Cell phones are already prime targets for theft. The increasing functionality of cell phones is making them even more attractive. With the increase of cell phone functionality including personal digital assistance, banking, e-commerce, remote work, internet access and entertainment, more and more confidential data is stored on these devices. What is protecting this confidential data stored on cell phones? Studies have shown that even though most of the cell phone users are aware of the PIN security feature more than 50% of them are not using it either because of the lack of confidence in it or because of the inconvenience. A large majority of those users believes that an alternative approach to security would be a good idea.biometrics, security, fingerprint, face recognition, cell phones

Adrian POCOVNICU

English

Research Papers in Economics

Informatica Economică vol. 13, no. 1/2009  57
Biometric Security for Cell Phones 
 
Adrian POCOVNICU 
Academy of Economic Studies, Bucharest, Romania 
pocovnicu@gmail.com 
 
Cell phones are already prime targets for theft. The increasing functionality of cell phones is 
making them even more attractive. With the increase of cell phone functionality including 
personal digital assistance, banking, e-commerce, remote work, internet access and enter-
tainment, more and more confidential data is stored on these devices. What is protecting this 
confidential data stored on cell phones? Studies have shown that even though most of the cell 
phone users are aware of the PIN security feature more than 50% of them are not using it ei-
ther because of the lack of confidence in it or because of the inconvenience. A large majority 
of those users believes that an alternative approach to security would be a good idea.  
Keywords: biometrics, security, fingerprint, face recognition, cell phones. 
 
Introduction to Biometrics 
The etymology of the word biometrics 
comes from the ancient Greek words: “bios” 
– life and “metros” – measure. 
Biometrics is the science and technology 
used to uniquely identify individuals based 
on their physical, chemical or behavioral 
traits. Biometric systems are assuming that 
many of the physical, chemical and beha-
vioral human traits are distinctive to each in-
dividual, that they can be accurately captured 
using sensors and devices and that they can 
be represented in a format appropriate for au-
tomatic decision making in regards with the 
identity of the individual. 
Biometric security differentiate from the 
classic security methods because it identifies 
an individual based on what he is rather than 
on what he possesses or what he remembers. 
The advantage of biometric systems over tra-
ditional security methods is that they cannot 
be stolen or shared. 
Traditional security practices often involve 
the use of two authentication methods: pos-
session based and knowledge based. Know-
ledge based authentication requires that the 
users remember a user name and password or 
PIN numbers or answers to security ques-
tions. Possession based can use radio fre-
quency IDs, Smart Cards, Interactive Tokens 
etc. Possession based authentication has the 
same usability issue as the knowledge based 
authentication, if the object used for authen-
tication is forgotten at home, in the hotel 
room, in the car etc the authentication cannot 
be performed.  
Biometric security systems are using:  
‐  Physical human identifiers like fingerprint, 
face, iris, retina, DNA, hand geometry and 
vein geometry 
‐  Behavioral identifiers like speech, signa-
ture, and keystroke timing  
‐  Chemical identifiers like odor and body 
heat. 
Biometric systems are used for two purposes. 
One is to verify that the user is genuine by 
comparing the acquired biometric trait with 
the one stored for that user. The other pur-
pose the biometrics are used is to identify a 
user in which case the acquired biometric 
trait is compared with a collection of the 
same traits from multiple users. 
 
2. Elements of a biometric system 
A generic biometric system is comprised of 
the following units: 
‐  A sensor unit that represents the interface 
between the user and the machine. This is the 
point where the biometric trait is acquired; 
‐  A processing unit where the acquired bio-
metric is sampled, segmented and features 
are being extracted. It also includes quality 
assurance to determine if the quality of the 
biometric is good enough to be used further 
in the process. If the quality of the acquired 
biometric is poor, the user may be asked to 
present the biometric again; 
‐  A database unit where all the enrolled 
1 Informatica Economică vol. 13, no. 1/2009  58
biometric templates are being stored and 
where the templates are being retrieved from 
in the authentication process; 
‐  A matching unit that compares the newly 
acquired biometric template with the tem-
plates stored in the database and based on 
decision rules determines either if the pre-
sented biometric is a genuine/impostor or if 
the user is identified or not. 
The following image shows the enrolment 
and recognition process flow in a biometric 
system.
 
