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Biometric Fingerprint Identification

1. INTRODUCTION

Positive identification of individuals is a very basic societal requirement.

Reliable user authentication is becoming an increasingly important task in the web –

enabled world. The consequences of an insecure authentication system in a

corporate or enterprise environment can be catastrophic, and may include loss of

confidential information, denial of service, and compromised data integrity. The value

of reliable user authentication is not limited to just computer or network access.

Many other applications in every day life also require user authentication, such as

banking, e-commerce, and could benefit from enhanced security.

In fact, as more interactions take electronically, it becomes even more important

to have an electronic verification of a person’s identity. Until recently, electronic

verification took one of two forms. It was based on something the person had in their

possession, like a magnetic swipe card, or something they knew, like a password. The

problem is, these forms of electronic identification are not very secure, because they can

be given away, taken away, or lost and motivated people have found ways to forge or

circumvent these credentials.

The ultimate form of electronic verification of a person’s is biometrics.

Biometrics refers to the automatic identification of a person based on his/her

physiological or behavioral characteristics such as finger scan, retina, iris, voice scan,

signature scan etc. By using this technique physiological characteristics of a person can

be changed into electronic processes that are inexpensive and easy to use. People have

always used the brain’s innate ability to recognize a familiar face and it has long been

known that a person’s fingerprints can be used for identification.

Dept. of EEE MESCE, Kuttippuram1


2. IDENTIFICATION AND VERIFICATION SYSTEMS

A person’s identity can be resolved in two ways: identification and

verification. The former involves identifying a person from all biometric measurements

collected in a database and this involves a one-to-many match also referred to as ‘cold

search’. “Do I know who you are”? is the inherent question this process seeks to

answer. Verification involves authenticating a person’s claimed identity from his or her

previously enrolled pattern and this involves a one to one match. The question it seeks

to answer is, “Are you claim to be?”

2.1 VERIFICATION

Verification involves comparing a person’s fingerprint to one that pass

previously recorded in the system database. The person claiming an identity provided a

fingerprint, typically by placing on a capacitance scanner or an optical scanner. The

computer locates the previous fingerprint by looking at the person’s identity. This

process is relatively easy because the computer needs to compare two fingerprint

records. The verification process is referred as a ‘closed search’ because the search field

is limited. The second question is “who is this person?” This is the identification

function, which is used to prevent duplicate application or enrollment. In this case a

newly supplied fingerprint is supplied to all others in the database. A match indicates

that the person has already enrolled/applied.

2.2 IDENTIFICATIONThe identification process, also known as an ‘open search’, is much more

technically demanding. It involves many more comparisons and may require

differentiating among several database fingerprints that are similar to the objects.



3. BIOMETRIC SYSTEMS AND DEVICES

A biometric system is a combined hardware/software system for biometric

identification or verification. Main functions of a biometric system are as follows:

Receive biometric samples from an enroller or candidate.

Extract biometric feature from the sample.

Compare the sample of the candidate with stored templates from

individuals.

Indicate identification or verification upon the result of the previous

comparison.

Biometric devices have three primary components:

One is an automated mechanism that scans and captures a digital or analog

image of a living characteristic.

The second handles comparison of the image with the stored data.

The third interfaces with application systems.

These pieces may be configured to suit different situations. A common

issue is where the stored images reside; on a card presented by the person being verified

or at host computer. Recognition occurs when an individual’s is matched with one of a

group of stored images.



4. BIOMETRIC ACCURACY

Biometric accuracy is the system’s ability of separating legitimate

matches from imposters. There are two important performance characteristics for

biometric systems.

False rejection is the situation when a biometric system is not able to verify

the legitimate claimed identity of an enrolled person.

False acceptance is a situation when a biometric system wrongly verified the

identity by comparing biometric features from not identical individuals.

False Rejection Rate (FRR) refers to the statistical probability that the

biometric system is not able to verify the legitimate claimed identity of an

enrolled person, or fails to identify an enrolled person.

False Acceptance Rate (FAR) refers to the statistical probability of false

Acceptance or incorrect verification. In the most common context, both

False Rejection and False Acceptance represent a security hazard.



5. FINGERPRINT VERIFICATION

Fingerprinting is probably the best-known biometric- method of identification

used for 100 years. Advances in computer technology and communication networks

have made even huge fingerprint databases available for instant searches.

