Page 975 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

the retina, the iris remains relatively unchanged throughout a person’s
life (barring eye damage or illness). Iris scans are considered more

acceptable by general users than retina scans typically because scans
can occur from far way. Scans can often be done from 6 to 12 meters
away (about 20 to 40 feet). However, some scanners can be fooled
with a high-quality image in place of a person’s eye. Additionally,
accuracy can be affected by changes in lighting and the usage of some
glasses and contact lenses.

Palm Scans Palm scanners scan the palm of the hand for
identification. They use near-infrared light to measure vein patterns in
the palm, which are as unique as fingerprints. Individuals simply place
their palm over a scanner for a few seconds during the registration
process. Later, they place their hand over the scanner again for
identification. As an example, the Graduate Management Admissions
Council (GMAC) uses palm vein readers to prevent people from taking
the test for others and also to ensure that the same person reenters the

testing room after a break.

Hand Geometry Hand geometry recognizes the physical
dimensions of the hand. This includes the width and length of the
palm and fingers. It captures a silhouette of the hand, but not the
details of fingerprints or vein patterns. Hand geometry is rarely used
by itself since it is difficult to uniquely identify an individual using this

method.

Heart/Pulse Patterns Measuring the user’s pulse or heartbeat
ensures that a real person is providing the biometric factor. It is often
employed as a secondary biometric to support another type of
authentication. Some researchers theorize that heartbeats are unique
between individuals and claim it is possible to use electrocardiography
for authentication. However, a reliable method has not been created or

fully tested.

Voice Pattern Recognition This type of biometric authentication
relies on the characteristics of a person’s speaking voice, known as a
voiceprint. The user speaks a specific phrase, which is recorded by the
authentication system. To authenticate, they repeat the same phrase
and it is compared to the original. Voice pattern recognition is