The increasing use of automated information systems together with
our pervasive use of computers has greatly simplified our lives,
while making us overwhelmingly dependent on computers and digital
networks. Technological achievements over the past decade have
resulted in improved network services, particularly in the areas
of performance, reliability, and availability, and have significantly
reduced operating costs due to the more efficient utilization
of these advancements.
mechanisms recently developed requires users to perform a particular
action and then some behavior of that action is examined. The
traditional method of signature verification falls in this category.
Handwritten signatures are extremely difficult to forge without
assistance of some copier.
A number of
identification solutions based on verifying some physiological
aspect - known as BIOMETRICS - have emerged. Biometrics, the physical
traits and behavioral characteristics that make each of us unique,
are a natural choice for identity verification. Biometrics is
an excellent candidate for identity verification because unlike
keys or passwords, biometrics cannot be lost, stolen, or overheard,
and in the absence of physical damage they offer a potentially
foolproof way of determining someone's identity. Physiological
(i.e., static) characteristics, such as fingerprints, are good
candidates for verification because they are unique across a large
section of the population. Indispensable to all biometric systems
is that they recognize a living person and encompass both physiological
and behavioral characteristics.
Biometrics is of two kinds. One deals with the physical traits
of the user and the other deals with the behavioral traits of
the user. Retinal scanning, fingerprint scanning, face recognition,
voice recognition and DNA testing comes under the former category,
while typing rhythm comes under the later category.
Physiological characteristics such as fingerprints are relatively
stable physical features that are unalterable without causing
trauma to the individual. Behavioral traits, on the other hand,
have some physiological basis, but also react to a person's psychological
Most systems make use of a personal identification code in order
to authentication the user. In these systems, the possibility
of a malicious user gaining access to the code cannot be ruled
out. However, combing the personal identification code with biometrics
provides for a robust user authentication system.
using the typing rhythm of the user on keyboard or a keypad takes
advantage of the fact that each user would have a unique manner
of typing the keys. It makes use of the inter-stroke gap that
exists between consecutive characters of the user identification
any system for authenticity, one needs to consider the false acceptance
rate and the false rejection rate.
The False Acceptance Rate (FAR)
is the percentage of un-authorised users accepted by the system
and the False Rejection Rate (FRR) is the percentage of authorised
users not accepted by the system. An increase in one of these
metrics decreases the other and vice versa. The level of error
must be controlled in the authentication system by the use of
a suitable threshold such that only the required users are selected
and the others who are not authorised are rejected by the system.