Among all the biometric techniques, fingerprint-based Identification is the oldest

method that has been successfully used in numerous applications. Everyone is known to

have unique, immutable fingerprints. A fingerprint is made of a series of ridges and

furrows on the surface of the finger. The uniqueness of a fingerprint can be determined

by the pattern of ridges and furrows as well as minutiae points. Minutiae points are local

ridge characteristics that occur at either a ridge bifurcation or a ridge ending.

There are a variety of approaches to fingerprint verification. Some try to emulate

the traditional police method of matching minutiae, others are straight pattern matching

devices, and some adopt a unique approach all of their own, including thermal

properties and ultrasonic. Finger-scan technology is the leading biometric authentication

technology in use today with the greatest variety of fingerprint devices presently

available. This is partially due to the historical use of the fingerprint in law enforcement

as well as the fact that the technology lends itself to a more affordable solution.

VIEW OF A FINGER PRINT



6. FINGERSCAN

Fingerscan is an authentication terminal which verifies a persons identity from

their finger image. When a user places their finger on the terminals scanner the image is

electronically read, analysed, and compared with a previously recorded image of the

same finger which has been stored in the fingerscan database. Users call up their finger

image by keying in an identification number. This ID number does not need to be

classified as it is not part of the security system it simply retrieves the image that will be

compared to the users finger scan.

Fingerscan contains its own database of finger images (called templates), user

privileges and authorities, and maintains a log of every transaction and message which

it records. The system can be accessed through a laptop, networked to a PC, or

connected via a modem to a remote host computer.

6.1 THE TECHNOLOGY BEHIND FINGERSCAN

Fingerscan is a biometrics product which involves using some unique biological

characteristic or physical property of an individual to verify that persons claimed

identity. Biometrics-based identification replaces systems which rely on something a

person has in their possession, such as a key or ID card, or something a person knows,

such as a password or privileged information. The imaging process is based on digital

holography, using an electro-optical scanner about the size of a thumbprint. The scanner

reads three-dimensional data from the finger such as skin undulations, and ridges and

valleys, to create a unique pattern that is composed into a template file and recorded in

the fingerscan database.



The pattern is not a fingerprint and a fingerprint cannot in any way be created

from the template. A template can only be compared with a newly presented live finger

image and not with other templates. One reason for this is that the data capture process

used to create a template is random. If two templates were created one after another for

the same finger, each template would be different. This eliminates the possibility of

database matching and enhances users privacy.

6.2 THE ALGORITHMS

Fingerprint classification can be viewed as a coarse level matching of the

fingerprints. As input fingerprint is matched at a coarse level to one of the prespecified

types and then, at a finer level, it is compared to the subset of the database containing

that type of fingerprints only.

An algorithm is developed to classify fingerprints into five classes, namely,

whorl, right loop, arch and tented arch. The algorithm separates the number of ridges

present in four directions (o degree, 45 degree, 90 degree and 135 degree) by filtering

the central part of a fingerprint with a bank of Gabor filters. This information is

quantized to generate a finger code which is used for classification. More recently, it

has become possible to scan a person’s fingerprint into virtual storage in a computer

with the aid of laser technology. In order to prove identification, a person’s fingerprint

will be scanned again in the future by a similar device, and a match of print to name is

verified through information system.



6.3 SYSTEM FUNCTIONS

The major FINGERSCAN functions are:

Enrolment

Verification

Time Zones

Door access

Template management

Enrolment

Enrolment is the process of scanning a finger to create an image which is stored

as a template. Each time the user places his or her finger on the scanner the image is

compared to the one represented by the template to verify their identity.

A user with enrolment authority carries out enrolment at designated fingerscan

units. The process takes approximately 25 seconds and the resultant template may be

stored in various places: in the unit itself, on a personal computer, in a mainframe

computer, on a smart card, and so on.

Each user enrolled is allocated a unique ID number, which they use to call up

their template before scanning their finger. No ID number is required where the

template is stored on a smart card. Up to three fingers can be enrolled against the same

ID number to provide users with more than one verification option. Ideally, one finger

on each hand should be enrolled so that if the user injures the finger they usually use for

verification an alternate image is available.



This feature also provides for multi-person control, for example, if verification

from two users is required to open a safe. In this situation fingerscan can be

programmed to require up to four fingers with different ID numbers to be verified

before access is granted.

Verification

Verification is carried out when a user either enters their ID number, or inserts

their smart card in a smart card reader, and then immediately places their finger on the

reader platen. Verification takes about .5 of a second.

Verification for individual users can be set at various threshold levels to account

for users who may have very fine, worn, or damaged fingers. In this event reducing

their verification threshold can enhance the ease of use.

