 
a decision is made to design, develop, and implement biometrics into a 
security system:

1. Decisions must be made on how the technology will be used.
2. A detailed cost-benefit analysis must be conducted to determine that 
the benefits gained from a system outweigh the costs.
3. A trade-off analysis must be conducted between the increased 
security, which the use of biometrics would provide, and the effect on 
areas such as privacy and convenience.

Security concerns need to be balanced with practical cost and 
operational considerations as well as political and economic interests. 
A risk management approach can help federal agencies identify and 
address security concerns. To develop security systems with biometrics,
the high-level goals of these systems need to be defined, and the 
concept of operations that will embody the people, process, and 
technologies required to achieve these goals needs to be developed. 
With these answers, the proper role of biometric technologies in 
aviation security can be determined.

To view the full product, including the scope and methodology, click on 
the link above. For more information, contact Keith Rhodes at (202) 
512-6412 or

[End of section]

Mr. Chairman and Members of the Subcommittee:

I appreciate the opportunity to participate in today's hearing on the 
use of biometrics for aviation security. The security of the U.S. 
commercial aviation system has been a long-standing concern. Following 
the September 11, 2001, terrorist attacks, virtually all aviation 
security responsibilities now reside within the Department of Homeland 
Security (DHS) and its Transportation Security Administration (TSA). 
These responsibilities include the conduct of passenger and baggage 
screening and overseeing security measures for airports, commercial 
aircraft, air cargo, and general aviation. DHS and TSA have undertaken 
several initiatives to improve aviation security. Some efforts, 
including those involving access control to secure areas of an airport 
and identifying travelers, include biometric technologies.

One of the primary functions of any security system is the control of 
people moving into or out of protected areas, such as physical 
buildings, information systems, and our national border. People are 
identified by three basic means: by something they know, something they 
have, or something they are. People and systems regularly use these 
means to identify people in everyday life. For example, members of a 
community routinely recognize one another by how they look or how their 
voices sound--by something they are. Automated teller machines (ATM) 
recognize customers from their presentation of a bank card--something 
they have--and their entering a personal identification number (PIN)--
something they know. Using keys to enter a locked building is another 
example of using something you have. More secure systems may combine 
two or more of these approaches.

Technologies called biometrics can automate the identification of 
people by one or more of their distinct physical or behavioral 
characteristics--by something they are. The term biometrics covers a 
wide range of technologies that can be used to verify identity by 
measuring and analyzing human characteristics. Biometrics 
theoretically represent a more effective approach to security because 
each person's characteristics are thought to be distinct and, when 
compared with identification cards and passwords, are less easily lost, 
stolen, counterfeited, or otherwise compromised.

As requested, I will provide an overview of biometric technologies that 
are currently available, describe some of the current uses of these 
technologies, and discuss the issues and challenges associated with the 
implementation of biometrics. My testimony today is based on a body of 
work we completed in 2002 that examined the use of biometrics for 
border control. In that report, we discussed the maturity of several 
biometric technologies, the possible implementation of these 
technologies in current border control processes, and the policy 
implications and key considerations for using these 
technologies.[Footnote 1] We also researched selected prior and current 
TSA and DHS biometrics initiatives and summarize them in this 
statement. We performed our work in accordance with generally accepted 
government auditing standards.

Biometric Technologies for Personal Identification:

When used for personal identification, biometric technologies measure 
and analyze human physiological and behavioral characteristics. 
Identifying a person's physiological characteristics is based on direct 
measurement of a part of the body--fingertips, hand geometry, facial 
geometry, and eye retinas and irises. The corresponding biometric 
technologies are fingerprint recognition, hand geometry, and facial, 
retina, and iris recognition. Identifying behavioral characteristics is 
based on data derived from actions, such as speech and signature, the 
corresponding biometrics being speaker recognition and signature 
recognition. Unlike conventional identification methods that use 
something you have, such as an identification card to gain access to a 
building, or something you know, such as a password to log on to a 
computer system, these characteristics are integral to something you 

How Biometric Technologies Work:

Biometric technologies vary in complexity, capabilities, and 
performance, but all share several elements. Biometric identification 
systems are essentially pattern recognition systems. They use 
acquisition devices such as cameras and scanning devices to capture 
images, recordings, or measurements of an individual's characteristics 
and computer hardware and software to extract, encode, store, and 
compare these characteristics. Because the process is automated, 
biometric decision-making is generally very fast, in most cases taking 
only a few seconds in real time.

Depending on the application, biometric systems can be used in one of 
two modes: verification or identification. Verification--also called 
authentication--is used to verify a person's identity--that is, to 
authenticate that individuals are who they say they are. Identification 
is used to establish a person's identity--that is, to determine who a 
person is. Although biometric technologies measure different 
characteristics in substantially different ways, all biometric systems 
start with an enrollment stage followed by a matching stage that can 
use either verification or identification.


In enrollment, a biometric system is trained to identify a specific 
person. The person first provides an identifier, such as an identity 
card. The biometric is linked to the identity specified on the 
identification document. He or she then presents the biometric (e.g., 
fingertips, hand, or iris) to an acquisition device. The distinctive 
features are located and one or more samples are extracted, encoded, 
and stored as a reference template for future comparisons. Depending on 
the technology, the biometric sample may be collected as an image, a 
recording, or a record of related dynamic measurements. How biometric 
systems extract features and encode and store information in the 
template is based on the system vendor's proprietary algorithms. 
Template size varies depending on the vendor and the technology. 
Templates can be stored remotely in a central database or within a 
biometric reader device itself; their small size also allows for 
storage on smart cards or tokens.

Minute changes in positioning, distance, pressure, environment, and 
other factors influence the generation of a template. Consequently, 
each time an individual's biometric data are captured, the new template 
is likely to be unique. Depending on the biometric system, a person may 
need to present biometric data several times in order to enroll. Either 
the reference template may then represent an amalgam of the captured 
data or several enrollment templates may be stored. The quality of the 
template or templates is critical in the overall success of the 
biometric application. Because biometric features can change over time, 
people may have to reenroll to update their reference template. Some 
technologies can update the reference template during matching 

The enrollment process also depends on the quality of the identifier 
the enrollee presents. The reference template is linked to the identity 
specified on the identification document. If the identification 
document does not specify the individual's true identity, the reference 
template will be linked to a false identity.


