National Preparedness: Technologies to Secure Federal Buildings
(25-APR-02, GAO-02-687T).
The terrorist attacks of September 11 have heightened concerns
about the physical security of federal buildings and the need to
protect those who work in and visit these facilities. These
concerns have been underscored by reports of long-standing
vulnerabilities, including weak controls over building access.
There are several commercially available security technologies
that can be deployed, ranging from turnstiles, to smart cards, to
biometric systems. Although many of these technologies can
provide highly effective technical controls, the overall security
of a federal building will depend on robust risk management
processes and implementing the three integral concepts of a
holistic security process: protection, detection, and reaction.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-02-687T
ACCNO: A03185
TITLE: National Preparedness: Technologies to Secure Federal
Buildings
DATE: 04/25/2002
SUBJECT: Counterterrorism
Facility security
Federal facilities
Internal controls
Physical security
Risk management
Strategic planning
Terrorism
Federal Buildings Fund
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GAO-02-687T
GAO- 02- 687T
NATIONAL PREPAREDNESS
Technologies to Secure Federal Buildings
Statement of Keith A. Rhodes Chief Technologist
For Release on Delivery Expected at 2: 00 EDT Thursday, April 25, 2002
Testimony Before the Subcommittee on Technology and Procurement Policy,
Committee on Government Reform, House of Representatives
United States General Accounting Office
GAO
Page 1 GAO- 02- 687T
Mr. Chairman and Members of the Subcommittee: Thank you for inviting me to
participate in today?s hearing on security technologies to protect federal
facilities. The terrorist attacks of September 11 on the World Trade Center
and the Pentagon have intensified concerns about the physical security of
our federal buildings and the need to protect those who work in and visit
these facilities. These concerns have been underscored by reports of long-
standing vulnerabilities, including weak controls over building access.
As you requested, today I will discuss commercially available security
technologies that can be deployed to protect these facilities, ranging from
turnstiles, to smart cards, to biometric systems. While many of these
technologies can provide highly effective technical controls, the overall
security of a federal building will hinge on establishing robust risk
management processes and implementing the three integral concepts of a
holistic security process: protection, detection, and reaction.
First I will provide an overview of the technologies that provide
protection, detection, and reaction capabilities against the most prevalent
threats. I will describe the characteristics and capabilities of each of
these technologies and summarize their effectiveness, as well as their
maturity and other performance factors to be considered in implementing
them. While not endorsing any product, I will also identify vendors and
costs. Finally, I will discuss the considerable technical challenges and
user acceptance issues still ahead in their implementation.
In conducting our review, we interviewed officials at federal agencies
responsible for the physical security of their buildings, including the
General Service Administration?s (GSA) Federal Protective Service, the
Defense Protective Service, the U. S. Capitol Police, and GAO?s own Office
of Safety and Security. To understand the availability and effectiveness of
newer security technologies, we also met with officials from GSA?s General
Products Center and technologists from the National Institute of Justice?s
Office of Science and Technology, the Department of Defense?s (DoD)
Biometrics Management Office, and the Biometrics Foundation. We coordinated
with the Security Industry Association and its advisory councils that
represent the different security industries within the scope of our work.
They provided us with valuable information and contacts. We attended the
Biometric Consortium Conference and the International Security Conference
and Exposition, where newer technologies were demonstrated and where we
discussed aspects of the technologies with industry representatives. We also
discussed the results of several of the Federal Aviation Administration?s
biometric prototype initiatives with
Page 2 GAO- 02- 687T
program managers. To familiarize ourselves with available security products,
we also conducted an extensive literature search and obtained and perused
technical studies performed by independent organizations and compared their
results with vendor- provided information. We selected the vendors listed in
the attachments to this testimony based on factors such as market share,
assessment studies, and availability of equipment on the GSA schedule. We
obtained equipment prices from vendors and GSA schedules. Finally, we relied
on previous GAO work on physical building security. We performed our audit
work from February through April 2002 in accordance with generally accepted
government auditing standards.
It is the federal government?s responsibility to assure the physical
protection of its facilities and the safety of employees and visitors of
those federal buildings. GSA, through its Public Building Service (PBS) is
the primary property manager for the federal government, owning or leasing
39 percent of the federal government?s office space. Approximately one
million federal employees, millions of visitors, and thousands of children
and their day- care providers enter these facilities each day. Within PBS,
the Federal Protective Service is responsible for the security of most
GSAmanaged buildings.
Over thirty other executive branch agencies, including DoD and the
departments of State, Veterans Affairs, and Transportation, have some level
of authority to purchase, own, or lease office space or buildings. These
agencies are responsible for the security of their own sites. The U. S.
Secret Service is in charge of the security of the White House and other
executive office buildings. The U. S. Capitol Police secures the Capitol
complex, which includes the Capitol and House and Senate office buildings.
The marshal of the Supreme Court and the Supreme Court Police tend to the
security of the Supreme Court. Marshals from the Department of Justice?s U.
S. Marshals Service ensure the security of other federal courts.
The 1995 domestic terrorist bombing of the Alfred P. Murrah Federal Building
in Oklahoma City, Oklahoma, aroused governmentwide concern about the
physical security of federal buildings. One day after the bombing, then
President Clinton directed Justice to assess the vulnerability of all
federal office buildings in the United States, particularly to acts of
terrorism and other forms of violence. Justice led a working group in
developing a report that established governmentwide minimum Background
Security Issues Have Been Reported at Federal Buildings
Page 3 GAO- 02- 687T
standards for security at all federal facilities. 1 Also in 1995, the
president directed executive departments and agencies to upgrade the
security of their facilities to the extent feasible based on the report?s
recommendations, giving GSA this responsibility for the buildings it
controls. Among the minimum standards for buildings of a higher risk level
specified by the Justice report are security technologies, including closed-
circuit television (CCTV) surveillance cameras, intrusion detection systems
with central monitoring capability, and metal detectors and x- ray machines
to screen people and their belongings at entrances to federal buildings.
In June 1998, we testified on GSA?s efforts to improve federal building
security. 2 We reported that although GSA had made progress implementing
security upgrades in its buildings, it did not have the valid data needed to
assess the extent to which completed upgrades had helped to increase
security or reduce vulnerability to the greatest threats to federal office
buildings. We also expressed concerns about whether all GSA buildings had
been evaluated for security needs. We recommended that GSA correct the data
in its tracking and accounting systems, ensure that all GSA buildings were
evaluated, and develop program goals, measures, and evaluations to better
manage its security enhancement program. In October 1999 we again testified
on GSA?s efforts. 3 During this review, we found that the accuracy of GSA?s
security upgrade tracking system had improved and that almost all of its
buildings had been evaluated for security needs.
However, a review we performed in April and May 2000 exposed a significant
security vulnerability in the access controls at many government buildings.
4 Posing as law enforcement officers, we gained access to 18 federal
facilities, where we reached the offices of 15 cabinet secretaries or agency
heads. Our briefcases were not searched for weapons or explosives.
1 The report, entitled Vulnerability Assessment of Federal Facilities, June
28, 1995, classified federal facilities into 5 security levels ranging from
a level 1, with minimum security needs, to a level 5, with high security
needs. Fifty- two increasingly stringent security standards were
recommended, depending on the level of risk assigned to the building.
2 U. S. General Accounting Office, General Services Administration: Many
Building Security Upgrades Made But Problems Have Hindered Program
Implementation, GAO/ T- GGD- 98- 141 (June 4, 1998).
3 U. S. General Accounting Office, General Services Administration: Status
of Efforts to Improve Management of Building Security Upgrade Program, GAO/
T- GGD/ OSI- 00- 19 (Oct. 7, 1999). 4 U. S. General Accounting Office,
Security: Breaches at Federal Agencies and Airports, GAO/ T- OSI- 0010 (May
25, 2000).
Page 4 GAO- 02- 687T
As mentioned previously, last September?s terrorist attacks against the
World Trade Center and the Pentagon have focused even greater security
concerns about federal buildings. Such concerns have prompted agency
officials to create a more stringent security environment at their
facilities. For example, the Federal Emergency Management Administration
recently informed GSA officials that it was canceling plans to move its
national headquarters and 1,000 workers to the Potomac Center redevelopment
near the waterfront in Washington, D. C. Citing security concerns about the
new building, the agency backed out of a 10- year lease.
Despite a show of increased security, it remains uncertain whether effective
countermeasures have actually been implemented. For example, reporters who
visited a number of government agencies in late October demonstrated that,
without thorough screening, nonemployees could easily gain access to freely
wander the buildings.
Since the 1995 Oklahoma City bombing, the federal government has already
spent more than $1.2 billion on increased security measures for the federal
government?s office space. Following the September 11 th terrorist attacks,
increased resources have been appropriated for this purpose. Specifically,
on September 18, 2001, President Bush signed the Fiscal Year 2001 Emergency
Supplemental Appropriations Act (P. L. 10738), appropriating $40 billion to
respond to the terrorist attacks. The act provides funding to cover the
physical protection of government facilities and employee security. On
September 21, 2001, the president allocated $8.6 million from this
appropriation to GSA?s Federal Buildings Fund to provide increased security
for federal buildings. On October 17, 2001, the president requested that
Congress increase the total to $200.5 million for the Federal Building Fund
for additional security services at federal buildings. The president?s
fiscal year 2003 budget requests that $367 million be made available from
the Federal Building Fund to fund costs associated with implementing
security improvements to federal buildings.
On March 21, 2002, the Bush administration asked Congress for an additional
$27.1 billion in emergency funding for fiscal year 2002 for needs stemming
from the September 11 th terrorist attacks, $5.5 billion of which were for
domestic security. Some of these requested funds will most likely be
invested in technologies to enhance building security. It will be important
to ensure that the technologies that these funds are spent on are effective.
Page 5 GAO- 02- 687T
The approach to good security is fundamentally similar regardless of the
assets being protected. As GAO has previously reported for homeland security
5 and information systems security, 6 applying risk management principles
can provide a sound foundation for effective security whether the assets are
information, operations, people, or federal facilities. These principles,
which have been followed by members of the intelligence and defense
community for many years, can be reduced to five basic steps that help to
determine responses to five essential questions.
Because of the vast differences in types of federal facilities and the
variety of risks associated with each of them, there is obviously no single
approach to security that will work ideally for all buildings. Therefore,
following these basic risk management steps is fundamental to determining
security priorities and implementing appropriate solutions. 7
Figure 1: Five Steps in the Risk Management Process
Source: GAO.
5 U. S. General Accounting Office, Homeland Security: A Risk Management
Approach Can Guide Preparedness Efforts, GAO- 02- 208T (Oct. 31, 2001). 6 U.
S. General Accounting Office, Information Security Management: Learning From
Leading Organizations, GAO/ AIMD- 98- 68, (May 1998). 7 GSA?s building
security upgrade program uses a risk assessment approach whereby threats and
vulnerabilities are identified and corresponding security countermeasures
are identified to either reduce or eliminate each threat and vulnerability.
Risk Management is
the Foundation of
Identify Assets
Identify Threats
Identify Vulnerabilities
Assess Risks & Determine Priorities
Identify Countermeasures
Page 6 GAO- 02- 687T
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. Included among the assets
of federal facilities are the physical safety and peace of mind of the
occupants, the value of the structure itself, and the importance of the
mission of the organization housed in the facility. The symbolic value of
certain landmark federal facilities and monuments must also be considered in
the assessment.
Who Are My Adversaries?
The second step is to identify and characterize the threat to these assets.
Is the threat, for example, that unauthorized individuals can gain access to
the building to commit some crime, or that an authorized yet disgruntled
employee intent on causing harm to fellow employees or the facility can get
in, or, still more menacing, that a terrorist will introduce a chemical/
biological agent or even a nuclear device into the building?
The intent and capability of an adversary are the principal criteria for
establishing the degree of threat to these assets. The terrorist bombing of
the World Trade Center in 1993, the Oklahoma City bombing of the Alfred P.
Murrah Federal Building in 1995, the U. S. embassy bombings in Tanzania and
Kenya in 1998, and last year?s September 11th terrorist attacks on the
Pentagon and the World Trade Center leave no doubt as to the existence of
adversaries intent on causing the maximum harm. And, as these events have
tragically demonstrated, our adversaries certainly have the capability.
Moreover, more recent information gathered by intelligence and law
enforcement agencies have led government officials to believe that both
foreign and domestic terrorist groups continue to pose threats to the
security of our nation?s infrastructure, including our public buildings.
How Am I Vulnerable?