The overall system verification threshold can be lowered in situations where

little or no security is required, for example, time and attendance applications. In this

situation it may be more acceptable to give a false acceptance than a false rejection.

Time zones

Up to thirty global or individual time zones can be defined in fingerscan. Each

user can have up to two active time zones at any time. Users are allocated a default time

zone at enrolment, which can be changed by the system supervisor or from the host

computer.



Door Access

A door access list defines which users have access to the facilities controlled by

the fingerscan unit. The list can be used in conjunction with time zones to restrict access

at certain times. The host computer system can control and manage the door access list

and the distribution of templates to each fingerscan unit.

Template Management

Templates can be stored in the fingerscan unit, and/or a host computer, and/or a

smart card. Each fingerscan unit has 512Kbytes of non-volatile memory which stores up

to 300 templates. The memory can be expanded to 1.5Mbytes which will store more

than 1100 templates. Templates are stored with a last used date status. If the memory

becomes full, the last used templates will be held locally in the fingerscan unit and the

main template database will be held in the host computer. The host will transmit

templates to individual units if the requested template is not found locally.

Templates can be deleted by user with Manager or Supervisor status either from

the host computer or locally at each fingerscan unit. Templates can be exchanged

between a fingerscan unit and the host computer over fixed communications or modem

links, or locally to and from a laptop. A template created by the fingerscan unit can be

used on any other unit when loaded.

6.4 MANAGEMENT CONTROL

Fingerscan has four levels of management control:

User

A user submits a finger for verification after entering an ID number



Enroller

An enroller has user status and can also enrol users onto the system.

Supervisor

A supervisor has enroller status and can also perform initial system set up

procedures, set time zones, set alarm codes, and add and delete templates.

Manager

A manager has supervisor status and can also perform a total system reset, and

disable the supervisors ability to change the setup.

Transaction Log

A transaction log records every use of a fingerscan unit, the time it was used,

and the result. The log will hold at least the last 1000 transactions and will wrap around

when it becomes full. The transaction log cannot be erased except on a total system

reset by a user with Manager authority. Each transaction is allocated a consecutive audit

number that does not wrap around. The number will only be reset to 1 on a total system

reset.

6.5 SECURITY

Fingerscan provides an audit trail of the date and time a user accessed the unit,

the reason for access, and the result. With a 0.0001% probability of a false acceptance

fingerscan provides a level of security which cannot be achieved by any knowledge or

token based system.

Template security

Before a user can do any action on a template such as enrol, delete, or transfer,

they must first have their identity verified by FINGERSCAN in the usual way. In doing

this, a record is added to the transaction log. Only users with Supervisor or Manager

authority levels can access the template database.



Software Security Control

A password option in the communications setup secures the data flow to a host

computer. When each fingerscan unit is initialised by the remote host, the host will

generate and download to the unit a unique Computer Generated Access Code (CGAC)

of at least six digits. For all subsequent communications the host will check the CGAC

before starting the session and then change the CGAC immediately prior to logging off.

The CGAC can always be overridden by a Manager or Supervisor finger verification.

This is only likely to be required if the fingerscan unit is being accessed via a laptop PC.

Hardware security control

The processor board in the processor unit is located inside a metal box which

can be fitted with a tamper alarm if required. The processor unit should always be

located inside the secure area in locations where fingerscan is providing access or other

security control. Fingerscan controls the activation of electric locks or strikes from the

processor board so the unit cannot be hot-wired from outside.

Alarms Control

Send an alarm directly to a monitoring company, dialer, modem, siren, and so

on, and allow authenticated users to cancel and reset zone alarms and activate

and deactivate building services such as air conditioning and lighting.

Record alarms in the fingerscan transaction log.

Support a request to exit (REX) verification which allows users to open a door

from the inside. This can be used to monitor door forced alarms.

Door Lock Control

Fingerscan can directly control a door lock strike after verification of a user.



Real Time Clock

Fingerscans real time clock is protected by a lithium battery, and features a day-

of-week register and leap year correction.

6.6 AN OVERVIEW OF FINGERSCAN TECHNOLOGIES

The fundamental limiting factor for Finger-scan technology has been the process

by which the devices capture an image of the finger. The most common technologies

are: Optical, Silicon, Ultrasound and Touchless. Optical Scanner relies on an image of

ridges and valleys of the print. The process, referred to as Frustrated Total Internal

Reflection, a form of spectroscopy, essentially takes a picture of finger. Silicon or

Capacitance Fingerprint scanners often great potential because if utilizes higher image

quality than optical surface contamination found on the finger. Thermal Fingerprint

scanners uses infrared to sense the temperature differences between the ridges and

valleys of the finger to create a fingerprint image. Ultrasonic Fingerprint scanner scans

the finger ultrasonically, using high frequency sound waves, to capture an image of the

finger.