In verification systems, the step after enrollment is to verify that a 
person is who he or she claims to be (i.e., the person who enrolled). 
After the individual provides an identifier, the biometric is 
presented, which the biometric system captures, generating a trial 
template that is based on the vendor's algorithm. The system then 
compares the trial biometric template with this person's reference 
template, which was stored in the system during enrollment, to 
determine whether the individual's trial and stored templates match.

Verification is often referred to as 1:1 (one-to-one) matching. 
Verification systems can contain databases ranging from dozens to 
millions of enrolled templates but are always predicated on matching an 
individual's presented biometric against his or her reference template. 
Nearly all verification systems can render a match-no-match decision in 
less than a second. A system that requires employees to authenticate 
their claimed identities before granting them access to secure 
buildings or to computers is a verification application.


In identification systems, the step after enrollment is to identify who 
the person is. Unlike verification systems, no identifier is provided. 
To find a match, instead of locating and comparing the person's 
reference template against his or her presented biometric, the trial 
template is compared against the stored reference templates of all 
individuals enrolled in the system. Identification systems are referred 
to as 1:N (one-to-N, or one-to-many) matching because an individual's 
biometric is compared against multiple biometric templates in the 
system's database.

There are two types of identification systems: positive and negative. 
Positive identification systems are designed to ensure that an 
individual's biometric is enrolled in the database. The anticipated 
result of a search is a match. A typical positive identification system 
controls access to a secure building or secure computer by checking 
anyone who seeks access against a database of enrolled employees. The 
goal is to determine whether a person seeking access can be identified 
as having been enrolled in the system.

Negative identification systems are designed to ensure that a person's 
biometric information is not present in a database. The anticipated 
result of a search is a nonmatch. Comparing a person's biometric 
information against a database of all who are registered in a public 
benefits program, for example, can ensure that this person is not 
"double dipping" by using fraudulent documentation to register under 
multiple identities.

Another type of negative identification system is a watch list system. 
Such systems are designed to identify people on the watch list and 
alert authorities for appropriate action. For all other people, the 
system is to check that they are not on the watch list and allow them 
normal passage. The people whose biometrics are in the database in 
these systems may not have provided them voluntarily. For instance, for 
a surveillance system, the biometric may be faces captured from mug 
shots provided by a law enforcement agency.

Matches Are Based on Threshold Settings:

No match is ever perfect in either a verification or an identification 
system, because every time a biometric is captured, the template is 
likely to be unique. Therefore, biometric systems can be configured to 
make a match or no-match decision, based on a predefined number, 
referred to as a threshold, that establishes the acceptable degree of 
similarity between the trial template and the enrolled reference 
template. After the comparison, a score representing the degree of 
similarity is generated, and this score is compared to the threshold to 
make a match or no-match decision. Depending on the setting of the 
threshold in identification systems, sometimes several reference 
templates can be considered matches to the trial template, with the 
better scores corresponding to better matches.

Leading Biometric Technologies:

A growing number of biometric technologies have been proposed over the 
past several years, but only in the past 5 years have the leading ones 
become more widely deployed. Some technologies are better suited to 
specific applications than others, and some are more acceptable to 
users. We describe seven leading biometric technologies:

* Facial Recognition:

* Fingerprint Recognition:

* Hand Geometry:

* Iris Recognition:

* Retina Recognition:

* Signature Recognition:

* Speaker Recognition:

Facial Recognition:

Facial recognition technology identifies people by analyzing features 
of the face that are not easily altered--the upper outlines of the eye 
sockets, the areas around the cheekbones, and the sides of the mouth. 
The technology is typically used to compare a live facial scan to a 
stored template, but it can also be used in comparing static images 
such as digitized passport photographs. Facial recognition can be used 
in both verification and identification systems. In addition, because 
facial images can be captured from video cameras, facial recognition is 
the only biometric that can be used for surveillance purposes.

Fingerprint Recognition:

Fingerprint recognition is one of the best known and most widely used 
biometric technologies. Automated systems have been commercially 
available since the early 1970s, and at the time of our study, we found 
there were more than 75 fingerprint recognition technology companies. 
Until recently, fingerprint recognition was used primarily in law 
enforcement applications.

Fingerprint recognition technology extracts features from impressions 
made by the distinct ridges on the fingertips. The fingerprints can be 
either flat or rolled. A flat print captures only an impression of the 
central area between the fingertip and the first knuckle; a rolled 
print captures ridges on both sides of the finger.

An image of the fingerprint is captured by a scanner, enhanced, and 
converted into a template. Scanner technologies can be optical, 
silicon, or ultrasound technologies. Ultrasound, while potentially the 
most accurate, has not been demonstrated in widespread use. In 2002, we 
found that optical scanners were the most commonly used. During 
enhancement, "noise" caused by such things as dirt, cuts, scars, and 
creases or dry, wet, or worn fingerprints is reduced, and the 
definition of the ridges is enhanced. Approximately 80 percent of 
vendors base their algorithms on the extraction of minutiae points 
relating to breaks in the ridges of the fingertips. Other algorithms 
are based on extracting ridge patterns.

Hand Geometry:

Hand geometry systems have been in use for almost 30 years for access 
control to facilities ranging from nuclear power plants to day care 
centers. Hand geometry technology takes 96 measurements of the hand, 
including the width, height, and length of the fingers; distances 
between joints; and shapes of the knuckles.

Hand geometry systems use an optical camera and light-emitting diodes 
with mirrors and reflectors to capture two orthogonal two-dimensional 
images of the back and sides of the hand. Although the basic shape of 
an individual's hand remains relatively stable over his or her 
lifetime, natural and environmental factors can cause slight changes. 
The shape and size of our hands are reasonably diverse, but are not 
highly distinctive. Thus, hand geometry is not suitable for performing 
identification matches.