Step three involves identifying and characterizing vulnerabilities that
would allow identified threats to be realized. In other words, what
weaknesses can allow a security breach? For a facility, weaknesses could
include vulnerabilities in the physical layout of the building, its security
systems, and processes. For example, the lack of a standoff distance between
vehicle access and the building itself, which would allow an adversary to
detonate a car or truck bomb within a dangerous distance of the building, is
an example of a vulnerability in the perimeter security of a building. Or,
it might be that an antiquated and labor- intensive access control system in
combination with an inadequate security staff create
Page 7 GAO- 02- 687T
weaknesses in security systems and processes that allow entrance to a
building.
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 of or
damage to an asset. Risk levels are established by assessing the impact of
the loss or damage, threats to the asset, and vulnerabilities. For example,
the risk of loss of human life due to poor access controls on weekends, when
fewer people are working in the building, is lower than on weekdays during
standard working hours.
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 costs.
Many security technologies were developed in a research environment.
However, in a real- world environment, some degree of security must be
traded off against operational and safety considerations. Extreme security
countermeasures cannot be implemented if they could disrupt operations or
adversely affect the safety of the occupants of a building. For example, an
access control system that uses draconian methods to screen employees at
public entrances would be inappropriate except in buildings at the highest
risk level because it would cause maximum inconvenience to large numbers of
building occupants at peak traffic hours. Moreover, an access control system
cannot be so rigid that it impedes the safe exit of a building?s occupants
during emergencies, such as a fire. In all cases, an acceptable balance
between security and these competing factors must be reached, which can only
be decided by the building?s occupants.
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 also incorporate detection and
reaction is incomplete. Protection, Detection,
and Reaction are Integral Security Concepts
Page 8 GAO- 02- 687T
To be effective, all three concepts must be elements of a cycle that work
together continuously. To illustrate, suppose that the protection of a side
door of a federal building is provided by a lock, which is wired to an
intrusion detection sensor, which triggers an alarm to alert a guard to
initiate a reaction. If someone picks the lock, thereby tripping an alarm,
and a guard is monitoring the detection system in real time, she or he will
detect the incident and can react to contain the intrusion and apprehend the
intruder before damage is done. However, if no guard is monitoring the
intrusion detection systems to react to the intrusion, the process breaks
down and the security of the building may be compromised. In other words,
technologies that implement the concepts of protection and detection cannot
alone safeguard a building. An effective human reaction is essential to the
security process.
Myriad security technologies, at various stages of commercial development,
support the security concepts of protection, detection, and reaction. We
have categorized these systems according to the particular concept that they
support. Access control systems provide protection by establishing a
checkpoint at entry points to a building through which only authorized
persons may pass. Detection systems look for dangerous objects and agents on
persons, their belongings, and their vehicles at a building?s entry points.
Intrusion detection systems monitor for security incursions throughout a
building to alert security staff to react to investigate and contain the
intrusion.
The first line of security within a federal building is to channel all
access through entry control points where identity verification devices can
be used for screening. These devices ?authenticate? individuals seeking
entry, i. e., they verify that the individuals are indeed authorized by
electronically examining credentials or proofs of identity.
Identity verification devices use three basic technological approaches to
security based on something you have, something you know, and something you
are. Accordingly, they range from automatic readers of special
identification cards (something you have), to keypad entry devices that
generally require a pin number or password (something you know), to more
sophisticated systems that use biometrics (something you are) to verify the
identity of persons seeking to enter a facility. More secure access control
systems use a combination of several of these approaches at the same time
for additional security.
Technologies used by identity verification devices include the basic bar
code or magnetic strip for card- swipe readers, similar to those used for
credit cards, cards that use radio frequency signals and need only be Myriad
Commercially
Available Security Technologies Support Security Concepts
Access Control Systems
Page 9 GAO- 02- 687T
passed within close proximity to a reader to identify the card holder, and
smart cards that can contain biometric identifiers. Keypad entry devices are
often used in combination with cards and card readers. Newer access control
systems that use biometric technologies to verify the identity of
individuals can significantly increase building security.
The term biometrics covers a wide range of technologies used to verify
identity by measuring and analyzing human characteristics. Identifiable
physiological characteristics include fingerprints, retinas and irises, and
hand and facial geometry. Identifiable behavioral characteristics are speech
and signature. Biometrics theoretically represent a very effective security
approach because biometric characteristics are distinct to each individual
and, unlike identification cards and pin numbers or passwords, they cannot
be easily lost, stolen, or guessed.
Biometric systems first capture samples of an individual?s unique
characteristic that are then averaged to create a digital representation of
the characteristic, known as a template. This template is stored and used to
determine if the characteristic of the individual captured by the identity
verification device at the entry control point matches the stored template
of that individual?s characteristic. Templates can be stored within the
device itself, in a centralized database, or on an access card.
Until recently, in addition to being very expensive, the performance of most
biometric technologies had unreliable accuracy. However, prices have
significantly decreased and, after years of research, the technology has
recently improved considerably. Today biometric devices that read
fingerprints and hand geometry have been operationally deployed and proven
to be affordable and reliable. Nevertheless, other biometric technologies
are not as mature and still tend to falsely reject authorized persons or
falsely accept unauthorized persons. These reliability weaknesses will have
to be overcome before their use can be widespread. User acceptance is also
an issue with biometric technologies in that some individuals find them
difficult, if not impossible, to use. Still other individuals resist
biometrics in general because they perceive them as intrusive and infringing
on their right to privacy.
Once a person is authenticated, access control systems are designed to
electronically allow passage through some barrier. Building access barriers
can range from such conspicuous physical structures as revolving doors to
all but transparent optical turnstiles that generate an alarm when an
unauthorized individual attempts to pass.
Page 10 GAO- 02- 687T
Table 1 provides a high- level description of access control technologies
that can be deployed to protect federal facilities. Attachment I describes
the technologies in greater detail.
Table 1: Access Control Technologies Technology
How the technology works Effectiveness Performance factors User acceptance
Biometrics
Fingerprint scan Patterns of fingertips are captured and compared Reliable
Dirty, dry, worn fingertips
Medium, some resistance based on association with law enforcement
Hand geometry Dimensions of hand and fingers are measured and
compared Fewer unique
characteristics measured Injuries and jewelry Good, but may require minimal
training Retina scan Patterns of blood vessels on
retina are captured and compared
One of most accurate biometrics Hardest to use of biometric
technologies Considered intrusive Iris scan Patterns of iris are captured
and compared One of most accurate biometrics Lighting and movement Medium,
some
resistance based on sensitivity of eye
Facial recognition Facial features are captured and compared
Dependent on lighting, positioning, updating reference template
Environmental factors Good, but some
concern about possible misuse
Speaker recognition
Cadence, pitch, and tone of vocal tract are captured and compared
Better suited for other applications
Environment, inconsistencies, and quality of equipment Good
Signature recognition
Rhythm, acceleration, and pressure flow of signature are captured and
compared
Better suited for other applications Erratic signatures Good
Access cards
Magnetic swipe cards Identification is encoded in
magnetic strip on plastic card Substantially more secure if
used in conjunction with other controls
Subject to demagnetization and wear and tear Good
Page 11 GAO- 02- 687T
Technology How the technology
works Effectiveness Performance factors User acceptance
Proximity cards Identification is encoded in card transmitted by radio
frequency antenna Substantially more secure if
used in conjunction with other controls
More durable than swipe cards Good
Smart cards Identification data are stored in memory chip
Substantially more secure if used in conjunction with other controls
Requires proper care Some concern about security of data stored
on card
Keypad entry systems
Require users to enter passcodes
Substantially more secure if used in conjunction with access card system
Users may forget passcodes; vulnerable to malfunction and vandalism
Good
Access barriers
(turnstiles/ revolving doors)
Used in conjunction with access card systems to bar unauthorized access
Only allows authorized access High traffic flow Good
Detection systems provide a second layer of security. Portal (walkthrough)
metal detectors can be strategically deployed at entry control points to
screen individuals for hidden firearms and other potentially injurious
objects, such as knives and explosive devices, as they clear the access
control system. Unlike more traditional detectors which simply generated an
alarm when a metal target was detected anywhere on an individual?s body,
more technologically advanced portal scanners now come equipped with light
bars to highlight the locations where highest metal concentrations are
detected. More sensitive and ergonomic handheld detector wands are also now
commercially available to perform thorough and rapid follow- up screens.
As individuals proceed through the metal detector, their carried items can
be passed through an x- ray system, which scans the items to obtain an image
of the contents. Low- energy x- ray systems are also currently being tested
to screen individuals for hidden weapons and explosives. However,
performance, privacy, and health issues associated with this technology will
have to be overcome before it can be widely deployed. Though not yet
commercially available, holographic scanning, which can screen for metallic
as well as nonmetallic weapons concealed under clothing, is Detection
Systems
Page 12 GAO- 02- 687T
another new technology currently being tested by the Federal Aviation
Administration.
Explosive trace detectors provide an additional layer of building security.
Security personnel swab the surface of a person?s belongings at entry
control points to check for concealed explosives. The swab is then placed
into the detection device, which tests for the presence of explosive traces.
Portal explosive detection systems and systems that detect large vehicles
carrying bombs are now commercially available, but the technology has not
yet been widely deployed. Finally, more research and development efforts
will be required before technologies for detecting chemical/ biological
agents become more effective and affordable.
Table 2 provides a high- level description of detection technologies that
can be deployed to protect federal facilities. Attachment II describes the
detection technologies in greater detail.
Table 2: Detection Technologies Technology How the technology works
Effectiveness Performance factors User
acceptance
X- ray scanning systems Electromagnetic waves (x- rays) are
used to allow distinct structures to be viewed on a monitor. Due to
differences in material compositions, items are distinguishable.
Persons familiar with the exact construction of a particular x- ray system
could pack a bag to make a threat item difficult to recognize.
Depend on the efficiency of the operator and the amount of clutter in a bag
or on a person.
Some concern about exposure to radiation.
Metal detectors Used to locate concealed metallic weapons on persons. When
the detector senses a questionable item or material, an alarm signal is
produced
Considered a mature technology. Can accurately detect the presence of most
types of firearms and knives. However, they are typically not accurate when
used on objects that contain a large number of different materials.
Can be extremely sensitive to interference from conflicting signals of
nearby objects. Traffic flow depends on welltrained and motivated operators.
Portal detectors require frequent adjustment.
Some concern about exposure to the magnetic field of metal detectors. Issues
of privacy and discrimination have also been raised.
Explosive detection systems Used to detect bulk or trace
explosives concealed in, on, or under vehicles, containers, packages, and
persons.
Technology capable of detecting most military and commercially available
explosives. However, most systems designed to detect only a subset.
Depend on the method used to collect sample and operator efficiency.
Explosive detection units are not intrusive.
Intrusion detection systems alert security staff to react to potential
security incidents. CCTV cameras play an integral part of intrusion
detection systems. Security personnel can use this technology to monitor
activity throughout a building, in particular at entryways, exits,
stairwells, and other areas that are susceptible to intrusion. CCTV
technology is Intrusion Detection
Systems
Page 13 GAO- 02- 687T
mature, practical, and reasonably priced. Moreover, it is highly cost
efficient because one person can monitor several areas on different screens
at the same time from one central location. However, experiments have shown
that relying on security staff to detect incidents by constantly monitoring
scenes from the camera in real time is ineffective. Because watching camera
screens is both boring and mesmerizing, the attention of most individuals
has degenerated to well below acceptable levels after only 20 minutes of
viewing. This is particularly true if staff are watching multiple monitors
simultaneously. A more practical application of CCTV is to interface the
CCTV system with electronic intrusion detection technologies, which alert
security staff to potential incidents requiring monitoring.
Electronic intrusion detectors are designed to identify penetrations into
buildings through vulnerable perimeter barriers such as doors, windows,
roofs, and walls. These systems use highly sensitive sensors that can detect
an unauthorized entry or attempted entry through the phenomena of motion,
vibrations, heat, or sound. Examples are technologies that detect motion
through breaks in a transmitted infrared light beam and heat emitted from a
warm object, such as a human body.
When an intrusion is sensed, a control panel to which the sensors are
connected transmits a signal to a central response area, which is
continually monitored by security personnel. The sensor- detected incident
will alert security personnel of the incident and where it is occurring so
that personnel will know what monitor to pay attention to. By interfacing
these technologies, security personnel can initially assess sensor- detected
security events before determining how to react appropriately.
Alarmtriggered video recorders can also be installed to provide immediate
playback of a detected event for analysis.
Table 3 provides a high- level description of intrusion detection
technologies that can be deployed to secure federal facilities. Attachment
III describes the technologies in greater detail.
Page 14 GAO- 02- 687T
Table 3: Intrusion Detection Systems Technology How the technology works
Effectiveness Performance factors User
acceptance
CCTV A visual surveillance technology for monitoring a variety of
environments and activities. Typically involves a dedicated communications
link between cameras and monitors.
The clarity of the pictures and feed can be excellent. Cameras vary in size,
light sensitivity, resolution, type, and power.