6.7 CAPACITANCE SCANNER

Capacitive fingerprint scanners generate an image of the ridges and furrows that

make up a fingerprint. This type of scanner senses the print using electric current.



CAPACITANCE SCANNER

The diagram shown a simple capacitive sensor, The sensor is made up of one or

more semiconductor chips containing an array of tiny cells. Each cell includes two

conductor plates, covered with an insulating layer. The cells are tiny – smaller than the

width of one ridge on a finger.

The sensor is connected to an integrator, an electric circuit built around an

inverting operation amplifier. The inverting amplifier is a complex semiconductor

device, made of a number of transistors, resistors and capacitors.

Like any amplifier – an inverting amplifier alters one current based on

flucturations in another current. Specifically, the inverting amplifier has the inverting

terminal and the non/inverting terminal. In this case the non-inverting terminal is

connected to ground, and the inverting terminal is connected to a reference voltage

supply and a feed back loop. The feed back loop, which is also connected to the

amplifier output, includes the two conductor plates.



The two conductor plates form a basic capacitor, an electric component that

can store up charge. The surface of the finger acts as a third capacitor plate, separated

by the insulating layers in the cell structure and, in the case of the fingerprint valleys, a

pocket of air. Varying the distance between the capacitor plates (by mainly the finger

closer or farther away from the conducting plates) changes the total capacitance (ability

to store charge) of the capacitor. Because of this quality, the capacitor in a cell under a

ridge will have a greater capacitance than the capacitor in a cell under a valley.

To scan the finger, the processor first closes the reset switch for each cell,

which shorts each amplifier input and output to balance the integrator circuit. When the

switch is opened again, and the processor applies a fixed charge to the integrator circuit,

the capacitors charge up. The capacitance of the feedback loop’s capacitor affects the

voltage at the amplifier’s input, which affects the amplifier’s output. Since the distance

to the finger alters capacitance, a finger ridge will result in a different voltage output

than a finger valley.

The scanner processor reads this voltage output and determines whether it is

characteristic of a ridge or an valley. By reading very cell in the sensor array, the

processor can put together an overall picture of the fingerprint, similar to the image

captured by an optical scanner.

The main advantage of a capacitive scanner is that it requires a real fingerprint

– type shape rather than the pattern of light and dark that make up the visual impression

of a fingerprint. This makes the system harder to trick. Additionally since they use a

semiconductor chip rather than a CCD (charge coupled device) unit as in case of Optical

scanner, capacitive scanners tend to be more compact than Optical devices.



6.8 ADVANTAGES OF FINGERPRINT SCANNERS

Compared to the other biometric authentication technologies, fingerprint

scanners are:

The most widely available device.

Relatively low cost

Small size (easily integrated into keyboards) and

Easy to integrate

Fingerprint verification may be a good choice for in-house systems where

adequate explanation and training can be provided to users and where the system is

operated within a controlled environment.

6.9 DISADVANTAGES

Fingerprint verification can suffer under large-scale usage. In a large

population, poorly trained users cause higher usage errors and hence higher instances of

false rejection. Also, the user interface (scanning module) can become damaged or

dirty by large-scale usage.



7. FUTURE APPLICATIONS

There are many concerning potential fingerprint applications, some popular

examples being:

7.1 ATM MACHINE USE

Most of the leading banks have been experimenting with biometrics of ATM

Machines use and as general means of combining card fraud. It is estimated that lesser

due to identity fraud in welfare disbursements, credit card transactions, cellular

telephone calls, and ATM withdrawals total over $ 6 billion every year. At present an

ATM identifier a person as a client after the person inserts an ATM card into the

machine and enters a personal identification number (PIN). This method of

identification has its drawbacks. According to researchers, about one-fourth of bank

customers apparently write their PIN on their ATM card, thus defeating the protection

offered by a PIN when an ATM card is stolen.

7.2 INTERNET TRANSACTIONS

Security for information systems and computer networks is another important

area for fingerprint applications. Access to databases by means of remote login is

another application. Some experts anticipate that more and more information systems,

computer networks, and world wide web sites will use fingerprint identification

techniques to control access and for other security purposes.



7.3 PERSONAL TRANSPORTATION

Several leading automobile manufacturers are exploring the use for fingerprint

identification to enable an authorized driver to enter and start a car without using a key.