Iris Recognition:

Iris recognition technology is based on the distinctly colored ring 
surrounding the pupil of the eye. Made from elastic connective tissue, 
the iris is a very rich source of biometric data, having approximately 
266 distinctive characteristics. These include the trabecular meshwork, 
a tissue that gives the appearance of dividing the iris radially, with 
striations, rings, furrows, a corona, and freckles. Iris recognition 
technology uses about 173 of these distinctive characteristics. These 
characteristics, which are formed during the 8TH month of gestation, 
reportedly remain stable throughout a person's lifetime, except in 
cases of injury. Iris recognition can be used in both verification and 
identification systems.

Iris recognition systems use a small, high-quality camera to capture a 
black and white, high-resolution image of the iris. The systems then 
define the boundaries of the iris, establish a coordinate system over 
the iris, and define the zones for analysis within the coordinate 

Retina Recognition:

Retina recognition technology captures and analyzes the patterns of 
blood vessels on the thin nerve on the back of the eyeball that 
processes light entering through the pupil. Retinal patterns are highly 
distinctive traits. Every eye has its own totally unique pattern of 
blood vessels; even the eyes of identical twins are distinct. Although 
each pattern normally remains stable over a person's lifetime, it can 
be affected by diseases such as glaucoma, diabetes, high blood 
pressure, and autoimmune deficiency syndrome.

The fact that the retina is small, internal, and difficult to measure 
makes capturing its image more difficult than most biometric 
technologies. An individual must position the eye very close to the 
lens of the retina-scan device, gaze directly into the lens, and remain 
perfectly still while focusing on a revolving light while a small 
camera scans the retina through the pupil. Any movement can interfere 
with the process and can require restarting. Enrollment can easily take 
more than a minute.

Signature Recognition:

Signature recognition authenticates identity by measuring handwritten 
signatures. The signature is treated as a series of movements that 
contain unique biometric data, such as personal rhythm, acceleration, 
and pressure flow. Unlike electronic signature capture, which treats 
the signature as a graphic image, signature recognition technology 
measures how the signature is signed.

In a signature recognition system, a person signs his or her name on a 
digitized graphics tablet or personal digital assistant. The system 
analyzes signature dynamics such as speed, relative speed, stroke 
order, stroke count, and pressure. The technology can also track each 
person's natural signature fluctuations over time. The signature 
dynamics information is encrypted and compressed into a template.

Speaker Recognition:

Differences in how different people's voices sound result from a 
combination of physiological differences in the shape of vocal tracts 
and learned speaking habits. Speaker recognition technology uses these 
differences to discriminate between speakers.

During enrollment, speaker recognition systems capture samples of a 
person's speech by having him or her speak some predetermined 
information into a microphone a number of times. This information, 
known as a passphrase, can be a piece of information such as a name, 
birth month, birth city, or favorite color or a sequence of numbers. 
Text independent systems are also available that recognize a speaker 
without using a predefined phrase. This phrase is converted from analog 
to digital format, and the distinctive vocal characteristics, such as 
pitch, cadence, and tone, are extracted, and a speaker model is 
established. A template is then generated and stored for future 

Speaker recognition can be used to verify a person's claimed identity 
or to identify a particular person. It is often used where voice is the 
only available biometric identifier, such as telephone and call 

Accuracy of Biometric Technology:

Biometrics is a young technology, having only recently reached the 
point at which basic matching performance can be acceptably deployed. 
It is necessary to analyze several metrics to determine the strengths 
and weaknesses of each technology and vendor for a given application.

The three key performance metrics are false match rate (FMR), false 
nonmatch rate (FNMR), and failure to enroll rate (FTER). A false match 
occurs when a system incorrectly matches an identity, and FMR is the 
probability of individuals being wrongly matched. In verification and 
positive identification systems, unauthorized people can be granted 
access to facilities or resources as the result of incorrect matches. 
In a negative identification system, the result of a false match may be 
to deny access. For example, if a new applicant to a public benefits 
program is falsely matched with a person previously enrolled in that 
program under another identity, the applicant may be denied access to 

A false nonmatch occurs when a system rejects a valid identity, and 
FNMR is the probability of valid individuals being wrongly not matched. 
In verification and positive identification systems, people can be 
denied access to some facility or resource as the result of a system's 
failure to make a correct match. In negative identification systems, 
the result of a false nonmatch may be that a person is granted access 
to resources to which he or she should be denied. For example, if a 
person who has enrolled in a public benefits program under another 
identity is not correctly matched, he or she will succeed in gaining 
fraudulent access to benefits.

False matches may occur because there is a high degree of similarity 
between two individuals' characteristics. False nonmatches occur 
because there is not a sufficiently strong similarity between an 
individual's enrollment and trial templates, which could be caused by 
any number of conditions. For example, an individual's biometric data 
may have changed as a result of aging or injury. If biometric systems 
were perfect, both error rates would be zero. However, because 
biometric systems cannot identify individuals with 100 percent 
accuracy, a trade-off exists between the two.

False match and nonmatch rates are inversely related; they must, 
therefore, always be assessed in tandem, and acceptable risk levels 
must be balanced with the disadvantages of inconvenience. For example, 
in access control, perfect security would require denying access to 
everyone. Conversely, granting access to everyone would result in 
denying access to no one. Obviously, neither extreme is reasonable, and 
biometric systems must operate somewhere between the two.

For most applications, how much risk one is willing to tolerate is the 
overriding factor, which translates into determining the acceptable 
FMR. The greater the risk entailed by a false match, the lower the 
tolerable FMR. For example, an application that controlled access to a 
secure area would require that the FMR be set low, which would result 
in a high FNMR. However, an application that controlled access to a 
bank's ATM might have to sacrifice some degree of security and set a 
higher FMR (and hence a lower FNMR) to avoid the risk of irritating 
legitimate customers by wrongly rejecting them. As figure 1 shows, 
selecting a lower FMR increases the FNMR. Perfect security would 
require setting the FMR to 0, in which case the FNMR would be 1. At the 
other extreme, setting the FNMR to 0 would result in an FMR of 1.