Often not effective as an active surveillance tool because of security
staff?s inattention.
Concern about misuse to track people, racially discriminate, and engage in
voyerism.
Intrusion sensors (line sensors, video motion detectors, balanced magnetic
switches, and sonic and vibration sensors)
Detect penetrations into secure areas through walls, roofs, doors, and
windows. Detection is usually reported by an intrusion sensor and announced
by an alarm, which must be followed by a human assessment to determine
proper response.
Reliable. Susceptible to nuisance alarms which can be generated by animals,
blowing debris, lightning, water, and nearby traffic.
Any disturbance in the electrical power will affect performance.
Users cannot freely open and close windows and doors that have been equipped
with sensors.
Although the newer technologies can contribute significantly to enhancing
building security, it is important to realize that deploying them will not
automatically eliminate all risks. Effective security also entails having a
well- trained staff to follow and enforce policies and procedures. Moreover,
the technical capabilities of security systems must not be overestimated.
Finally, a broad framework of supporting functions must be in place at the
federal, state, and local levels.
Effective security requires technology and people to work together to
implement policies, processes, and procedures that serve as countermeasures
to identified risks. To illustrate this point, let us examine the following
scenario: an organization has policies in place to mitigate the risk of an
outsider committing a harmful act against its employees. One policy states
that entry to the building is restricted to authorized personnel and another
that no weapons may be brought into the building. An access control system
implements the first policy by requiring that people wishing to enter
present a smart card with a biometric that matches the stored biometric of
the authorized person. A detection system implements the second policy by
requiring people to pass through a metal detection portal and their
belongings to be scanned by an x- ray machine. These procedures ensure
compliance with the policies. However, to be effective, security personnel
must enforce the policies by following the prescribed procedures. If
security personnel allow exceptions to these procedures, they are failing to
enforce compliance with the policies. Just as damaging is the lack of
effective security processes. For example, if there are no processes in
place to handle the entry of employees who have forgotten Technology is Not
a
Panacea Technology Cannot Compensate for Human Failure or Ineffective
Security Processes
Page 15 GAO- 02- 687T
their identity access cards, a vulnerability may be created that could be
exploited by adversaries.
Breaches in security resulting from human error are more likely to occur if
personnel do not understand the risks and the policies that are put in place
to mitigate them. Training is essential to successfully implementing
policies by ensuring that personnel exercise good judgment in following
security procedures. In addition, having the best available security
technology cannot ensure protection if people have not been trained in how
to use it properly. Training is particularly essential if the technology
requires personnel to master certain knowledge and skills to operate it. For
example, x- ray inspection systems rely heavily on the operator to detect
concealed objects in the generated x- ray images. If security personnel have
not received adequate training in understanding how the technology works and
detecting threat images, such as a knife, the security system will be much
less effective.
It is also important to determine how effective technologies really are. Are
they actually as accurate as vendors state? In overestimating their
capabilities, security officials risk falling into a false sense of security
and relaxing their vigilance.
During our review, we found instances in which the performance estimates
vendors provided for some of their biometric technologies were far more
impressive than those obtained through independent testing. As always, it is
important to keep in mind the adage of ?buyer beware? when making
procurement decisions. There are publicly available resources that provide
assessment guidance regarding security products. For example, the National
Institute of Justice has evaluated a number of security products over the
past few years and can serve as a valuable resource to federal agencies for
making purchasing decisions. 8
Also bear in mind that lesser technological solutions sometimes may be more
effective and less costly than more advanced technologies. Dogs, for
example, are an effective and time- proven tool for detecting concealed
explosives. The dogs currently used by DoD, for example, can detect nine
different types of explosive materials. And since dogs have the advantage of
being mobile and able to follow a scent to its source, they have significant
advantages over mechanical explosive detection systems in any application
that involves a search.
8 See http:// www. ojp. usdoj. gov/ nij/ about_ sci. htm. The Capabilities
of
Security Technologies Can Be Overestimated
Page 16 GAO- 02- 687T
The use of technologies as countermeasures is identified in the final step
of the risk management process. As such, they are only capable of defending
against recognized threats. If unrecognized threats are not factored into
the risk management process, these risks will not be mitigated and the
technologies that have been implemented may be ineffectual in preparing for
them.
Security managers of federal buildings rely on federal, state, and local
government entities to prevent, detect, and respond to acts of terrorism
against their facilities. Federal security managers typically are not aware
of potential threats posed by foreign and domestic terrorist groups. As
such, they depend on intelligence and law enforcement agencies such as the
Central Intelligence Agency, the Defense Intelligence Agency, and the State
Department?s Bureau of Intelligence and Research to gather information about
and assess such threats against their facility.
Security managers of federal buildings also do not have access to the range
of emergency resources required to respond to terrorist attacks. They rely
on state and local governments to provide fire- fighting, medical personnel,
and other emergency services. They also rely on the police and the judicial
systems to enforce and prosecute violators of the laws and regulations
governing the protection of federal buildings.
Despite significant advances in performance and capability, the newer
security technologies still face considerable technical challenges and user
acceptance issues before they can be effectively integrated and widely
deployed in federal facilities.
First, because there are no industrywide common standards for data exchange
and application programming interfaces 9 for technologies that provide
physical security, most of the equipment used by the technologies in our
review is not interoperable. For example, deploying an access control system
that uses a smart card containing a fingerprint biometric would require at
least three pieces of equipment: the card reader device, the fingerprint
scan device, and the hardware device used to house and operate the biometric
software. If these devices are made by different manufacturers, they cannot
function as an integrated environment without software to connect the
disparate components. Not only does developing the initial customized
software represent substantial expenditures, but
9 The interface between the application software and the application
platform (i. e., operating system), across which all services are provided.
The Involvement of
Multiple Government Entities is Required to Secure Federal Facilities
Substantial Challenges Remain
The Lack of Standards Impedes System Integration
Page 17 GAO- 02- 687T
new software will have to be developed whenever old equipment is replaced by
equipment from a different manufacturer. Moreover, standardizing on one
manufacturer?s equipment is not the most advantageous option since doing so
leaves no range of equipment from which to choose and requires replacing all
existing hardware not made by that manufacturer. Although efforts are
underway to address the lack of standards, it will be some time before this
problem is resolved.
Second, Americans expect and cherish the value and freedom of privacy.
Recent concern within Congress and public interest groups alike about the
intended use of CCTV by D. C. law enforcement agencies has highlighted
issues regarding the consequences of the applications of newer security
technologies on privacy. 10 In general, apprehensions are based on a fear of
misuse, i. e., that these security technologies will be used for purposes
other than for which they were intended. For example, there is a fear that
the government may use the newer surveillance technologies to track people.
In addition, employees fear that management will be tempted to monitor their
performance. Also at issue is whether people will be arbitrarily monitored
based on their race or ethnic origin or whether operators may be tempted to
indulge in video voyeurism by, for example, especially focusing on young,
attractive females.
Another concern is that biometric technologies may reveal confidential
medical information. Because diseases such as AIDS, diabetes, and high blood
pressure cause changes to the retina, some people fear that retinal scans
could compromise the privacy of this information.
Civil liberties advocates also find the newer detection system technologies
too intrusive. The tremendous potential for embarrassment was recently
pointed out by newspapers reporting on low- dose x- ray systems installed at
Orlando International Airport that essentially perform ?virtual strip
searches.? These systems, now in a test phase, can see a person?s body
through clothing. Newspapers published pictures revealing images of a
person?s body- every inch of it- graphically captured by the scanner.
Third, several of the security technologies we reviewed have the
disadvantage of being both complex and inconvenient to use, requiring
considerable user cooperation. Most biometric technologies, in particular,
have some negative features. Retina scanning, for example, feels
10 The House Committee on Government Reform, Subcommittee on the District of
Columbia held a hearing on the expanding use of electronic surveillance in
the District of Columbia on March 22, 2002. During the hearing, the
chairwoman and ranking minority member of the subcommittee emphasized the
need for policies, procedures, and guidance to govern the use of CCTV
technology because of the potential infringement on the public?s privacy
rights. The Use of Several
Security Technologies Continues to Generate Concerns about their Potential
Violation of Expectations of Privacy
Not All Security Technologies Are User Friendly
Page 18 GAO- 02- 687T
physically intrusive to some users because it requires close proximity with
the retinal reading device. Moreover, fingerprinting feels socially
intrusive to some users because of its association with the processing of
criminals.
There is also an assortment of health concerns among a segment of the
population regarding certain security technologies. There is evidence that
pacemakers and hearing aids can be adversely affected by some detection
technologies. However, no evidence has been produced to substantiate fears
of radiation exposure from x- ray systems and apprehensions that certain
detection systems could cause depression or even brain tumors. Certain
groups of individuals resist using biometric devices because of hygiene
issues.
In conclusion, our review has identified myriad commercially available
technologies that implement the three essential concepts of effective
security: protection, detection, and reaction. Many of these technologies
are mature and have already been deployed in various federal facilities,
where their capabilities and effectiveness have been demonstrated. Other
newer technologies appear to offer great potential in helping federal
agencies to ensure the security of their facilities. These technologies
could be adopted in the near future. Other technologies are still in a
nascent stage of development, but are maturing and appear promising. Many
biometric technologies still face barriers in intrusiveness and complexity
that must be addressed before they can be most effectively deployed and
widely accepted by users. However, they offer greater security, and the
challenges to their implementation may not be formidable.
However, of foremost importance is to continue to bear in mind that
effective security can never be achieved by relying on technology alone.
People will always play a fundamental role in all phases: from planning to
implementation and to enforcement. Accordingly, technology and people must
work together as part of an overall security process, beginning with a risk
management approach and incorporating, implementing, and reinforcing those
three essential concepts.
Mr. Chairman and members of the subcommittee, this concludes my statement. I
would be pleased to answer any questions you or the members of the
subcommittee may have.
For further information, please contact me at (202) 512- 6412 or via e- mail
at rhodesk@ gao. gov. Individuals making key contributions to this testimony
included Sophia Harrison, Ashfaq Huda, Richard Hung, Elizabeth Johnston, and
Tracy Pierson. Contacts and
Acknowledgment
Page 19 GAO- 02- 687T
Attachment I: Access Control Technologies The first line of security within
a federal building is to channel all access through entry control points
where identity verification devices can be used for screening. These devices
?authenticate? individuals seeking entry, i. e., they verify that the
individuals are indeed authorized to be there by electronically examining
credentials or proofs of identity.
Identity verification devices use three basic technological approaches to
security based on something you have, something you know, and something you
are. Accordingly, they range from automatic readers of special
identification cards (something you have), to keypad entry devices that
generally require a pin number or password (something you know), to more
sophisticated systems that use biometrics (something you are) to verify the
identity of persons seeking to enter a facility. More secure access control
systems use a combination of several of these approaches at the same time
for additional security.
The term ?biometrics? covers a wide range of technologies used to measure
and analyze human characteristics to verify a person?s identity.
Identifiable physiological characteristics include fingerprints, eye retinas
and irises, and hand and facial geometry. Identifiable behavioral
characteristics are speech and signature. Biometrics represents a
theoretically very effective security approach because these characteristics
are distinct to each individual and, unlike identification cards and pin
numbers or passwords, they cannot be easily lost, stolen, or guessed.
Biometric Access Controls
Page 20 GAO- 02- 687T
Figure 2: Biometric Identification Verification Process
Source: GAO.
Although biometric technologies measure different characteristics, all
biometric access control technologies involve a similar process that
includes the following components:
Enrollment: multiple samples of an individual?s biometric are captured (as
an image or a recording) via an acquisition device (e. g., a scanner or a
camera).
Reference template: the captured samples are averaged and processed to
generate a unique digital representation of the characteristic, which is
stored for future comparisons. Templates are essentially binary number
sequences. The size of the template depends on the technology, but generally
ranges from 10 bytes to 20,000 bytes. It is impossible to recreate the
sample, such as a fingerprint, from the template. Templates can be stored
centrally on a computer database, within the device itself, or on a smart
card.
Verification: a sample of the biometric of the person seeking access to a
building is captured at the entry control point, processed into a trial
template, and compared with the stored reference template to determine if
00 11 010 1 Enrollment
Verification Multipl e
Samples Sampl e
Pr ocessed St ored
Compared Pr ocessed 00 11 010 1 Reference
Templ at e Tri al Templ at e
Mat ch No Mat ch
Page 21 GAO- 02- 687T
they match. 11 Because the reference template is generated from multiple
samples at enrollment, the match is never perfect. Therefore, systems are
configured to verify the identity of users if the match exceeds an
acceptable threshold.
The effectiveness of biometric systems is characterized by two error
statistics: false rejection rates (FRRs) and false acceptance rates (FARs).