 
Fig. 1. Biometric Systems Classes 
 
 
Fig. 2. Enrollment and Recognition in a Biometric System 
 
3. Biometrics characteristics 
Choosing between different biometrics is not 
an easy task. Each biometric has its own pros 
and cons and the selection of a biometric for 
an application should depend not only on its 
matching performance but also on other fac-
tors that determine if a biometric treat is suit-
able for the application or not. The following 
biometric characteristics should be evaluated 
in the selection process of a biometric sys-
tem: 
‐  Universality – each person that is using the 
biometric system should possess the biome-
tric trait Informatica Economică vol. 13, no. 1/2009  59
‐  Uniqueness – measures how well the bio-
metric trait separates one individual from 
another 
‐  Permanence – measures how well a biome-
tric trait resists aging 
‐  Collectability – ease of acquisition of the 
biometric trait without causing inconve-
nience to the user 
‐  Performance – accuracy, speed, robustness 
of technology used 
‐  Acceptability – degree of approval of the 
biometric technology by the users 
‐  Circumvention – ease of use of an imita-
tion of the biometric treat. 
No biometric is perfect. None of the biome-
trics would satisfy 100% the characteristics 
listed above. Depending on the application, 
decision makers should review the characte-
ristics and determine which ones are a must 
for their organization. 
 
Table 1. Comparison of various biometric technologies [2] 
Biome­
trics    
Universali­
ty   
Unique­
ness   
Perma­
nence   
Collectabili­
ty   
Perfor­
mance  
Acceptabili­
ty   
Circumven­
tion 
Face  HIGH LOW  MEDIUM HIGH LOW HIGH  LOW
Finger­
print 
MEDIUM  HIGH  HIGH MEDIUM HIGH MEDIUM  HIGH
Hand geo­
metry 
MEDIUM  MEDIUM  MEDIUM HIGH MEDIUM MEDIUM  MEDIUM
Keystrokes  LOW LOW  LOW MEDIUM LOW MEDIUM  MEDIUM
Hand veins  MEDIUM  MEDIUM  MEDIUM MEDIUM MEDIUM MEDIUM  HIGH
Iris  HIGH HIGH  HIGH MEDIUM HIGH LOW  HIGH
Retinal 
scan 
HIGH HIGH  MEDIUM LOW HIGH LOW  HIGH
Signature  LOW LOW  LOW HIGH LOW HIGH  LOW
Voice  MEDIUM  LOW  LOW MEDIUM LOW HIGH  LOW
Facial 
thermo­
graph 
HIGH HIGH  LOW HIGH MEDIUM HIGH  HIGH
Odor  HIGH HIGH  HIGH LOW LOW MEDIUM  LOW
DNA  HIGH HIGH  HIGH LOW HIGH LOW  LOW
Gait  MEDIUM  LOW  LOW HIGH LOW HIGH  MEDIUM
Ear Canal  MEDIUM  MEDIUM  HIGH MEDIUM MEDIUM HIGH  MEDIUM
 
4. Biometric Systems Benefits 
A biometrics security system offers the fol-
lowing benefits: 
It doesn’t require cooperation. Some bio-
metric systems as face recognition, gait rec-
ognition, odor recognition or face thermo-
graph don’t require that the user cooperates 
so that the biometric is collected. Biometric 
systems prove useful in train stations, air-
ports, stadiums etc., to identify wanted fe-
lons. 
It guarantees physical location of the user. 
It can be determined with certainty that the 
user was that the point where the biometric 
was collected at the time when the biometric 
was collected. 
It has high-throughput. When there is a 
need to identify a person from a large popu-
lation, automatic biometric identification 
may be the only efficient solution. 
The biometric trait is unforgettable. Un-
like the classic passwords that need to be re-
membered, biometric traits cannot be forgot-
ten because they represent something that the 
user is: physically, behaviorally or chemical-
ly. 
The biometric trait cannot be lost. Unlike 
authentication tokens, id cards or passwords 
written on a piece of paper, biometric traits 
cannot be lost.  
It cannot be shared.  Due to their nature 
biometric traits cannot be shared between us-
ers. This ensures that the user that logs in the 
system is the actual user and not a colleague Informatica Economică vol. 13, no. 1/2009  60
that is trying to help. 
It is cost efficient. Sure there will be an up-
front cost with the installation of the system 
and with user’s education but in the long run 
it proves cost efficient due to the benefits 
listed above. It cannot be shared and it guar-
antees physical location; this way no em-
ployee can help-out a colleague that is late by 
punching-in in the time system on his behalf. 
And it cannot be lost or forgotten; this way 
costs of reissuing new identification tokens 
are reduced, the desktop support time is re-
duced because the need of resetting pass-
words will be less, if any, and the down-time 
of the employees because they’ve got locked 
out from the systems is also reduced.  
 Fig. 3. Examples of Biometric Traits [1] 
 
 
It can provide emergency identification. In 
those cases when a person cannot identify it-
self, using a biometric system may be the on-
ly way to find his identity. 
It prevents identity theft. In the most cases 
of identity theft, the impostor used victim’s 
name and personal identification number to 
create credit card accounts and use those in 
his behalf. Using biometric security systems 
makes it practically impossible for impostors 
to pretend they are somebody else.  
It is appealing. Most people find biometric 
systems appealing because of the ease of use 
and because it is impressive how a door can 
be opened by just a swipe of a finger. 
 