Vendors often use equal error rate (EER), an additional metric derived 
from FMR and FNMR, to describe the accuracy of their biometric systems. 
EER refers to the point at which FMR equals FNMR. Setting a system's 
threshold at its EER will result in the probability that a person is 
falsely matched equaling the probability that a person is falsely not 
matched. However, this statistic tends to oversimplify the balance 
between FMR and FNMR, because in few real-world applications is the 
need for security identical to the need for convenience.

Figure 1: The General Relationship between FMR and FNMR:

[See PDF for image]

Source: GAO.

Note: Equal error rate is the point at which FMR equals FNMR.

[End of figure]

FTER is a biometric system's third critical accuracy metric. FTER 
measures the probability that a person will be unable to enroll. 
Failure to enroll (FTE) may stem from an insufficiently distinctive 
biometric sample or from a system design that makes it difficult to 
provide consistent biometric data. The fingerprints of people who work 
extensively at manual labor are often too worn to be captured. A high 
percentage of people are unable to enroll in retina recognition systems 
because of the precision such systems require. People who are mute 
cannot use voice systems, and people lacking fingers or hands from 
congenital disease, surgery, or injury cannot use fingerprint or hand 
geometry systems. Although between 1 and 3 percent of the general 
public does not have the body part required for using any one biometric 
system, they are normally not counted in a system's FTER.

Using Multiple Biometrics:

Because biometric systems based solely on a single biometric may not 
always meet performance requirements, the development of systems that 
integrate two or more biometrics is emerging as a trend. Multiple 
biometrics could be two types of biometrics, such as combining facial 
and iris recognition. Multiple biometrics could also involve multiple 
instances of a single biometric, such as 1, 2, or 10 fingerprints, 2 
hands, and 2 eyes. One prototype system integrates fingerprint and 
facial recognition technologies to improve identification. A 
commercially available system combines face, lip movement, and speaker 
recognition to control access to physical structures and small office 
computer networks. Depending on the application, both systems can 
operate for either verification or identification. Experimental results 
have demonstrated that the identities established by systems that use 
more than one biometric could be more reliable, be applied to large 
target populations, and improve response time.

Standards for Biometric Technology:

Identifying, exchanging, and integrating information from different and 
perhaps unfamiliar sources and functions are essential to an effective 
biometrics application. Without standards, system developers may need 
to define in detail the precise steps for exchanging information, a 
potentially complex, time-consuming, and expensive process. Progress 
has been made in developing biometrics standards. However, the majority 
of biometric devices and their software are still proprietary in many 
respects. For example, the method for extracting features from a 
biometric sample, such as a fingerprint, differs among most, if not 
all, vendors. Devices from company A do not necessarily work compatibly 
with devices from companies B and C.

Standards such as the National Institute of Science and Technology's 
(NIST) Common Biometric Exchange File Format (CBEFF) facilitate data 
exchange between different system components and simplify the 
integration of software and hardware from different vendors. The 
wavelet scalar quantization (WSQ) gray-scale fingerprint image 
compression algorithm is the standard for exchanging fingerprint images 
within the criminal justice system. Similarly, the Joint Photographic 
Experts Group (JPEG) has established an image compression standard that 
is designed to facilitate the transfer of images for facial recognition 

The American Association for Motor Vehicle Administration (AAMVA) 
included a format for fingerprint minutiae data in its Driver License 
and Identification Standard, which provides a uniform means to identify 
issuers and holders of driver's licenses in the United States and 
Canada. However, the standard still allows for including data in a 
vendor-specific format. Biometric templates, which capture only the 
critical data needed to make a match, are small, but the template one 
vendor uses cannot generally be used by another for some biometric 
technologies, such as fingerprints. Without the creation and industry 
adoption of a biometric template standard, it could be necessary to 
store the larger biometric sample as well as the biometric template for 
each user during enrollment. Last year, the International Civil 
Aviation Organization (ICAO) New Technologies Working Group concluded 
that the only reliable globally interoperable method for exchanging 
face, fingerprint, or iris biometric data was the storage of the 
respective image. ICAO is studying the use of biometrics in machine-
readable travel documents, such as passports and visas.

In November 2001, the executive board of the International Committee 
for Information Technology Standards (INCITS) established a technical 
committee for biometrics for the rapid development and approval of 
formal national and international generic biometric standards. Four 
task groups were created to conduct the work. The first task group is 
focused on the standardization of the content, meaning, and 
representation of biometric data interchange formats. This task group 
is working on formats for representing fingerprints, faces, irises, 
hand geometry, and signatures. The second task group covers the 
standardization of interfaces and interactions between biometric 
components and subsystems. CBEFF is an example of an interface 
standard. The third task group focuses on the development of biometric 
application profiles. It currently has projects in the areas of border 
crossings, transportation workers, and point of sale. The fourth task 
group handles the standardization of biometric performance metric 
definitions and calculations, approaches to test performance, and 
requirements for reporting the results of these tests.

Using Biometrics for Aviation Security:

The Federal Aviation Administration (FAA), and subsequently, DHS and 
TSA, has been examining the use of biometrics for aviation security for 
several years. In 2001, the FAA and the Department of Defense 
Counterdrug Technology Development Program Office co-chaired the 
Aviation Security Biometrics Working Group (ASBWG). They examined the 
use of biometrics in four aviation security applications: (1) identity 
verification of employees and ensuring that access to secured areas 
within an airport is restricted to authorized personnel; (2) protection 
of public areas in and around airports using surveillance; (3) identity 
verification of passengers boarding aircraft; and (4) identity 
verification of flight crews prior to and during a flight. 
Subsequently, in 2002, TSA contracted with the International Biometric 
Group to evaluate the use of biometrics for automated surveillance 
within airports, trusted traveler cards for passengers, and identity 
verification of employees for access control in airports.[Footnote 2]

Since the 2001 terrorist attacks, the Congress has directed a greater 
use of biometrics. For example, the Aviation and Transportation 
Security Act (ATSA), which created TSA and mandated several actions 
designed to enhance aviation security, includes several provisions 
regarding the use of biometrics for applications, such as perimeter 
security or access control.[Footnote 3]

Access Control:

Biometric systems have long been used to complement or replace badges 
and keys in controlling access to entire facilities or specific areas 
within a facility. The entrances to more than half the nuclear power 
plants in the United States employ hand geometry systems. Further, 
recent reductions in the price of biometric hardware have spurred 
logical access control applications. Fingerprint, iris, and speaker 
recognition are replacing passwords to authenticate individuals 
accessing computers and networks. The Office of Legislative Counsel of 
the U.S. House of Representatives, for example, is using an iris 
recognition system to protect confidential files and working documents. 
Other federal agencies, including the Department of Defense, Department 
of Energy, and Department of Justice, as well as the intelligence 
community, are adopting similar technologies.