For each FRR there is a corresponding FAR. A false reject occurs when a
system rejects a valid identity; a false accept occurs when a system
incorrectly accepts an identity. If biometric systems were perfect, both
error rates would be zero. However, all biometric technologies suffer FRRs
and FARs that vary according to the individual technology and its stage of
development.
Because biometric access control systems are not capable of verifying
identities with 100 percent accuracy, trade- offs must be considered during
the final step of the risk management process when deciding on the
appropriate level of security to establish. These trade- offs have to
balance acceptable risk levels with the disadvantages of user inconvenience.
For example, perfect security would require denying access to everyone.
Conversely, granting access to everyone would result in denying access to no
one. Obviously neither of these extremes is reasonable, and access control
systems must operate somewhere between the two. How much risk one is willing
to accommodate is the overriding factor in adjusting the threshold, which
translates into determining the acceptable FAR. The tighter the security
required, the lower the tolerable FAR.
Vendors of biometric systems are currently claiming that false accepts occur
once out of every 100,000 attempted entries and that the FRR is about 2 to 3
percent. However, because system thresholds are adjusted to accommodate
different FARs, it is often difficult to measure and compare their
effectiveness. Vendors also describe the accuracy of their systems in terms
of an equal error rate, also referred to as the crossover accuracy rate, or
the point where the FAR equals the FRR.
11 Unlike other access control systems, some biometric systems can also
identify an authorized user without the user having to present any other
identifier, such as an identity card or a pin number or password, by looking
through an entire database of authorized users to attempt to find a match.
Whereas verification systems attempt to perform one- to -one matches,
identification systems attempt to perform one- to- many matches. Systems
operating in this mode naturally take longer; the bigger the database, the
slower the search. They are also less accurate.
Page 22 GAO- 02- 687T
Figure 3: General Relationship between FAR and FRR
Source: GAO. As shown, selecting a lower FAR increases the FRR- the chance
that an authorized person will be denied access to a facility. Perfect
security would require denying access to everyone. In this extreme case, the
FAR would be ?0? and the FRR ?1.? Conversely, granting access to everyone
would result in a FRR of ?0? and a FAR of ?1.?
0 0.25 0.5 0.75 1.0 False Rejection Rate (FRR)
False Acceptance Rate (FAR) 0 0.25 0.5 0.75 1.0
Equal Error Rate (ERR) or Crossover Error Rate (CER)
Attachment I- Access Control Technologies: Biometrics
Page 23 GAO- 02- 687T
Fingerprint scan technology (also known as fingerprint recognition) uses the
impressions made by the unique, minute, ridge formations or patterns found
on the fingertips. Although fingerprint patterns may be similar, no two
fingerprints have ever been found to contain identical individual ridge
characteristics. These characteristics develop on normal hands and feet some
months before birth and remain constant, except for accidental damage or
until decomposition after death.
The image of the fingerprint is captured either optically or electrically. 1
A template is then created from the image. There are two primary methods for
creating templates. Most fingerprint scan technologies base the template on
minutiae, or the breaks in the ridges of the finger (such as ridge endings
or points where a single ridge divides into two). The second method is based
on pattern matching of the ridge patterns. In neither method is the template
a full fingerprint image, and a real fingerprint cannot be recovered from
the digitized template. The generated template ranges from 250 bytes for
minutiae- based templates to about 1000 bytes for ridge- pattern- based
templates.
Vendors commonly claim an FRR of 0.01 percent. Despite a low FAR,
independent testing has shown that some scanning devices can have a FRR of
nearly 50 percent.
1 A third method, using ultrasound technology, is not yet widely used.
Attachment I- Access Control Technologies:
Biometrics Fingerprint Scan
How the technology works Effectiveness
Attachment I- Access Control Technologies: Biometrics
Page 24 GAO- 02- 687T
In a small percentage of the population, fingerprints cannot be captured
because a person?s fingerprints are dirty or have become dry or worn due to
age, extensive manual labor, or exposure to corrosive chemicals. In
addition, the optical method of fingerprint scanning can be prone to errors
if there is a buildup of dirt, grime, or oil on the surface of the device
where the image is captured.
Because fingerprints have historically been used by law enforcement agencies
to identify criminals, there is some user resistance to this technology.
Also, people may have hygienic issues with having to touch the plate of the
scanner that has previously been touched by many people.
According to a 2001 report published by Gartner Group, Inc., the leading
vendors are American Biometric Company, Digital Persona Inc., Identix Inc.,
and Bioscrypt, Inc. (formerly Mytec Technologies Inc.).
The GSA schedule lists fingerprint readers designed for physical access
control at prices ranging from about $1,000 to about $3,000 per unit.
Software licenses for the fingerprint technology are listed for about $4.00
per user enrolled. Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 25 GAO- 02- 687T
Hand (or finger) geometry 1 is based on the premise that each individual?s
hands, although changing over time, remain characteristically the same. The
technology collects over 90 automated measurements of many dimensions of the
hand and fingers, using such metrics as the height of the fingers, distance
between joints, and shape of the knuckles. The user?s hand is placed on the
sensor?s surface, typically guided into proper position by pegs between the
fingers. Only the spatial geometry is examined; prints of the palm or
fingers are not taken. About a 10- to 20- byte template is created from hand
geometry.
Independent testing of the leading hand geometry readers (manufactured by
Recognition Systems, Inc.) at Sandia National Laboratories in 1991 produced
a FAR of less than 0.1 percent and an FRR of less than 0.1 percent.
Hand geometry is not considered as robust as other biometric access control
technologies because of similarities between individual hand templates. Not
as much distinguishing information can be found in a hand compared to an
iris or a fingerprint.
1 Hand geometry uses the entire hand; finger geometry typically uses two or
three fingers. However, the technology is the same for both and will be
referred to as ?hand geometry? in this document. Attachment I- Access
Control Technologies:
Biometrics Hand Geometry
How the technology works Effectiveness
Attachment I- Access Control Technologies: Biometrics
Page 26 GAO- 02- 687T
Hand geometry is a well- developed technology, which disregards fingernails
and surface details such as fingerprints, lines, scars, and dirt. However,
hand injuries and jewelry can impede accurate readings and/ or comparisons.
Whether used for verification or identification purposes, the stored image
templates must be kept updated as appearances are naturally altered by age.
Hand geometry is considered to be easy to use, although a minimal amount of
training is required for users to align their hands in the reader.
The hand geometry market is dominated by Recognition Systems, Inc. The
finger geometry market is led by BioMet Partners.
Hand geometry reader devices generally cost between $2,000 to $4,000.
Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 27 GAO- 02- 687T Retina scan technology is based on the patterns of
blood vessels on the retina, a thin nerve about 1/ 50th of an inch thick
located on the back of the
eye. These patterns are unique from person to person. No two retinas are
alike, not even in identical twins. Retinal patterns remain constant
throughout a person?s lifetime except in cases of certain diseases.
Retina scan devices project a low- intensity infrared light through the
pupil and onto the retina. The patterns of the retina?s blood vessels are
measured at over 400 points to generate a 96- byte template.
Retinal scanning, along with iris scanning technology, is the most accurate
and reliable of the biometric technologies. It is virtually impossible to
replicate the image produced by a human retina. It has been used as a
mainstay technology for controlling access to highly secure government
facilities.
Depending upon system threshold settings, FRRs can be as low as 0.1 percent
and FARs as low as 0.0001 percent (1 in 1,000,000).
Retina scan biometrics are the hardest to use. The older technology requires
users to repeatedly focus on a rotating green light through a small opening
in the scanning device, located within 1/ 2 inch of his or her eye, and to
hold very still for 10 to 12 seconds at a time. However, a newly developed
technology is capable of capturing a retinal image at distances as great as
a meter from the user?s eye in 1.5 seconds. Also whereas glasses, contact
lenses, and existing medical conditions, such as cataracts, Attachment I-
Access Control Technologies:
Biometrics Retina Scan
How the technology works Effectiveness Performance factors
Attachment I- Access Control Technologies: Biometrics
Page 28 GAO- 02- 687T interfere with the older scanning technology, the
newer technology is more accommodating.
Though stable over time, the retina can be affected by diseases such as
glaucoma, diabetes, high blood pressure, and AIDS.
Even though the technology itself is completely safe, users tend to be
resistant to its use because the eye is a very delicate area. Users perceive
the technology as intrusive because it requires the use of infrared rays to
obtain an accurate reading. Additionally, some users are very hesitant to
use the device because the older technology requires close proximity or even
contact with the scanner. The newer technology is less intrusive. Some
people fear that retinal scans could compromise the privacy of confidential
medical information because certain patterns of blood vessels in the retina
can be associated with certain diseases.
Until recently EyeDentify Inc. was the sole vendor of retina systems.
Retinal Technologies, Inc. has lately entered the market with a new retinal
scan technology.
Retina scan devices cost approximately $2,000 to $2,500, placing them toward
the high end of the physical security spectrum. User acceptance
Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 29 GAO- 02- 687T
Source: LG Electronics.
Iris scan technology is based on the unique visible characteristics of the
eye?s iris, the colored ring that surrounds the pupil. The iris of each eye
is different; even identical twins have different iris patterns. The iris
remains constant over a person?s lifetime. Even medical procedures such as
refractive surgery, cataract surgery, and cornea transplants do not change
the iris?s characteristics.
Built from elastic connective tissue, the iris is a very rich source of
biometric data. Complex patterns include striations, rings, furrows, a
corona, and freckles. Whereas traditional biometrics have only 13 to 60
unique characteristics, an iris has about 266.
A high- resolution black- and- white digital image of the iris is taken to
collect data. The system then defines the boundaries of the iris,
establishes a coordinate system over the iris, and defines the zones for
analysis within the coordinate system. The visible characteristics within
the zones are then converted into a 512- byte template.
Iris scanning is considered one of the more secure identity verification
methods available. Because of the massive quantity of biometric data that
can be derived from the iris, the template that is created is unique. In
fact, the odds of two different irises returning identical templates is 1 in
10 52 .
The technology cannot be foiled by wearing contact lenses or presenting an
artificial eye to the reading device because algorithms check for the
presence of a pattern on the sphere of the eye instead of on an internal
plane and use measurements at different wavelengths to detect if the eye is
living. Attachment I- Access Control Technologies:
Biometrics Iris Scan
How the technology works Effectiveness
Attachment I- Access Control Technologies: Biometrics
Page 30 GAO- 02- 687T
The Army Research Laboratory recently tested an identification system using
iris scan technology from Iridian Technologies. The results indicated an FRR
of 6 percent and a FAR of 1 to 2 percent. Few other independent tests of the
iris scan technology have been published.
Both the enrollment and verification steps are easy. Contact lenses, even
colored ones, normally do not interfere with the process. Wearers of
exceptionally strong glasses could have problems, but these could always be
removed. Iris recognition can even be used to verify the identity of blind
people as long as one of their sightless eyes has an iris. Any unusual
lighting situations may affect the ability of the camera to capture the
subject. Also, glare and reflections, along with user settling and
distraction, can cause interferences.
Unlike other biometric identification verification technologies such as
fingerprinting or hand geometry, iris scan technology requires no body
contact. Although some users resist technologies that scan the eye, the iris
scan is more user friendly than the retinal scan because no light source is
shown into the subject?s eye and close proximity to the scanner is not
required. Users can simply glance into a standard video camera from a
distance of about 10 inches and have their identity verified in
approximately 2 seconds.
According to a 2001 report published by Gartner Group, Inc., Iridian
Technologies is the sole owner and developer of iris recognition technology.
Vendors licensing iris technology include: EyeTicket Corporation, LG
Electronics, and Panasonic.
Iris recognition was traditionally among the most expensive biometric
technologies costing tens of thousands of dollars. The significant drop in
the price of computer hardware and cameras has brought the price down.
However, an iris recognition system still costs approximately between $4,000
and $5,000. Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 31 GAO- 02- 687T
Facial recognition is a biometric technology that identifies people based on
their facial features. Systems using this technology capture facial images
from video cameras and generate templates for comparing a live facial scan
of an individual to a stored template.
These comparisons are used in either verifying or identifying an individual.
Verification systems (also known as one- to- one matching systems) compare a
person?s facial scan to a stored template for that person, and can be used
for access control. In an identification system (or a one- tomany matching
system), a person?s facial scan is compared to a database of multiple stored
templates. This makes an identification system more suited for use in
surveillance in conjunction with CCTV to, for example, spot suspected
terrorists whose facial characteristics have already been captured and a
template generated and stored in a database.