7.4 USE IN PUBLIC SECTOR

Various government agencies have considered using biometric fingerprint

identification. In benefits distribution programs such as welfare disbursement,

fingerprint identification techniques could bring about substantial savings by deterring

the same person from filing multiple claims. Fingerprint based voter registration can be

used to verify identity at the polls to prevent fraudulent voting. In

Academics/certifications it can be used to verify person’s identity prior to taking an

exam.



8. CONCLUSION

Biometric fingerprint identification has many usability advantages over

traditional systems such as passwords. Specifically, users can never lose their

fingerprints, and the fingerprint is difficult to steal or forge. The intrinsic bit strength of

a fingerprint is quite good when compared to conventional passwords. Finger scanners

are getting smaller, cheaper, and more accurate, and can be used in mobile gadgets

without sprucing up the size, cost, and power consumption. By using this technology

theft can be prevented and can also eliminate fraudulent transactions. Mobile

manufacturers and wireless operators are incorporating voice and fingerprint scanning

techniques in their devices. Fingerprint is a very strong desktop solution, and it is

anticipated that the desktop will become a device for biometric revenue derived from

product sales and transactional authentication. Most middleware solutions leverage a

variety of fingerprint solutions for desktop authentication.

Fingerprint is a proven technology capable of high levels of accuracy. Strong

fingerprint solutions are capable of processing thousands of users without allowing a

false match, and can verify nearly 100% of users with one or two placements of a

finger. Because of this, many fingerprint technologies can be deployed in application

where either security or convenience is the primary driver. Reduced size and power

requirements, along with fingerprint’s resistance to environmental changes such as

background light and temperature, allow the technology to be deployed in a range of

logical and physical access environments. Fingerprint acquisition devices have grown

quite small sensors slightly thicker than a coin, and smaller than 1.5 cm x 1.5 cm, are

capable of acquiring and processing images. Thus fingerprint has emerged as a highly

distinctive identifier, and classification, analysis and study of fingerprints has existed

for decades.



9. REFERENCES

1. Electronics for you – June 2002

2. RSA Security’s official guide to CRYPTOGRAPHY BY Steve Burnett and

Stephen Paine.

3. Infokairali – December 2001.

4. http://www. biometricgroup.com.

5. Encarta Encyclopedia 2002.

6. http://www. howstuffworks.com.

7. http: //www. BiometricID.org.



ABSTRACT

Identification of individuals is a very basic societal requirement. Electronic

verification of a person’s identity is of great importance as more interactions take

place electronically. Biometric fingerprint identification is a technique used to

change the physical attribute of a person ie; his finger print into electronic

processes. Until recently electronic verification was based on something the

person had in their possession like a password. But the problem is that these

forms aren’t very secure because passwords can be forgotten or taken away. In

biometric finger print identification a scanner is used to get the image of the

finger. When a user places his or her finger on the terminals of scanner the

image is electronically read, analysed and compared with a previously recorded

image of the same finger, which has been stored in finger scan data base.

Finger print is a proven technology capable of high levels of accuracy.



ACKNOWLEDGEMENT

I express my sincere gratitude to Dr.Nambissan, Prof. & Head,

Department of Electrical and Electronics Engineering, MES College of

Engineering, Kuttippuram, for his cooperation and encouragement.

I would also like to thank my seminar guide Mrs. Renuka.T.K.

(Lecturer, Department of EEE), Asst. Prof. Gylson Thomas. (Staff in-charge,

Department of EEE) for their invaluable advice and wholehearted cooperation

without which this seminar would not have seen the light of day.

Gracious gratitude to all the faculty of the department of EEE &

friends for their valuable advice and encouragement.



CONTENTS

1. INTRODUCTION 1

2. IDENTIFICATION AND VERIFICATION SYSTEMS 2

3. BIOMETRIC SYSTEMS AND DEVICES 3

4. BIOMETRIC ACCURACY 4

5. FINGERPRINT VERIFICATION 5

6. FINGERSCAN 6

6.1 THE TECHNOLOGY BEHIND FINGERSCAN 6

6.2 THE ALGORITHMS 7

6.3 SYSTEM FUNCTIONS 8

6.4 MANAGEMENT CONTROL 10

6.5 SECURITY 11

6.6 AN OVERVIEW OF FINGERSCAN TECHNOLOGIES 13

6.7 CAPACITANCE SCANNER 13

6.8 ADVANTAGES OF FINGERPRINT SCANNERS 16

6.9 DISADVANTAGES 16

7. FUTURE APPLICATIONS 17

8. CONCLUSION 19

9. REFERENCES 20


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