We have previously reported on the critical need to limit access to 
secure airport areas. In 2000, we reported on the ability of our 
special agents to use fictitious law enforcement badges and credentials 
to gain access to secure areas of two commercial airports.[Footnote 4] 
The agents, who had been issued tickets and boarding passes, were not 
screened through magnetometers at the security checkpoints nor was 
their baggage inspected. This vulnerability could have allowed our 
agents to carry weapons, explosives, or other dangerous objects onto an 

Since 1991, San Francisco International Airport has used hand geometry 
devices in conjunction with identification cards to protect secure 
areas of the airport, such as the tarmac and loading gates. Last year, 
Toledo (Ohio) Express Airport also installed hand geometry devices to 
ensure that only authorized personnel can gain access to critical areas 
of the airport.

FAA has conducted several tests and pilots of biometrics for access 
control to secure areas of airports. In 1998, FAA funded an operational 
test at Chicago's O'Hare International Airport involving smart cards 
and fingerprint recognition to identify employees of motor carrier and 
air cargo companies at access control points to cargo areas. Further, 
in 2001, FAA conducted tests of hand geometry and fingerprint and 
facial recognition technologies for employee access control at 

TSA has two current efforts examining the use of biometrics for access 
control. The Transportation Worker Identification Credential (TWIC) is 
designed to be a common credential for all transportation workers 
requiring unescorted physical access to secure areas of the national 
transportation system, such as airports, seaports, and railroad 
terminals. It will also be used to help secure logical access to 
computers, networks, and applications. The program was developed in 
response to ATSA and the Maritime Transportation Security Act of 2002 
and will include the use of biometrics to provide a positive match of a 
credential for up to 6 million transportation workers across the United 
States.[Footnote 5] The TWIC program is designed as an identity 
authentication tool for individual facilities and to provide assurance 
that individuals with a TWIC card have undergone a threat assessment to 
ensure that they are not known terrorists. Individual facilities will 
be able to use the TWIC cards to control access to secure areas to only 
authorized individuals.

Last week, TSA issued a request for proposal for a TWIC prototype to 
determine the performance of TWIC as an access control tool. For the 
prototype, TSA will be examining the use of at least fingerprint and 
iris recognition. During a technology evaluation last year, TSA 
evaluated six card technologies and determined that an integrated 
circuit chip smart card was the most appropriate for the TWIC card. As 
part of the prototype, TSA will also examine the use of cards with 2-
dimensional bar codes and optical stripes. The prototype phase is 
expected to last 7 months and will be conducted in Philadelphia, PA; 
Wilmington, DE; the ports of Long Beach and Los Angeles, CA; and the 14 
major port facilities in the state of Florida. TSA anticipates that up 
to 200,000 workers will be enrolled in the program. Following the 
prototype, TSA will make a decision on whether to proceed with 
implementation of the program.

Earlier this month, TSA announced an access control pilot program that 
will test various technologies, including biometrics, that are designed 
to ensure that only authorized personnel have access to non-passenger 
controlled areas. Developed in response to a section in ATSA that 
directed the establishment of pilot programs to test and evaluate 
technologies for providing access control to closed or secure areas of 
airports, the program will test fingerprint recognition at four 
airports and iris recognition at one airport.[Footnote 6] Boise Air 
Terminal/Gowen Field Airport, Southwest Florida International Airport, 
and Tampa International Airport will test fingerprint recognition to 
control vehicle access. Newark International Airport will test 
fingerprint recognition to allow only authorized persons into secure 
areas of the airport. T.F. Green State Airport (Providence, RI) will 
test iris recognition to control access to secure areas of the airport.

Registered Traveler:

The concept of a registered traveler program is to provide an expedited 
security screening for passengers who meet the eligibility criteria and 
who voluntarily provide personal information and clear a background 
check. ATSA permits TSA to "establish requirements to implement trusted 
passenger programs and use available technologies to expedite the 
security screening of passengers who participate in such programs, 
thereby allowing security screening personnel to focus on those 
passengers who should be subject to more extensive screening."[Footnote 

In 2002, we reviewed the policy and implementation issues associated 
with a registered traveler program.[Footnote 8] We identified four key 
questions that need to be addressed by the federal government before 
proceeding with such a program: (1) What criteria should be established 
to determine eligibility to apply for the program? (2) What kinds of 
background checks should be used to certify that applicants are 
eligible to enroll in the program, and who should perform these? (3) 
Which security-screening procedures should registered travelers 
undergo, and how should these differ from those used for unregistered 
travelers? and (4) To what extent do equity, privacy, and liability 
issues have to be resolved prior to program implementation?

In April 2004, TSA issued a combined solicitation synopsis for a 
registered traveler pilot program. TSA has evaluated the capabilities 
statements from about 40 proposals. TSA expects to award contracts for 
the pilot program in early June 2004. The pilot program will run for 
about 90 days at up to five airports. TSA expects to enroll up to 
10,000 travelers in the program using fingerprint and/or iris 
recognition. To enroll, travelers will submit biographic and biometric 
data at the selected airports. A security assessment will be conducted 
on the applicants to verify their eligibility for the program. TSA may 
use a TSA-issued card or an airline frequent flier card as an 
identifier to conduct biometric verification matches of registered 
travelers at airport security checkpoints. TSA is also considering the 
use of identification (1-to-many) matching to ascertain the identity of 
the registered traveler. Once registered travelers are identified, they 
will undergo an adjusted screening process, designed to expedite 
throughput for low-risk travelers.