There are two primary types of facial recognition technology used to create
templates:
1. Local feature analysis- Dozens of images from regions of the face are
captured, resulting in feature- specific fields such as eyes, nose, mouth,
and cheeks. These feature- specific fields are used as blocks of a
topographical grid. The types of blocks and their positions are used to
identify the face. Small shifts in a feature are anticipated to cause a
related shift in an adjacent feature. Attachment I- Access Control
Technologies:
Biometrics Facial Recognition
How the technology works
Attachment I- Access Control Technologies: Biometrics
Page 32 GAO- 02- 687T
2. Eigenface method- Unlike local feature analysis, the eigenface method
always looks at the face as a whole. A collection of face images is used to
generate a set of two- dimensional, grayscale images to produce the
biometric template. When a live image of a person?s face is introduced, the
system represents the image as a combination of templates. This combination
is compared to a set of stored templates in the system?s database, and the
degree of variance determines whether or not a face is recognized.
Modifications of the algorithms used in local feature analysis and eigenface
methods can lead to variances which incorporate the following:
Neural network mapping- Comparisons of a live facial image to a stored
template are based on unique global features rather than individual
features. Upon a false match, the comparison algorithm modifies the weight
given to certain features (such as shadows).
Automatic face processing- Facial images are captured and analyzed from
the distances and distance ratios between features (such as between the
eyes).
Testing of an identification system was performed using the Face Recognition
Technology (FERET) database. 1 According to results of recent testing, 2 the
typical recognition performance of frontal images taken on the same day is
95- percent accuracy. For images taken with different cameras and lighting,
typical performance drops to 80 percent accuracy. For images taken 1 year
later, the typical accuracy is approximately 50 percent.
The Army Research Laboratory recently tested an identification system using
facial recognition technology. Despite vendor claims of 75 percent correct
identification, the testing showed that only 51 percent were correctly
identified. Further, the correct identification was in the system?s top 10
possible matches only 81 percent of the time instead of the vendorclaimed
99.3 percent.
1 The FERET program is sponsored by the U. S. Department of Defense
Counterdrug Technology Development Program. 2 In September 1996, the FERET
program administered the third in a series of FERET facerecognition tests.
These tests used a single gallery containing 1, 196 frontal images gathered
between 1993 and 1996. Effectiveness
Attachment I- Access Control Technologies: Biometrics
Page 33 GAO- 02- 687T
Facial recognition technology cannot effectively distinguish between
identical twins.
The effectiveness of facial recognition technology is heavily influenced by
environmental factors, especially lighting conditions. Variations in camera
performance, facial position, facial expression, and facial features (e. g.,
hairstyle, eyeglasses, and beards) further affect performance. As a result,
current facial recognition technology is most effective when used in
consistent lighting conditions with cooperative subjects in a mug- shot-
like position (where hats and sunglasses are removed and individuals look
directly at the camera one at a time).
Whether used for verification or identification purposes, the stored image
templates must be kept updated since appearances are naturally altered by
age.
When used in a verification system for access control, facial recognition is
typically considered by users to be less intrusive than other biometric
technologies, such as iris scanners and fingerprint readers. However, when
used in an identification system, there are concerns that this technology
can be used to facilitate the tracking of individuals without their consent.
According to a 2001 report published by Gartner Group, Inc. the leading
vendors are eTrue Inc., Viisage Technology Inc., and Visionics.
For an installation with up to 30,000 persons, a facial- recognition server
costs about $15,000. Depending on the number of entry points using
facialrecognition technology, software licenses range from about $650 to
$4,500. Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 34 GAO- 02- 687T
Speaker verification works by creating a voice template based on the unique
characteristics of an individual?s vocal tract, which results in differences
in the cadence, pitch, and tone of an individual?s voice.
During enrollment, samples of a person?s speech are captured by having the
person speak some predetermined information into a microphone or a telephone
handset (e. g., name, birth month, birth city, favorite color, or mother?s
first name). A template is then generated from these ?passphrases? and
stored for future comparison. When attempting to gain access, the person is
asked by the system to speak one or more of the randomly selected enrolled
passphrases for comparison.
Some speaker recognition systems do not rely on a fixed set of enrolled
passphrases to verify a speaker?s identity. Instead these systems are
trained to recognize similarities in the voice patterns of individuals when
they speak unfamiliar phrases with the voice patterns they are familiar with
based on previously enrolled phrases. This is similar to the way in which
the human brain instinctively attempts to match an unfamiliar word that it
hears with one that it already knows.
The typical biometric voice template is between 10,000 and 20, 000 bytes.
Although speaker verification can be used for physical access control, it is
more often used in environments in which voice is the only available
biometric identifier, such as telephony and call centers.
Equal error rates for systems that use a fixed set of enrolled passphrases
range between 1 and 6 percent, depending on the number of words in the
passphrase.
Systems that do not rely on a fixed set of enrolled paraphrases are not as
accurate. The more unfamiliar phrases the system is required to compare, the
more likely that a false accept will occur.
Performance increases with higher- quality input devices. Some speaker
verification systems provide safeguards against the use of a recorded voice
to spoof the system. For these systems, the electronic properties of a
recording device, particularly the playback speaker, will Attachment I-
Access Control Technologies:
Biometrics Speaker Verification How the technology works
Effectiveness
Attachment I- Access Control Technologies: Biometrics
Page 35 GAO- 02- 687T
change the acoustics to such a degree that the recorded voice sample will
not match a stored voiceprint of a ?live? voice.
The enrollment procedure takes less than 30 seconds. The user must be
positioned near the acquisition device. Users must speak clearly and in the
same manner during enrollment and verification. The typical verification
time is 4 to 6 seconds.
Changes in the voice due to factors such as a severe cold might make
verifying the voice more difficult. Environmental factors such as background
noise also affect system performance. Other factors that can affect
performance include different enrollment and verification capture devices,
different enrollment and verification environments, speaking softly, poor
placement of the capture device, and the quality of the capture device.
Speaker verification systems have a high user acceptance rate because they
are perceived as less intrusive than other biometric devices and they are
also the easiest to use.
According to a 2001 report published by Gartner Group, Inc., the leading
vendors are Buytel, T- NETIX Inc., Veritel Corporation, and VeriVoice Inc.
The list price for a 16- door system is $21, 000. Overall speaker
verification can cost between $70 and $250 per user. Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Biometrics
Page 36 GAO- 02- 687T
Signature recognition authenticates the identity of individuals by measuring
their 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, the user signs his or her signature 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 system compares not merely what the signature looks
like, but also how it is signed. The technology can also track each person?s
natural signature fluctuations over time.
The signature dynamics information is encrypted and compressed and can then
be stored in a database system, smart card, or token device. The stored
template size is 1,500 bytes.
The use of signature recognition for access control seems fairly limited. A
proficient ?forger? is quite capable of selectively provoking false accept
identifications for individual users.
The typical verification time is from 4 to 6 seconds. Several performance
factors may impede signature verification. These include a user signing too
quickly, a user having an erratic signature, a signature that is
particularly susceptible to emotional and health changes, and using
different signing positions. Attachment I- Access Control Technologies:
Biometrics Signature Recognition
How the technology works Effectiveness Performance factors
Attachment I- Access Control Technologies: Biometrics
Page 37 GAO- 02- 687T
Enrollment usually requires several consistent captures. The system is easy
to use, non- intrusive, and requires no staff or customer training, nor any
alteration in signing modes or habits. Because dynamic signature
verification closely resembles the traditional signature process, it has
minimal user acceptance issues. The graphics tablet can be inconvenient as
an input device. While the principal criticism is that the person does not
see what he is writing, the rather soft base on which the person signs also
takes some getting used to.
According to a 2001 report published by Gartner Group, Inc., the leading
vendors are Communication Intelligence Corporation and Cyber- SIGN Inc.
Additional vendors include Hesy, WonderNet, and ScanSoft.
A signature recognition tablet costs about $375. User acceptance
Vendors Unit price range
Attachment I- Access Control Technologies: Access Cards
Page 38 GAO- 02- 687T
Systems based on magnetic swipe cards allow users to access buildings by
inserting or swiping a uniquely coded access card through a reader. Magnetic
swipe cards have a narrow strip (magstripe) of magnetic material fused to
the back of a plastic card, which is very similar to a piece of cassette
tape. The size of the card and the position of the magnetic strip are set by
the International Organization for Standardization (ISO) standards. A
typical bank or credit card is an example of a magnetic swipe card.
The principle of an access control system that uses magnetic swipe
technology is that a unique number is encoded onto the user card. The card
reader reads the number that the access control unit interprets and in
conjunction with a database determines if the user is authorized.
Most magnetic swipe card readers use one of two methods for reading the
card:
* Swipe reader- A card is swiped through a long, narrow slot that is open at
each end. Insert reader- A card is inserted into a small receptacle that
is just large
enough to accommodate the card. The security swipe card may be for general
access, meaning that the card does not provide data about the person using
it, or it may be individually encoded, containing specific information about
the cardholder. Typically, the data on an encoded security swipe card can
include:
name ID number (social security number or other unique number), and
Attachment I- Access Control Technologies:
Access Cards Magnetic Swipe Cards
How the technology works
Attachment I- Access Control Technologies: Access Cards
Page 39 GAO- 02- 687T
access level when different offices within a facility require different
levels of access.
Magnetic swipe card systems perform effectively. However, a magnetic swipe
card system still does not necessarily verify a person; it only confirms
that the person has a card. For this reason, these systems are generally not
considered acceptable as stand- alone systems for high security areas and
require additional controls, such as PINs or biometric identification. Coded
credentials are also vulnerable to counterfeiting and decoding. A card that
is lost or stolen can be used by unauthorized persons. Additionally, if the
authorized access lists are not frequently updated, the potential exists for
persons who no longer have authorization to gain access to a secure area. As
a result, a magnetic swipe card system is considered more effective when
combined with other methods of authentication, such as a keypad entry system
or biometrics.
The most common problem with the magnetic swipe card is the inability to be
read by the card reader. Because they have to be durable enough to withstand
repeated use, magnetic swipe cards are wrapped in a single piece of
protective laminate that protects them from demagnitization, a common cause
of card failure in reader systems. The wrapper also protects them from
cracking or chipping. Even then, wear and tear will affect the card itself;
dirty or scratched cards are also unreadable. The Defense Protective Service
has complained that the problem with its current access control magnetic
swipe cards is that the magnetic strip wears down within a year of use.
Overall there are no user acceptance issues with the magnetic swipe card.
According to the Security Industry Association, the leading vendors are
Mercury, Apollo, and Doavo.
The magnetic swipe cards themselves are very inexpensive at around $1 each.
Card readers cost between $150 and $300 each. Effectiveness
Performance factors User acceptance Vendors
Unit price range
Attachment I- Access Control Technologies: Access Cards
Page 40 GAO- 02- 687T
Source: HID Corp.
Proximity cards are passive, read- only devices. They can be of various
sizes ranging from a token (about the size of a watch battery) to the size
of a credit card.
Proximity cards contain an embedded radio frequency (RF) antenna. The
proximity card reader constantly transmits a low- level fixed RF signal that
provides energy to the card. When the card is held at a certain distance
from the reader, the reader?s RF signal is picked up by the card?s antenna
and absorbed by a small coil inside the card that powers the card?s
microchip. Once powered, the card transmits to the reader a unique
identification code contained in the card?s microchip. The whole process is
completed in microseconds. Cards can usually be read through a purse or
wallet and through most other nonmetallic materials.
The reader can be surface- mounted or concealed inside walls or special
enclosures. It can even function behind glass, plaster, cement, or brick,
depending on the range. It has no openings that can jam or be tampered with.
Card and reader orientation is not critical, and keys or coins held in
contact with the card will not alter its code or prevent accurate readings.
Reading ranges primarily depend on the reader. The larger the reading range,
the larger the size of the reader.
Proximity card systems perform effectively. However, a proximity card system
still does not necessarily verify a person; it only confirms that the person
has a card that was issued to the person he or she claims to be. For this
reason, these systems are generally not considered acceptable as stand-
alone systems for high- security areas, and require additional Attachment I-
Access Control Technologies:
Access Cards Proximity Cards
How the technology works Effectiveness
Attachment I- Access Control Technologies: Access Cards
Page 41 GAO- 02- 687T
controls, such as PINs or biometric identification. Additionally, authorized
access lists must be frequently updated to ensure that access authorization
remains current. As a result, a proximity card system is considered more
effective when combined with other methods of authentication, such as a
keypad entry system or biometrics.
The user has to make sure to hold the card facing the reader. The card can
typically be verified in less than one second.
The contactless nature of the cards reduces the wear and tear associated
with cards requiring contact, such as magnetic swipe cards.
Proximity cards are nonintrusive and very easy to use. If a reader has a
range of 1 meter, then a proximity card can be worn on a clip or chain and
users can gain access by simply passing by the reader.
According to the Security Industry Association, the leading vendors are
Hughes Identification Devices (HID), Indala, and Applied Wireless
Identifications.
Proximity cards cost about $5 to $6; readers can cost up to $750.