5.  Cell Phone Devices 
In October 13, 1983 first commercial cell 
phone call was made. The phone cost nearly 
$4000 and it was weighting about 2.5 
pounds. It was a Motorola DynaTAC and on-
ly very wealthy people could afford it. Since 
then cell phones have benefited of an amaz-
ing evolution. 
 
Fig. 4. Motorola DynaTAC – First Commer-
cial Cell Phone [5] 
 
Between 1992 and 2002 the main develop-
ment goal of cell phones manufacturers was 
to reduce the size of the device. Around 2002 
the phones were so small that that it wasn’t 
practical from ease of use point of view to 
shrink them even more. 
This was the time when development started 
focusing adding other features to the phone 
beside voice and SMS texting. The initial 
black and white displayed started being re-
placed by color displays and screen resolu-
tion became higher and higher. The new fea-
tures that cell phones users started to benefit 
of are: multimedia, internet, email and per-
sonal organizer. 
Today’s cell phones can be classified in the 
following categories: 
‐  Entry level cell phone 
‐  Smartphone 
‐  PDA Informatica Economică vol. 13, no. 1/2009  61
‐  Connected music players 
Entry level cell phones are optimized for 
voice communication. Entry level cell phone 
are sold today in both developed markets and 
emerging economies. The functionality of 
such phones has not changed in the past dec-
ade but the prices have dropped dramatically 
due to higher volume production and fewer 
materials required for production (figure 9). 
These types of phones are using proprietary 
operating systems, have no or limited multi-
tasking capabilities for applications.  
Third party developers don’t have access to 
the operating system and the only way they 
can extend the capabilities is by using java 
programming.  
 
  
Fig. 5. Nokia 2135 [6] 
 
Fig. 6. Nokia 9300 
Smartphone [7] 
 
A smartphone is a cell phone with advanced 
features like internet and email capabilities. 
Smartphones often use an open operating 
which allows applications development ei-
ther by the manufacturer, service provider or 
third parties. 
PDA Phones are an evolution of PDAs. 
They use operating systems like Microsoft 
Windows Mobile, Palm OS, Symbian etc. 
and they include office applications, task 
scheduling and personal organizer. The dif-
ferences between PDA phones and Smart-
phones are becoming smaller but the PDAs 
tend to keep the original shape. 
 
 
Fig. 9. Block diagram of a voice-optimized 
mobile phone hardware platform.[10] 
 
Music Player Phones are portable music 
player phones. They may have integrated in-
ternet connectivity (3G), integrated web 
browser. A very popular example of a device 
within this category is Apple’s iPhone. 
 
6. Biometrics and Cell Phones 
Biometric systems can be integrated with cell 
phones in two ways: As a biometric collect-
ing device or as a stand-alone system to pro-
tect unauthorized use of the cell phone. In the 
first case cell phones are collecting the bio-
metric and then they are passing it via inter-
net or via voice communication to a remote 
location where it is processed and matched. 
This proves useful for remote transactions 
when the identity of the caller has to be prov-
en. As an example, the user calls his bank to 
make a transaction, he is going to introduce 
himself as John Smith and in order to verify 
 
Fig. 7. HTC Touch 
Diamond 2 [8] 
 
Fig. 8. iPhone [9] 
 Informatica Economică vol. 13, no. 1/2009  62
his identity he is asked to recite a passphrase. 
The voice recording is then processed and 
compared with the sample that was collected 
when the user enrolled in the system. Face, 
fingerprint, signature or key stroke are other 
biometric traits that today’s cell phones have 
the capabilities to collect and transfer them to 
a remote location. 
The other implementation of biometric sys-
tems on cell phones is that the entire biome-
tric system resides on the cell phone and it 
serves the purpose of preventing unautho-
rized access to cell phone’s functions and da-
ta. 
Biometric systems can replace the annoying 
PIN security and with a swipe of a finger the 
phone can be unlocked and used. Today’s 
implementations of biometric systems on cell 
phones include fingerprint recognition, voice 
recognition, face recognition, signature rec-
ognition and keystroke recognition. 
Fingerprint. AuthenTec is a world leader in 
providing fingerprint recognition biometric 
systems. 
AuthenTec’s suite of technologies includes: 
TruePrint®, TouchStone™, TrueMatch™, 
TrueFinger™, TrueNav™, TrueYou™.  
TruePrint® is used to capture the fingerprint 
image from the live layer of skin beneath the 
surface. This has reduces the risk of not ac-
cepting a fingerprint because the skin surface 
has worn-out. TouchStone™ is a technology 
to create waterproof sensors. 
TrueFinger™ is a technology that ensures 
that only real fingerprints are being read. 
TrueNav™ is a technology that tracks the 
motion of the finger on the sensor and it is 
translated in the move of a cursor on the 
screen. TrueYou™ technology allows start-
ing different applications depending on the 
finger that is swiped [11]. 
Pantech was the first manufacturer to put a 
fingerprint scanning technology on its GI 100 
mobile phone.  
Lenovo have integrated fingerprint security 
in its P960 phone to protect the sensitive data 
such as VIP recordings, address book infor-
mation, call history, text messages etc. Fujit-
su launched first waterproof fingerprint-
enabled mobile phone using TouchStone™ 
technology from AuthenTec.  
Face recognition. ClassifEye and Omron are 
between the companies that have developed 
face recognition technology for use as securi-
ty system in camera-enabled cell phones. The 
advantage of this technology is that it doesn’t 
require any additional hardware because 
cameras already exist in most of the phones. 
The minimum required camera resolution for 
the system to work is 100,000 pixels [13]. 
 