Similar programs have been used for expediting border control 
processes. For example, the Immigration and Naturalization Service 
(INS) Passenger Accelerated Service System (INSPASS), a pilot program 
in place since 1993, has more than 45,000 frequent fliers enrolled at 
nine airports, and has admitted more than 300,000 travelers. It is open 
to citizens of the United States, Canada, Bermuda, and visa waiver 
program countries who travel to the United States on business three or 
more times a year.[Footnote 9] To participate, users provide a passport 
or travel document and submit two fingerprints and a hand geometry 
biometric. Once travelers successfully undergo a background screening 
and are enrolled, they can circumvent immigration procedures and lines. 
An INSPASS participant presents their hand geometry biometric at an 
airport kiosk for comparison against the reference template stored in a 
central database for that traveler. INSPASS has reduced the inspection 
time for participants to less than 15 seconds.

Airport Surveillance:

It has been suggested that facial recognition could be used in airports 
as a surveillance tool that could identify persons of interest without 
the subject's cooperation or knowledge. Key to such an effort is the 
availability of a database of biometric information of persons of 
interest (i.e., a watch list). Surveillance activities are often 
conducted by humans who are looking for persons of interest using 
closed-circuit televisions. However, because it is well understood that 
humans are limited in their ability to recognize individuals they are 
not familiar with, and that there are limits of human attention when 
conducting surveillance activities, facial recognition has been cited 
as a potential surveillance tool.

In 2001, the ASBWG found that facial recognition technology was not 
sufficiently mature to be relied upon for wide-area surveillance. 
Further, as we reported in 2002, one vendor conducted pilots using 
facial recognition technology to conduct surveillance at U.S. airports. 
For these pilots, video cameras were installed at the security 
checkpoints, near the magnetometers. From the pilots, it was learned 
that lighting was the primary factor in determining the performance of 
facial recognition.

Other Federal Biometric Applications:

There are two other primary uses of biometrics in the federal 
government: criminal identification and border security.

Criminal Identification:

Fingerprint identification has been used in law enforcement over the 
past 100 years and has become the de facto international standard for 
positively identifying individuals. The Federal Bureau of Investigation 
(FBI) has been using fingerprint identification since 1928. The first 
fingerprint recognition systems were used in law enforcement about 4 
decades ago.

The FBI's Integrated Automated Fingerprint Identification System 
(IAFIS) is an automated 10-fingerprint matching system that stores 
rolled fingerprints. The more than 40 million records in its criminal 
master file are connected electronically with all 50 states and some 
federal agencies. IAFIS was designed to handle a large volume of 
fingerprint checks against a large database of fingerprints. In 2002, 
we found that IAFIS processes, on average, approximately 48,000 
fingerprints per day and has processed as many as 82,000 in a single 
day. IAFIS's target response time for criminal fingerprints submitted 
electronically is 2 hours; for civilian fingerprint background checks, 
24 hours.

Border Security:

There are several uses of biometrics for border security in the United 
States and worldwide.[Footnote 10] Two notable examples are the INS 
Automated Biometric Fingerprint Identification System (IDENT) and the 
United States Visitor and Immigrant Status Indicator Technology (US-
VISIT) system.

INS began developing IDENT around 1990 to identify illegal aliens who 
are repeatedly apprehended trying to enter the United States illegally. 
INS's goal was to enroll virtually all apprehended aliens. IDENT can 
also identify aliens who have outstanding warrants or who have been 
deported. When such aliens are apprehended, a photograph and two index 
fingerprints are captured electronically and queried against three 
databases. In 2002, IDENT had over 4.5 million entries. A fingerprint 
query of IDENT normally takes about 2 minutes.

Laws passed since the September 11, 2001, terrorist attacks require a 
more extensive use of biometrics for border control.[Footnote 11] The 
Attorney General and the Secretary of State jointly, through NIST are 
to develop a technology standard, including biometric identifier 
standards.[Footnote 12] When developed, this standard is to be used to 
verify the identity of persons applying for a U.S. visa for the purpose 
of conducting a background check, confirming identity, and ensuring 
that a person has not received a visa under a different name. Further, 
aliens are to be issued machine-readable, tamper-resistant visas and 
other travel and entry documents that use biometric identifiers. 
Similarly, equipment and software are to be installed at all ports of 
entry that can allow the biometric comparison and authentication of all 
U.S. visas and other travel and entry documents issued to aliens and 
machine-readable passports.

DHS is developing the US-VISIT system to address these requirements. 
The US-VISIT system currently uses IDENT technology to collect a 
photograph and two index fingerprints from travelers holding non-
immigrant visas. Travelers are initially enrolled either at a port of 
entry using US-VISIT entry procedures or at a U.S. consulate or embassy 
when they apply for their visa. US-VISIT entry procedures are currently 
in place at 115 airports and 14 seaports. By December 31, 2004, US-
VISIT is planned to be in place at the 50 busiest land ports of entry. 
By December 31, 2005, US-VISIT is planned to be in place at all 165 
land ports of entry. As of March 4, 2004, biometric data collection was 
in place at more than 80 visa-adjudicating posts. By October 2004, 
biometric data collection is expected to be in use at all 211 visa-
issuing embassies and consulates. By September 30, 2004, US-VISIT 
procedures will be expanded to include visitors traveling to the United 
States under the visa waiver program arriving at air and sea ports of 

Each time a visitor enters the United States at a port of entry 
employing US-VISIT entry procedures, the visitor's fingerprints will be 
matched against the reference fingerprints captured during enrollment. 
During enrollment and each subsequent visit, the biographic and 
biometric data of the visitor is compared to watch lists to assist the 
inspectors in making admissibility decisions. At one airport and one 
seaport, visitors are also expected to record their departure from the 
United States using an automated self-service kiosk that can scan the 
visitor's travel documents and capture the visitor's 
fingerprints.[Footnote 13]

Challenges and Issues in Using Biometrics:

While biometric technology is currently available and used in a variety 
of applications, questions remain regarding the technical and 
operational effectiveness of biometric technologies in large-scale 
applications. We have found that a risk management approach can help 
define the need and use for biometrics for security. In addition, a 
decision to use biometrics should consider the costs and benefits of 
such a system and its potential effect on convenience and privacy.