Performance factors
User acceptance Vendors Unit price range
Attachment I- Access Control Technologies: Access Cards
Page 42 GAO- 02- 687T
Skeletal image of a smart card. Source: DoD Defense Manpower Data Center.
Smart cards, about the size and shape of a credit card, are used in
accesscontrol systems to verify that the cardholder is the person he or she
claims to be. They are increasingly used in one- to- one verification
applications that compare a user?s biometric (commonly a fingerprint or hand
geometry) to the biometric template stored on the smart card.
Smart cards contain a memory chip to store identification data and often
have a microprocessor to run and update applications. Most smart cards in
use today have the capacity to store 8 kilobytes or 16 kilobytes worth of
information, and cards with 32- kilobyte and 64- kilobyte capacities are
also becoming available.
There are two types of smart cards: contact cards, which work by being
inserted in a smart card reader, and contactless cards, which use radio
frequency (RF) signals and need only be passed within close proximity to a
card terminal to transmit information. Card readers and terminals are
generally very compact and can be mounted on turnstiles and doors.
An advantage of smart cards is that they can support more than one
application. For example, they can be used to authenticate physical access
to multiple facilities or to specific rooms within a facility, and even to
authenticate access to computers or networks. Attachment I- Access Control
Technologies:
Access Cards Smart Cards
How the technology works
Last name First name, Initial
Issue Date Expiration Date
Geneva Conventions Identification Card Rank
Organization Seal Photograph
Organization Status
Pay Grade
Chip
Armed Forces of the United States
Attachment I- Access Control Technologies: Access Cards
Page 43 GAO- 02- 687T
Although the smart card industry has made use of experiences from
traditional magnetic swipe cards, card reliability is not easy to predict.
Physical interfaces for smart cards have been standardized through the ISO,
1 and manufacturers claim that their products pass the ISO reliability tests
meant to simulate ?real life? conditions. However, each implementation of
smart cards varies due to differences in usage patterns, environmental
conditions, software, and readers/ terminals.
A smart card system still does not necessarily verify a person; it only
confirms that the person has a card. For this reason, these systems are
generally not considered acceptable as stand- alone systems for highsecurity
areas and require additional controls, such as PINs, or biometric
identification. As a result, a smart card system is considered more
effective when combined with other methods of authentication, such as a
keypad entry system or biometrics.
One government use of smart cards encountered problems because of network
performance issues. Specifically, the response time for passing information
between the card readers or terminals and the central database was slow, and
officials could not readily verify the identification of users trying to
access these facilities, causing congestion problems. Further testing
revealed that the plastic cards, interfaces or workstation connections, card
readers, and terminals worked effectively- though some interface devices
worked slower than others.
Consistent performance of smart cards relies heavily on cardholder education
about proper card care. Inappropriate user actions (such as punching a hole
in the card or using it to scrape ice off a car windshield) are common and
should be planned for. Glitches in card reader/ terminal software and
hardware can also damage smart cards, and it is important to implement
mechanisms that identify faulty software and hardware.
Public policy organizations continue to be concerned about the data that
will be stored and transferred to databases from smart cards and how
government organizations will use the information. As such, some individuals
may be reluctant to carry one card for multiple purposes.
1 ISO standard 7816.
Effectiveness Performance factors User acceptance
Attachment I- Access Control Technologies: Access Cards
Page 44 GAO- 02- 687T
There is no requirement for smart card technologies to meet a minimum set of
security standards, and smart cards may be vulnerable to various types of
cyber attacks because the devices often support multiple applications that
interface with other computerized products. The National Institute of
Standards and Technology (NIST) and the National Security Agency (NSA) are
currently working on an evaluation program to certify the security of smart
card technologies.
The dominant vendors of smart cards are Gemplus and SchlumbergerSema,
although many vendors offer security systems based on smart cards. Major
smart card system vendors include ActivCard S. A., RSA Security, and Spyrus.
At the federal level, the General Services Administration awarded a $1.5
billion contract in 2000 to five vendors- PRC/ Litton, EDS, 3- G
International, Logicon, and KPMG- to provide federal agencies with a range
of smart card services. Under the contract, more than 140 additional vendors
have been used to supply federal agencies with software, cards, card
readers, terminals, and other peripheral smart card devices- including
Nokia, Microsoft, Rainbow Technologies, and others.
The unit price for smart card technology varies and largely depends on the
applications and security features supported by the device. The price for
the smart card itself can range from about $3 to $30 each. The more
applications supported by the smart card, the higher the unit price. Card
readers or terminals also range in unit price starting from about $16 per
unit. In addition to these costs, organizations incur expenses for managing
the associated databases and software as well as issuing the cards to users
and administering their use. Vendors
Unit price range
Attachment I- Access Control Technologies Keypad Entry Systems
Page 45 GAO- 02- 687T
When used with doors fitted with electric or magnetic locks, keypad entry
systems selectively allow users to enter buildings or other secured areas by
requiring them to first enter a passcode (a PIN or special code). A standard
passcode can be set to allow access to a specific group of individuals, or
multiple passcodes can be adopted for each individual to be assigned a
unique code. When an authorized passcode is entered using the keypad (which
is similar to the numeric keypads of ATM bank machines), the system
activates the electric or magnetic lock, unlocking the door for only a brief
period of time. A database may be automatically updated each time a passcode
is entered to document both successful and unsuccessful access attempts.
Keypad devices typically include a duress function, where a person being
threatened can activate a silent alarm to summon assistance. In some
systems, the threatened user would enter a specific duress code, whereas in
others the threatened users would enter their usual passcode followed by
additional digits. In either case, access would be granted in a seemingly
normal manner, but a silent duress code would be sent to a designated
monitoring station.
A variety of keypads are available, from very simple entry devices to unique
keypads that scramble the numbers differently for each use. Although they
can be used on their own in an access control system, keypads are typically
used in conjunction with an ID card and card reader. Attachment I- Access
Control Technologies
Keypad Entry Systems Keypad Entry Systems
How the technology works
Attachment I- Access Control Technologies Keypad Entry Systems
Page 46 GAO- 02- 687T
In a card- reader- only system, an individual must present something they
have (an authorized card) to gain entry. However, users of a keypad- only
system must only know of an authorized passcode. As such, once a user shares
a legitimate passcode, further use cannot be prevented unless the code is
changed. Also, as users enter their passcodes, they are susceptible to their
codes being ?stolen? by a person looking over their shoulder.
A keypad entry system is considered more effective when combined with a card
system, providing a higher level of security than just the keypad alone.
Keypad entry systems provide a flexible solution for controlling the
movement of groups of people or individuals, as the passcodes can be
disabled when they are no longer appropriate. However, keypad entry systems,
in a manner similar to passwords on computer systems, can be prone to users
forgetting their passcodes; hence, requiring other procedures to pass
through the door.
Keypads are vulnerable to mechanical malfunction as well as vandalism. User
acceptance is high for keypad systems. A selection of vendors taken from the
GSA Schedule includes Radionics, Securitron Magnalock Corp., Ideskco Corp.,
Ultrak, Inc., Vikonics, Inc.
Simple stand- alone keypads, hooked directly to an electric door lock, may
cost less than $200 for all the necessary hardware. More sophisticated
keypad systems that may be part of a network of keypads can cost from $1200
to several thousand dollars. Effectiveness
Performance factors User acceptance Vendors
Unit price range
Attachment I- Access Control Technology: Access Barriers
Page 47 GAO- 02- 687T
Turnstiles and revolving doors are access barriers that can be installed to
continuously control and monitor every individual entering and or exiting a
building. Whereas revolving doors are most often deployed to control the
entry to a building from the street, turnstiles are usually set within the
lobby of a building.
There are a variety of different models of turnstiles that use different
technologies. The traditional physical barrier turnstile is the type used in
many large business facilities, amusement parks, stadiums, and subway
systems. A metal bar is locked into a blocking position to prevent anyone
who has not been authorized via some form of identity verification or form
of payment, such as a token, from walking through the passageway. When
authorization is granted, the bar is released and then relocked until the
next person is granted access.
An optical turnstile can enable complete control of access to a facility
without using a physical barrier. It uses a smart card, proximity card, or
magnetic swipe card system, infrared sensors, and an intelligent control
unit to detect and count persons walking through a lane or passageway.
Access is granted to only one person per card, thus discouraging tailgating.
If a person walks through the passageway without authorization, an alarm is
generated.
Optical turnstiles are easy to use and are almost transparent to users.
Visual or audio indications are given to the user to indicate various
functions such as the open/ closed status of the lane, whether the user is
authorized to pass through the lane or not, or whether an unauthorized
access has been attempted. All activity- including card presentations,
reset, unauthorized card presentation, alarms and access attempts- can be
monitored and logged by the system controlling the turnstiles. Because these
turnstiles function automatically, they only need monitoring by a Attachment
I- Access Control Technology:
Access Barriers Access Barriers
How the technology works
Attachment I- Access Control Technology: Access Barriers
Page 48 GAO- 02- 687T
guard for illegal access attempts or to change lane directions at, for
example, different times of the working day.
Like turnstiles, security revolving doors are used to control access to
buildings by a card reader verification system, but this technology is
usually installed at points of entry from the street. Security revolving
doors use either ultrasonic or weight sensors to detect unauthorized access
such as piggybacking, where two people try to go through the door at the
same time in the same door section, and tailgating, where a person tries to
go through the door at the same time as an authorized person in a different
section. In the event of an unauthorized access, the door will be reversed
so that the unauthorized person remains on the proper side of the door.
Security revolving doors can come equipped with voice annunciators that warn
unauthorized individuals to exit the revolving door and can cause the door
direction to reverse and force the intruder out.
Attachment I- Access Control Technology: Access Barriers
Page 49 GAO- 02- 687T
Turnstiles can detect and accurately report two people walking one behind
the other, very close to each other, as long as they are �? apart. They can
also detect people trying to defeat the turnstile by crawling through or
rolling through on a cart. Turnstiles cannot normally detect two people
walking side- by- side in lockstep, but turnstile lanes are made narrow
enough that this is impractical.
Security revolving doors can increase security by detecting and stopping two
or more people trying to pass through the door simultaneously. When the
scanning system detects unauthorized passage, the doors come to a controlled
stop, and then slowly reverse, thus keeping the violator from passing
through. Violations can be logged and reported.
Optical turnstiles can have a traffic flow rate as high as 30 people per
minute, or 1800 people per hour, per walkway.
Most revolving door systems are capable of processing almost 1,000 passages
per hour in either direction.
Turnstiles with barrier arms are equipped with safety sensors on either side
of the barrier arm, so that if someone tries to run through the turnstile as
the barriers are closing, the barriers will react quickly and retract.
Revolving doors have a number of built- in safeties that prevent people from
being locked in or stuck in the door. They can be operated manually in case
of a power failure. When, for whatever reason, one of the doors jams, the
other door will turn to an open position. And, they are equipped with an
emergency button to stop the door at any desired moment. In addition, the
door wings are collapsible, creating a wide and safe escape route in an
emergency. Only when the collapsed door wing has been manually returned into
the proper position will the door again revolve automatically.
Turnstiles and revolving doors are both very user friendly. They are
unobtrusive and aesthetically pleasing and are effective traffic lanes
through which employees can pass with safety and security.
Turnstile vendors include Smarter Security Systems Inc., Magnetic
Autocontrol Corp., Designed Security Inc., and Gunnebo Omega, Inc.
Effectiveness
Performance factors User acceptance Vendors
Attachment I- Access Control Technology: Access Barriers
Page 50 GAO- 02- 687T
Revolving door vendors include SafeSec Corporation, Horton Automatics, and
Boon Edam.
Optical turnstiles can be purchased for about $43,000 per portal with a card
reader. Individual optical- free barrier turnstiles without readers can cost
from about $1,000 - $5,000.
Revolving doors can cost anywhere from $20,000 to $30,000. Unit price range
Page 51 GAO- 02- 687T
Attachment II: Detection Technologies Detection systems provide a second
layer of security. X- ray machines, metal detectors, and explosive detectors
can be strategically deployed at entry control points to screen individuals
and their belongings for hidden firearms, explosives, and other potentially
injurious objects as they clear the access control system.
Attachment II- Detection Technologies: X- ray Scanning Systems
Page 52 GAO- 02- 687T
X- ray scanners use technology that exposes a person or object to
electromagnetic waves (x- rays), allowing distinct structures to be viewed
within the person or object. Due to their differing material compositions,
items such as metal knives, plastic weapons, and explosive substances will
be displayed differently on a monitor. (This is similar to a medical
diagnostic x- ray system that differentiates between bone and organs.) Based
on the images displayed on the monitor, a human operator can then determine
whether an item of interest warrants further investigation.