 
Fig. 10. Pantech GI 100 Scanning Method 
and Capture Fail Icons [12] 
 
Sharp has integrated face recognition soft-
ware in its mobile phones. To unlock the de-
vice it has to match user’s face captured by 
live camera against a saved portrait. 
 
Fig. 11. Face Recognition Vectors [1] 
 
Dynamic Signature Analysis relies on the 
manner in which a signature is written rather Informatica Economică vol. 13, no. 1/2009  63
than the physical appearance of the signature. 
Using a PDA users sign in their name mul-
tiple times. Features like pressure, direction 
or velocity are recorded during enrollment
 
[14]. 
 
Conclusions 
Biometric systems are offering a more con-
venient way to secure private information 
stored on mobile phone. Biometrics systems 
are also adding security to remote transac-
tions initiated using a phone.  
Voice recognition, face recognition, signa-
ture recognition or keystroke recognition are 
biometric security systems that can be im-
plemented on most of the mobile phones 
since they don’t require any additional hard-
ware.  
Fingerprint recognition systems require addi-
tional hardware, a fingerprint scanner, but 
that sensor has more technologies built in it, 
like screen cursor movement or having favo-
rite applications starting at a touch of a fin-
ger, that is making the devices which have a 
fingerprint sensor very appealing. 
Biometric security systems for cell phone are 
not only making cell phones more secure but 
they are also are making cell phones use eas-
ier and even more entertaining. 
 
References 
[1] A. K. Jain, P. Flynn, A. ROSS, Handbook 
of Biometrics, Springer, USA, 2008. 
[2] A. K. Jain, A. Ross, S. Prabhakar, “An in-
troduction to biometric recognition”, 
IEEE Transactions on Circuits and Sys-
tems for Video Technology, Vol. 14, No. 
1, pp. 4-20, January 2004.  
[3] K. Revett, PhD, Behavioral Biometric A 
Remote Access Approach, Wiley, UK, 
2008. 
[4] S. Holtmanns, V. Niemi, P. Ginzboorg, P. 
Laitinen, N. Asokan, Cellular Authentica-
tion For Mobile And Internet Services, 
Wiley, UK, 2008. 
[5]  Motorola DynaTAC 8000X – World’s 
First Mobile Phone [Online]. Available:   
http://www.tech-fresh.net/motorola-
dynatac-8000x-worlds-first-mobile-phone 
[6]  Nokia USA – Nokia 2135 [Online]. 
Available:  http://www.nokiausa.com/ 
link?cid=PLAIN_TEXT_842095 
[7] Nokia USA – Nokia 9300 Smartphone – 
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9300-smartphone 
[8] HTC – Products –HTC Touch Diamond2 
[Online]. Available: http://www.htc.com/ 
www/product/touchdiamond2/overview.h
tml 
[9] Apple–iPhone – Gallery [Online]. Avail-
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[10] M. Sauter, Beyond 3G – Bringing Net-
works, Terminals and the Web Together, 
Wiley, UK, 2009. 
[11] Authentec | Technology [Online]. Avail-
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[12]  Global – Pantech – Manual [Online]. 
Available:  http://global.pantech.com/fup 
/support/manual/60_30232759.pdf 
[13]  Technology News – PCWorld’s Tech-
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news/Mar0120 05id119850.htm 
[14]  Emerging Biometric Technologies – 
Crime, Law Enforcements and Correc-
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business.com/crime-law/law-biometrics-
fingerprinting/1054 6671-1.html
 
Adrian POCOVNICU is a PhD Candidate at Academy of Economic Studies. 
His main research areas are: Multimedia Databases, Information Retrieval, 
Multimedia Compression Algorithms and Data Integration. He is a Data Inte-
gration Consultant for ISA Consulting, USA. 

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