Risk Management Is the Foundation of Effective Strategy:

The approach to good security is fundamentally similar regardless of 
the assets being protected. As we have previously reported, these 
principles can be reduced to five basic steps that help to determine 
responses to five essential questions (see figure 2).[Footnote 14]

Figure 2: Five Steps in the Risk Management Process:

[See PDF for image]

Source: GAO.

[End of figure]

What Am I Protecting?

The first step in risk management is to identify assets that must be 
protected and the impact of their potential loss.

Who Are My Adversaries?

The second step is to identify and characterize the threat to these 
assets. The intent and capability of an adversary are the principal 
criteria for establishing the degree of threat to these assets.

How Am I Vulnerable?

The third step involves identifying and characterizing vulnerabilities 
that would allow identified threats to be realized. In other words, 
what weaknesses can allow a security breach?

What Are My Priorities?

In the fourth step, risk must be assessed and priorities determined for 
protecting assets. Risk assessment examines the potential for the loss 
or damage to an asset. Risk levels are established by assessing the 
impact of the loss or damage, threats to the asset, and 

What Can I Do?

The final step is to identify countermeasures to reduce or eliminate 
risks. In doing so, the advantages and benefits of these 
countermeasures must also be weighed against their disadvantages and 

Protection, Detection, and Reaction Are Integral Security Concepts:

Countermeasures identified through the risk management process support 
the three integral concepts of a holistic security program: protection, 
detection, and reaction. Protection provides countermeasures such as 
policies, procedures, and technical controls to defend against attacks 
on the assets being protected. Detection monitors for potential 
breakdowns in protective mechanisms that could result in security 
breaches. Reaction, which requires human involvement, responds to 
detected breaches to thwart attacks before damage can be done. Because 
absolute protection is impossible to achieve, a security program that 
does not incorporate detection and reaction is incomplete.

Biometrics can support the protection component of a security program. 
It is important to realize that deploying them will not automatically 
eliminate all security risks. Technology is not a solution in 
isolation. Effective security also entails having a well-trained staff 
to follow and enforce policies and procedures. Weaknesses in the 
security process or failures by people to operate the technology or 
implement the security process can diminish the effectiveness of 

Accordingly, there is a need for the security process to account for 
limitations in technology. For example, procedures for exception 
processing would also need to be carefully planned. As we described, 
not all people can enroll in a biometrics system. Similarly, false 
matches and false nonmatches will also sometimes occur. Procedures need 
to be developed to handle these situations. Exception processing that 
is not as good as biometric-based primary processing could be exploited 
as a security hole. The effect on the process is directly related to 
the performance of the technology. In our study of biometrics for 
border security, we found that fingerprint recognition appears to be 
the most mature of the biometric technologies. Fingerprint recognition 
has been used the longest and has been used with databases containing 
up to 40 million entries. Iris recognition is a young technology and 
has not been used with large populations. While facial recognition has 
also been used with large databases, its accuracy results in testing 
have lagged behind those of iris and fingerprint recognition.

As with any credentialing or identity management system, it is critical 
to consider the process used to issue the credential. Biometrics can 
help ensure that people can only enroll into a security system once and 
to ensure that a person presenting himself before the security system 
is the same person that enrolled into the system. However, biometrics 
cannot necessarily link a person to his or her true identity. While 
biometrics would make it more difficult for people to establish 
multiple identities, if the one identity a person claimed were not his 
or her true identity, then the person would be linked to the false 
identity in the biometric system. The use of biometrics does not 
relieve the credential-issuing authority of the responsibility of 
ensuring the identity of the person requesting the credential or of 
conducting a security check, commensurate with the level of access 
being granted, to assure itself that the person is entitled to receive 
the credential. The quality of the identifier presented during the 
enrollment process is key to the integrity of a biometrics system.

Even if the biometric is checked against a biometrics-based watch list, 
the effectiveness of such a list is also dependent on nontechnological 
processes. The policies and procedures governing the population of the 
watch list as well as the effectiveness of the law enforcement and 
intelligence communities to identify individuals to place on the watch 
list are critical to the success of the program. People who are not on 
the watch list cannot be flagged as someone who is not eligible to 
receive a credential.

Deciding to Use Biometric Technology:

A decision to use biometrics in a security solution should also 
consider the benefits and costs of the system and the potential effects 
on convenience and privacy.

Weighing Costs and Benefits:

Best practices for information technology investment dictate that prior 
to making any significant project investment, the benefit and cost 
information of the system should be analyzed and assessed in detail. A 
business case should be developed that identifies the organizational 
needs for the project and a clear statement of high-level system goals 
should be developed. The high-level goals should address the system's 
expected outcomes such as the binding of a biometric feature to an 
identity or the identification of undesirable individuals on a watch 
list. Certain performance parameters should also be specified such as 
the time required to verify a person's identity or the maximum 
population that the system must handle.

Once the system parameters are developed, a cost estimate can be 
developed. Not only must the costs of the technology be considered, but 
also the costs of the effects on people and processes. Both initial 
costs and recurring costs need to be estimated. Initial costs need to 
account for the engineering efforts to design, develop, test, and 
implement the system; training of personnel; hardware and software 
costs; network infrastructure improvements; and additional facilities 
required to enroll people into the biometric system. Recurring cost 
elements include program management costs, hardware and software 
maintenance, hardware replacement costs, training of personnel, 
additional personnel to enroll or verify the identities of people in 
the biometric system, and possibly the issuance of token cards for the 
storage of biometrics.