There are four primary technologies currently used in x- ray scanning
systems for weapons and chemical detection:
1. Transmission: An x- ray scanner uses only a single x- ray beam, in which
the portion of the beam that penetrates the object under investigation is
detected and used to produce the x- ray image. Because materials have
different densities and compositions, the x- rays allow distinct structures,
particularly metal items, to be viewed within an object.
2. Backscatter: Objects are detected based on the images produced from
reflected x- rays. As a result, plastic weapons, explosives, and drugs
appear bright white on a display monitor.
3. Multi- view (or dual- view): The object under investigation is examined
by two x- ray beams coming in at different angles.
4. Computed Tomography (CT): Known to most people as CAT scanning, this is
the same technology used in hospitals to look deep inside the human body. CT
has been adapted for security applications and is used in airports to scan
checked baggage. Transmission x- ray Attachment II- Detection Technologies:
X- ray Scanning Systems X- ray Scanning Systems
How the technology works
Attachment II- Detection Technologies: X- ray Scanning Systems
Page 53 GAO- 02- 687T
images are taken at many different angles through an object and are put
together to produce a three- dimensional image of the object. This allows
explosives to be specifically identified and discriminated from other
similar, yet harmless, materials.
Different x- ray scanning systems have been developed to examine baggage,
mail, vehicles, and individuals. Large amounts of mail or cargo can be
examined by a fixed system that can scan an entire pallet of cargo for
suspicious items. Larger x- ray systems the size of a truck or an entire
building allow vehicles to be examined. Body scanning devices detect
contraband hidden on a person by utilizing low- power x- rays to see through
clothing, penetrating only a few millimeters below the skin.
The four x- ray technologies have different levels of effectiveness in
detecting various items. Persons familiar with the exact construction of a
particular x- ray system could pack a bag to make a threat item difficult to
recognize. Accordingly, it has been proposed that a combination of
technologies working in unison could significantly improve the detection
ability of screeners.
Transmission technology reveals fine details, such as bomb components, and
exposes situations where an attempt to camouflage or shield an object has
been made. Its strength lies in detecting metallic objects such as
conventional knives and firearms, but it may be difficult to separate the
image of one object from another. Although backscatter technology is not as
effective as transmission technology in identifying metals, it is more
effective in detecting explosives, composite weapons, and organic materials
such as plastics and drugs. A dual- view system provides two different views
of each item, allowing an even clearer view of camouflaged or cluttered
items. The CT technique provides maximum sensitivity and accuracy for
detecting and identifying materials.
Unlike some metal detectors that can be rendered ineffective by
demagnetization, x- ray scanners are not sensitive to their surroundings.
Virtually no clearance is needed around the equipment except for space for
an operator to sit or stand at the controls. However, the size of the actual
equipment may be a factor of effective performance (for example, a truck-
sized scanner may present a space limitation for an average- sized federal
building).
The throughput of x- ray scanning equipment depends on two things: the
amount of clutter in a bag or on a person, and the efficiency of the
Effectiveness
Performance factors
Attachment II- Detection Technologies: X- ray Scanning Systems
Page 54 GAO- 02- 687T
operator. Clutter occurs where several dark items are grouped together in an
x- ray image, so that the actual size and shape of each item cannot be
reasonably detected.
The performance of metal detection systems is closely linked with the
performance of their operators. Operators assist with the placement of items
to be scanned, work the controls, view the monitor, make judgments regarding
each scanned item, and perform any needed manual searches. X- ray scanning
equipment only provides an operator the tools to examine persons, baggage,
or vehicles; it does not identify weapons or explosives for the operator. It
is up to the operator to identify the items of interest from the x- ray
image. Hence, adequate training of the operators to properly identify
weapons and explosives is paramount to the performance of a metal detection
system. Initial training is typically provided by the vendor, but the
practice and experience of the operator is an important factor.
Personal safety issues have been raised, particularly concerns about the
exposure to radiation from x- rays. In the unlikely event that a person is
exposed to radiation from x- ray equipment used for baggage inspection,
studies have shown that this small amount is comparable to that received
during an extended air flight. Additionally, research has found that body
scanning systems use a very low energy level that is considered safe.
Nonetheless, many people find any exposure to x- rays objectionable.
Concerns about the safety of exposing food to x- ray scanners continue to
surface, although in 1989 the World Health Organization released a report
that supports the safeness of food that has passed through an x- ray device
used for cargo. Additionally, with the advancement of x- ray technology to
search baggage for explosives, some individuals continue to be wary of
allowing camera film to pass through scanners that use higher- power x- rays
that could damage film.
New body- scanning equipment used to detect contraband is capable of
projecting an image of a passenger?s naked body. The use of this equipment
may be considered intrusive and raises concerns that a person?s privacy
would be violated. User Acceptance
Attachment II- Detection Technologies: X- ray Scanning Systems
Page 55 GAO- 02- 687T
Vendors include American Science and Engineering (AS& E), PerkinElmer,
Heimann Systems, and Rapiscan.
X- ray scanning devices sized for the detection of materials in baggage
range from about $14,000 to $90,000. Equipment used to scan large volumes of
cargo can range from around $35,000 to $120, 000. Devices for the inspection
of trucks and vehicles range from about $1.7 million to $3.7 million. Body
scanners cost about $100,000.
Regardless of the function, scanning devices using multiple x- ray
technologies (typically a combination of transmission and backscatter) are
generally found in the upper end of the price range. Single- technology
devices tend to fall in the lower end, with the exception of CT scanning
equipment, which costs about $1 million per unit. Vendors
Unit price range
Attachment II- Detection Technologies: Metal Detectors
Page 56 GAO- 02- 687T
Metal detectors are typically used as a physical security mechanism to
locate concealed metallic weapons on a person seeking access to secure
areas. When the detector senses a questionable item or material, an alarm
signal (either a noise, a light, or both) is produced. Because metal
detectors cannot distinguish between, for example, a large metal belt buckle
and a metal gun, trained operators are essential to the deployment of metal
detectors.
A metal detector senses changes to an electromagnetic field generated by the
detector itself. The generated field causes metallic (or other electrically
conductive) objects in the proximity to produce their own distinct magnetic
fields. The size, shape, electrical conductivity, and magnetic properties of
an object are the significant factors used by metal detection technologies
to distinguish metal from other detected objects and materials.
Two types of metal detection equipment are commonly used for access control:
portal (walk- through) and handheld detectors. Portal detectors are stand-
alone structures resembling a deep door frame. Conventional portal detectors
alert an operator when metal objects have passed through the portal, but do
not indicate the location of the metal objects. However, some of the newer
portal systems use a light bar that is located along the side of the portal
to pinpoint zones of the body where the metal objects are detected.
Attachment II- Detection Technologies:
Metal Detectors Metal Detectors
How the technology works
Attachment II- Detection Technologies: Metal Detectors
Page 57 GAO- 02- 687T
After a person who has passed through a portal system has set off an alarm
signal, an operator will typically use a handheld metal detector to more
accurately locate the object that caused the alarm. These devices are
battery- operated and lightweight, allowing the operator to move the wand
end of the device around (and within a few inches of) the person?s body.
When an irregularity in the magnetic field is identified, the handheld
device typically emits a loud noise. The operator is then responsible for
judging whether the intensity of the signal warrants further investigation.
Metal detectors are considered a mature technology that can accurately
detect the presence of most types of firearms and knives. However, they are
typically not accurate when used on objects that contain a large number of
different materials (such as purses, briefcases, and suitcases). Government
security officials have also reported frequent false alarms and incomplete
follow- up scans by security personnel.
Both the portal and handheld metal detectors are designed for use in close
proximity situations.
Portal metal detectors are extremely sensitive to interference from
conflicting signals of nearby objects. As such, their effectiveness can be
easily degraded by a poor location (directly under fluorescent lights or
metal air ducts); the nearby use of electromagnetic equipment (such as an
elevator); movement from one location to another, and even the placement of
a nearby metal trash can. The initial calibrations are generally made by the
vendor when the detector is installed. However, facilities often must make
adjustments based on results gained through use and their particular
security requirements, which determine levels of equipment sensitivities.
Unlike portal metal detectors, handheld metal detectors are not nearly as
sensitive to surrounding metal objects. However, the performance of portal
metal detectors tends to vary on a daily basis and requires frequent
adjustment.
A successful metal detection system depends on well- trained and motivated
operators. Typically, an effective operator should be able to process
between 15 and 25 people per minute through a portal detector. (This does
not include investigation of alarms or other delays.) Traffic flow is
generally driven by three factors: the number of devices, the rate at which
individuals arrive, and the motivation of individuals to cooperate
Effectiveness
Performance factors
Attachment II- Detection Technologies: Metal Detectors
Page 58 GAO- 02- 687T
with the established procedures. Cooperative individuals can typically be
scanned with a handheld detector in about 30 seconds.
Some people, particularly those with certain medical devices such as
pacemakers and implantable cardioverter/ defibrillators, fear the possible
side effects of being subjected to the magnetic field of metal detectors.
Because metal detectors emit an extremely weak magnetic field, interactions
with walk- through and handheld devices are unlikely to cause clinically
significant symptoms. Nevertheless, in 1998 the U. S. Food and Drug
Administration began working to address these concerns with both the
manufacturers of medical devices and the manufacturers of metal detectors.
Additional issues have been raised regarding the use of handheld metal
detectors. Because these devices are passed very closely over the body of
individuals who have been selected for further screening, they can be
perceived as potential tools for harassment and intimidation. Men wearing
turbans and women in undergarments with metal components are examples of two
cases that have caused concerns related to discrimination and privacy.
There are a number of vendors, including CEIA, Control Screening, LLC,
Garrett Metal Detectors, Heimann Systems, Ranger, and Rapiscan.
Portal metal detectors vary widely in price, ranging from about $1,000 to
about $30,000. Models in the higher price ranges offer enhanced
capabilities, while the lower- range devices may have limited sensitivity
and detection capabilities.
Most handheld metal detectors on the market range from about $20 to about
$350. As with the portal detectors, capabilities increase along with the
price. User acceptance
Vendors Unit price range
Attachment II- Detection Technologies: Explosive Detection Systems
Page 59 GAO- 02- 687T
Several different technologies are currently used to detect explosives:
trace detection, quadrupole resonance analysis, and x- ray scanning
machines.
The most widely used technology is trace detection, which uses ion mobility
spectrometry (IMS) to detect and identify both trace particles and vapors of
explosives, narcotics, chemical warfare agents, and toxic industrial
chemicals. Trace explosive detection systems can detect a trace of chemicals
used in explosives as small as a millionth of a gram. Trace explosive
detection equipment comes in a variety of sizes, depending on whether it is
to be used to detect chemicals concealed on individuals, in containers,
packages, or in or under vehicles.
The handheld explosive detection unit can be used almost anywhere. The
device, which is small and lightweight, is capable of detecting over 30
substances in seconds. Attachment II- Detection Technologies:
Explosive Detection Systems Explosive Detection Systems
How the technology works
Attachment II- Detection Technologies: Explosive Detection Systems
Page 60 GAO- 02- 687T
Tabletop units are becoming common for the detection of explosives concealed
in baggage. For these units, which also use IMS technology, security
personnel rub the outside of a bag, such as a lock or handle or zipper, with
a cotton swab and then insert the swab into a machine that heats the swab,
turning the sample into vapors. The unit alerts the operator to the presence
of any explosive traces that warrant further examination. Some systems
create different sounds to indicate the relative density of the contraband
detected and indicate probable drug or gun type materials.
Portal explosive detection units take in the air from around the subject as
he or she walks through to check for explosive residue. When explosives are
detected, the system sets off a visual and audible alarm, and lists the
material identified. It can detect organic and inorganic contraband on the
body and clothing.
Quadrupole resonance analysis is another type of technology used to detect
explosives. Similar to magnetic resonance imaging (MRI) used in hospitals,
this technology is typically used to scan belongings and baggage. These
units resemble x- ray machines used for the same purpose.
X- ray machines can also be used to detect explosives and are available to
scan belongings, people, or moving and stationary vehicles.
While the technology is capable of detecting most military and commercially
available explosives- including TNT, plastic explosives, high- vapor
explosives, and chemical warfare agents- most devices are Effectiveness
Attachment II- Detection Technologies: Explosive Detection Systems
Page 61 GAO- 02- 687T
designed to detect only a subset. Others have slow processing rates for
larger items.
As with other technologies, explosion detection equipment also has a small
percentage of false alarms.
All explosive detection systems have specific sampling guidelines for
specific applications. This is important because some systems rely almost
entirely on the skills of the operators.
Handheld detection devices are lightweight and ready to operate within 1
minute from the time they are turned on. They are easy to use, and provide
readings within seconds. The use of these devices near idling cars has been
shown to cause interference and require frequent recalibrations.
Tabletop trace detection units are self- calibrating and also provide
readings within seconds.
Baggage x- ray machines also provide rapid readings and can process an
average of about 550 bags to 800 bags per hour.
Portals are capable of processing seven passengers per minute. Vehicle
screening detectors take approximately 1 minute.
Explosive detection units are noninvasive and carry no health concerns. The
following vendors appear on the GSA schedule: Ion Track, Barringer
Instruments Inc., SAIC, Raytheon, InVision Technologies Inc, L- 3
Communications, Scintrex Trace Corporation, and Rapiscan.
A handheld device can cost between $20,000 and $45, 000. A tabletop
detection device can cost from $20,000 to $65,000. A portal system can cost
from $80,000 to $400,000. The largest baggage x- ray units are priced from
$110, 000 to $1.3 million. The medium size x- ray units for smaller packages
range from $100, 000 to Performance factors
User acceptance Vendors
Unit price range
Attachment II- Detection Technologies: Explosive Detection Systems
Page 62 GAO- 02- 687T
$235,000. Standalone units for personal belongings are priced from $30,000
to $50,000.
Page 63 GAO- 02- 687T
Attachment III: Intrusion Detection Technologies Intrusion detection systems
serve to alert security staff to react to potential security incidents.
These systems are designed to identify penetrations into buildings through
vulnerable perimeter barriers such as doors, windows, roofs, and walls.
These systems use highly sensitive sensors that can detect an unauthorized
entry or attempted entry through the phenomena of motion, vibrations, heat,
or sound.
Closed circuit television (CCTV) is an integral part of intrusion detection
systems. These systems enable security personnel to monitor activity
throughout a building. Intrusion detection technologies can also be
interfaced with the CCTV system to alert security staff to potential
incidents requiring monitoring.
When an intrusion is sensed, a control panel to which the sensors are
connected transmits a signal to a central response area, which is
continually monitored by security personnel. The sensor- detected incident
will alert security personnel of the incident and where it is occurring. By
interfacing these technologies, security personnel can initially assess
sensor- detected security events before determining how to react
appropriately.
Attachment III- Intrusion Detection Technologies: Closed Circuit Television
Page 64 GAO- 02- 687T
Analog CCTV surveillance system.
Source: Pittway Corporation.
CCTV is a visual surveillance technology designed for monitoring a variety
of environments and activities. CCTV systems typically involve a dedicated
communications link between cameras and monitors. Digital camera and storage
technologies are rapidly replacing traditional analog systems.
CCTV provides real- time or recorded surveillance information to help in
detecting and reacting to security incidents. A CCTV system can also be used
to prevent security breaches by allowing remotely stationed security
personnel to monitor access control systems at entry points to secure areas.
Other advantages to using CCTV include deterring criminal activity,
promoting a safe and secure work environment, enhancing the effectiveness of
security personnel, discouraging trespassing, providing video evidence of
activities occurring within the area, and reducing civil liability.
A CCTV system involves a linked system of cameras able to be viewed and
operated from a control room. Cameras come in two configurations: fixed made
or pan- tilt- zoom mode. In pan- tilt- zoom mode they can either
automatically scan back and forth or be controlled by an operator to focus
on particular parts of a scene.
Some systems may involve more sophisticated technologies such as night
vision, computer- assisted operation, and motion detection systems. A camera
that is integrated with a motion detection system would, for example, enable
alerted security staff to remotely investigate potential security incidents
from a central control center. Other sophisticated CCTV systems incorporate
technologies that make possible features such as the multiple recording of
many cameras, almost real- time pictures over Attachment III- Intrusion
Detection
Technologies: Closed Circuit Television
Closed Circuit Television (CCTV)
How the technology works
Attachment III- Intrusion Detection Technologies: Closed Circuit Television
Page 65 GAO- 02- 687T
telephone lines, low- light cameras, 360- degree- view cameras, the
switching of hundreds of cameras from many separate control positions to
monitors, immediate full- color prints in seconds from a camera or
recording, and the replacement of manual controls by simply touching a
screen. CCTV is also sometimes used to capture images for a facial
recognition biometric system.
The clarity of the pictures and feed is often excellent, with many systems
being able to recognize a cigarette packet at a hundred meters. The more
expensive and advanced camera systems can often work in pitchblackness,
bringing images up to daylight level.
However, CCTV systems are not considered to be suitable for highsecurity
areas that require security staff to be present at entry control points.
Also, inattention to monitors by security personnel, as discussed below, is
a common problem.
The biggest problem concerning CCTV is proper installation. Since cameras
vary in size, light sensitivity, resolution, type and power, it is essential
to understand the target area before procuring a camera. Important aspects
to be considered are lighting, environment, and mounting options. Because
insufficient attention is often paid to all of these aspects before products
are selected and installed, many CCTV systems do not work properly. Just how
important proper lighting is is reflected in the Defense Protective
Service?s having installed 98 percent of their CCTV cameras in well- lit
areas.
While CCTV can be used to supplement and reinforce security staff, using
CCTV as an active surveillance tool is often not effective. Studies have
shown that because monitoring video screens is both boring and mesmerizing,
the attention span of a person watching and assessing a CCTV monitor
degrades below acceptable levels after 20 minutes. CCTV is more effective
when used, for example, at control points to actively allow or disallow
individuals through a particular door on the basis of the security staff?s
recognition of the CCTV image of the individual.
Most CCTV systems have all their connected cameras record continuously. The
result is an abundance of video material that must be manually reviewed if
an incident that cannot be narrowed down to a particular time is being
investigated. However, by using cameras that are triggered to turn
Effectiveness
Performance factors
Attachment III- Intrusion Detection Technologies: Closed Circuit Television
Page 66 GAO- 02- 687T
on by the occurrence of motion within their field of view, the amount of
video that is recorded is greatly reduced and facilitates faster searches.
Whereas analog storage is space consuming and human intensive, digital
technology allows large amounts of data to be captured, compressed,
recorded, and automatically stored and managed so that recorded events can
be tracked and located by date and time.
CCTV has raised much concern over privacy issues. Apprehensions are
generally based on a fear that CCTV will be used for purposes other than for
which they were intended. Examples of these concerns are that CCTV systems:
may be used to monitor an individual?s actions in real time or over a
period of time;
may be used by employers to monitor employees? performance, including when
they arrive and leave work;
may enable security personnel to indulge in voyeurism by especially
focusing on attractive individuals; and
may be used to arbitrarily monitor individuals of a particular race or
ethnic background.
Apprehensions such as these have hindered organizations from exploiting the
full potential of CCTV towards enhancing security. The Capitol Police, for
example, does not plan to install many more cameras in its internal spaces
because of the sensitivity of its members to internal surveillance.
The GSA schedule lists the following CCTV vendors: Panasonic Security
Systems Group, Extreme CCTV Inc., Ultrak Inc., and Silent Witness
Enterprises Ltd.
A fully integrated CCTV system for physical access surveillance can cost
from $10,000 to about $200,000, depending on the size of the entrance and
the degree of surveillance required for monitoring the area. For additional
CCTV equipment, cameras can cost about $125 to $500. Cameras with advanced
technological features can cost up to $2,300. Monitors can cost between $125
and about $1,000. Recorders can cost between $400 and $2,700, and a video
control system (remote controller and accessories) between $3,000 and
$12,000. User acceptance
Vendors Unit price range
Attachment III- Intrusion Detection Technologies: Closed Circuit Television
Page 67 GAO- 02- 687T
Source: Silicon Technologies, Inc.- Window Vision (c) 2002.
Attachment III- Intrusion Detection Technologies: Intrusion Sensors
Page 68 GAO- 02- 687T
Source: National Institute of Justice.
Electronic intrusion detection systems are designed to detect penetrations
into secured areas through vulnerable perimeter barriers such as walls,
roofs, doors, and windows. Detection is usually reported by an intrusion
sensor and announced by an alarm (typically to a central response area). The
intrusion alarm must then be followed by an assessment to determine the
proper response. CCTV is typically used in internal assessments to determine
the validity of the alarm.
A variety of technologies have been developed for the detection of
intrusions:
Line sensors use cables that are either placed above ground or buried in the
ground. When positioned just outside a building wall, they can detect both
prowlers and tunneling activity. Some lines are sensitive to magnetic or
electric disturbances that are transmitted through the ground to the sensing
elements, while others respond to changes in pressure from an intruder?s
footstep or vehicle.
Video motion detectors transform the viewing- only ability of CCTV cameras
into a tracking and alarm system. By monitoring the video signals, the
sensors detect changes caused by the movement of an object within the
video?s field of view. Sometimes only a portion of the total field of view
is monitored for motion. The size of the moving object or its speed (for
example, blowing debris or a flying bird) can sometimes be used to
distinguish a person from other objects in motion.
Balanced magnetic switches are an extension of the conventional magnetic
switch used on doors and windows in a home security system and are widely
used to indicate whether a door is open or closed. Attachment III- Intrusion
Detection
Technologies: Intrusion Sensors
Intrusion Sensors How the technology works
Attachment III- Intrusion Detection Technologies: Intrusion Sensors
Page 69 GAO- 02- 687T
Conventional magnetic switches can be defeated by placing a steel plate or
magnet over the switch, allowing the door to be opened while keeping the
switch closed. Balanced magnetic switches activate an alarm if this defeat
tactic is used.
Sonic and vibration sensors detect intrusion indicators such as the sound
and movements of breaking glass or wood at windows and walls. Because they
are typically used in rooms during timeframes when legitimate access is not
expected, these sensors can also be used to detect the motion of a person
walking into or within a designated area. While changes in sound waves are
typically detected by sonic sensors, vibrations are typically detected by
the use of microwave radiation or infrared (IR) light (both of which are
invisible to the naked eye). Microwave sensors generate a detection zone by
sending out a continuous field of microwave energy. Intruders entering the
detection zone cause a change in this field, triggering an alarm. IR
technology operates in two methods:
1. Active IR sensors inject infrared rays into the environment to detect
changes. They generate an alarm when the IR light beam (similar to that used
in a TV remote controller) is broken. Multiple active IR beams are often
used at gates and doors to create a web of rays that make the system more
impenetrable.
2. Passive IR sensors, also known as pyroelectric sensors, operate on the
fact that all humans (and animals) generate IR radiation according to their
body temperatures. Humans, having a skin temperature of around 93�F,
generate IR energy with a wavelength between 9 and 10 micrometers. Passive
IR sensors are therefore typically set to detect a range of 7 to 14
micrometers.
Sensor technology has been relied on for many years as an effective
countermeasure to security breaches. However, this technology is susceptible
to nuisance alarms or false alarms not caused by intruders. Depending on the
technology used, disturbances that contribute to nuisance alarms can be
generated by animals, blowing debris, lightning, water, and nearby train or
truck traffic. Nuisance alarms can be mitigated by adjusting a sensor?s
sensitivity level and by careful routing of signal cables.
Because these intrusion detection systems operate on electricity, any
disturbance in the electrical power will affect their performance. Special
Effectiveness
Performance factors
Attachment III- Intrusion Detection Technologies: Intrusion Sensors
Page 70 GAO- 02- 687T
design considerations must be given to the routing and protection of power
and signal cables to prevent exposure to tampering and environmental wear
and tear.
Careful placement of sensors is also critical to their success. Some
vibration sensors should not be mounted directly on window glass, as the
mounting adhesive may not be designed to withstand long exposures to heat,
cold, and condensation. Because passive IR sensors detect changes in
temperature, their sensitivity would decrease if placed in rooms that would
approach the same temperature as the human body. Manufacturers?
specifications for each sensor technology should be heeded to ensure maximum
performance.
Doors and windows that have been equipped with intrusion detection devices
cannot be propped open for circulation of fresh air. A building with a large
number of windows cannot be fully secured with an intrusion detection sensor
unless all windows are equipped with the devices.
For the technologies discussed above, The National Institute of Justice?s
Perimeter Security Sensor Technologies Handbook 1 lists the following
vendors: ADT Security Systems, Advantor, DAQ Electronics, Detection Systems,
Inc., GYYR, Microwave Sensors, Millennium Sensors, Presearch, Safeguards
Technologies, Scantronic, Senstar, South West Microwave, Stellar Security
Products, Vindicator, and Visonic LTD.
Line sensor cables range from about $300 to $750 for 100 meters. Line sensor
detection systems are available for about $1,000.
Video motion detector cameras range from about $150 to $1, 500. Balanced
magnetic switches range from about $100 to $289. Simple microwave sensors
are available for about $30, while comprehensive microwave detection systems
range from about $400 to $1,000.
1 http:// www. nlectc. org/ perimetr/ full2. htm
User acceptance Vendors
Unit price range
Attachment III- Intrusion Detection Technologies: Intrusion Sensors
Page 71 GAO- 02- 687T
Infrared sensors range from about $25 to $200. (310150)
*** End of document. ***