Weighed against these costs are the security benefits that accrue from 
the system. Analyzing this cost-benefit trade-off is crucial when 
choosing specific biometrics-based solutions. The consequences of 
performance issues--for example, accuracy problems, and their effect on 
processes and people--are also important in selecting a biometrics 

Effects on Privacy and Convenience:

The Privacy Act of 1974 limits federal agencies' collection, use, and 
disclosure of personal information, such as fingerprints and 
photographs.[Footnote 15] Accordingly, the Privacy Act generally covers 
federal agency use of personal biometric information. However, the act 
includes exemptions for law enforcement and national security purposes. 
Representatives of civil liberties groups and privacy experts have 
expressed concerns regarding (1) the adequacy of protections for 
security, data sharing, identity theft, and other identified uses of 
biometric data and (2) secondary uses and "function creep." These 
concerns relate to the adequacy of protections under current law for 
large-scale data handling in a biometric system. Besides information 
security, concern was voiced about an absence of clear criteria for 
governing data sharing. The broad exemptions of the Privacy Act, for 
example, provide no guidance on the extent of the appropriate uses law 
enforcement may make of biometric information. Because there is no 
general agreement on the appropriate balance of security and privacy to 
build into a system using biometrics, further policy decisions are 
required. The range of unresolved policy issues suggests that questions 
surrounding the use of biometric technology center as much on 
management policies as on technical issues.

Finally, consideration must be given to the convenience and ease of 
using biometrics and their effect on the ability of the agency to 
complete its mission. For example, some people find biometric 
technologies difficult, if not impossible, to use. Still others resist 
biometrics because they believe them to be intrusive, inherently 
offensive, or just uncomfortable to use. Lack of cooperation or even 
resistance to using biometrics can affect a system's performance and 
widespread adoption.

Furthermore, if the processes to use biometrics are lengthy or 
erroneous, they could negatively affect the ability of the assets being 
protected to operate and fulfill its mission. For example, in 2002, we 
found that there are significant challenges in using biometrics for 
border security. The use of biometric technologies could potentially 
impact the length of the inspection process. Any lengthening in the 
process of obtaining travel documents or entering the United States 
could affect travelers significantly. Delays inconvenience travelers 
and could result in fewer visits to the United States or lost business 
to the nation. Further studies could help determine whether the 
increased security from biometrics could result in fewer visits to the 
United States or lost business to the nation, potentially adversely 
affecting the American economy and, in particular, the border 
communities. These communities depend on trade with Canada and Mexico, 
which totaled $653 billion in 2000.

In conclusion, biometric technologies are available today that can be 
used for aviation security. However, it is important to bear in mind 
that effective security cannot be achieved by relying on technology 
alone. Technology and people must work together as part of an overall 
security process. As we have pointed out, weaknesses in any of these 
areas diminishes the effectiveness of the security process. We have 
found that three key considerations need to be addressed before a 
decision is made to design, develop, and implement biometrics into a 
security system:

Decisions must be made on how the technology will be used.

A detailed cost-benefit analysis must be conducted to determine that 
the benefits gained from a system outweigh the costs.

A trade-off analysis must be conducted between the increased security, 
which the use of biometrics would provide, and the effect on areas such 
as privacy and convenience.

Security concerns need to be balanced with practical cost and 
operational considerations as well as political and economic interests. 
A risk management approach can help federal agencies identify and 
address security concerns. To develop security systems with biometrics, 
the high-level goals of these systems need to be defined, and the 
concept of operations that will embody the people, process, and 
technologies required to achieve these goals needs to be developed. 
With these answers, the proper role of biometric technologies in 
aviation security can be determined. If these details are not resolved, 
the estimated cost and performance of the resulting system will be at 

Mr. Chairman, this concludes my statement. I would be pleased to answer 
any questions that you or members of the subcommittee may have.


For further information, please contact Keith Rhodes at (202)-512-6412 
or Richard Hung at (202)-512-8073.


[1] U.S. General Accounting Office, Technology Assessment: Using 
Biometrics for Border Security, GAO-03-174 (Washington, D.C.: Nov. 15, 

[2] International Biometric Group, "Framework for Evaluating and 
Deploying Biometrics in Air Travel Applications: Surveillance, Trusted 
Travel, Access Control" (Apr. 3, 2002). 

[3] Aviation and Transportation Security Act (Public Law 107-71, Nov. 
19, 2001). 

[4] U.S. General Accounting Office, Security: Breaches at Federal 
Agencies and Airports, GAO/T-OSI-00-10 (Washington, D.C.: May 25, 

[5] Aviation and Transportation Security Act, §106(c) and §136, and 
Maritime Transportation Security Act of 2002 (Public Law 107-295, Nov. 
25, 2002), §102. 

[6] Aviation and Transportation Security Act, §106(d). 

[7] Aviation and Transportation Security Act, §109(a)(3). 

[8] U.S. General Accounting Office, Aviation Security: Registered 
Traveler Program Policy and Implementation Issues, GAO-03-253 
(Washington D.C.: Nov. 22, 2002).

[9] The visa waiver program permits nationals from designated countries 
to apply for admission to the United States for 90 days or less as 
nonimmigrant visitors for business or pleasure without first obtaining 
a U.S. nonimmigrant visa.

[10] We describe several of these uses in Technology Assessment: 
Biometrics for Border Security, GAO-03-174. 

[11] See the Uniting and Strengthening America by Providing Appropriate 
Tools Required to Intercept and Obstruct Terrorism Act of 2001 (USA 
PATRIOT Act) (Public Law 107-56, Oct. 26, 2001), §403(c) and §414, and 
the Enhanced Border Security and Visa Entry Reform Act of 2002 (Public 
Law 107-173, May 14, 2002), §202(a)(4) and §303.

[12] In January 2003, in response to this requirement, NIST submitted 
its technical standards for biometric identifiers and tamper-resistance 
for travel documents as a part of a joint report to the Congress from 
the Attorney General, the Secretary of State, and NIST. NIST 
recommended that 10 fingerprints be used for background identification 
checks and that a dual biometric system using 2 fingerprint images and 
a face image may be needed to meet projected system requirements for 

[13] GAO has conducted reviews of annual expenditure plans of the US-
VISIT program. The review of the fiscal year 2004 expenditure plan can 
be found in U.S. General Accounting Office, Homeland Security: First 
Phase of Visitor and Immigration Status Program Operating, but 
Improvements Needed, GAO-04-586 (Washington, D.C.: May 11, 2004).

[14] U.S. General Accounting Office, National Preparedness: 
Technologies to Secure Federal Buildings, GAO-02-687T (Washington, 
D.C.: Apr. 25, 2002).

[15] 5 U.S.C. §552a.