Every homo has different traits that distinct each individual from the other. These traits can be categorized as behavioral or physiological depending on the nature of the characteristic. Biometricss are methods that can place or verify the designation of a individual based on those features. The most normally used biometries are fingerprints, face and manus geometry, flag and signature.

Security systems are utilizing biometric methods for secure hallmark for many old ages. Of class biometries are normally used merely in a little graduated table, like high security installings. But now advances in engineering can supply new ways of implementing biometric-based solutions in a larger graduated table. For illustration some industries have integrated fingerprint scanners on their nomadic computing machines.

There are two manners of operation on biometric systems. The confirmation manner that verifies the individuality of a specific individual and the designation manner that tries to place a individual through the full biometries database. Of class biometries systems for unafraid hallmark are runing on confirmation manner.

The public presentation and the efficiency of a system that uses biometries for designation, is tested and evaluated by multiple surveies. The features that are more efficaciously used for unafraid hallmark are fingerprints and iris scanning.

The usage of biometries systems has introduced many advantages. The most of import are the betterment in security, the reduced cost and the significantly reduced duplicity. The disadvantages are the deficiency of common criterions in industry, the temporary inefficiency of biometries to implement on a big scale footing and most of all the denial of the common people to encompass biometries for designation and confirmation. The latter is a big issue that needs to be solved in order to implement biometries in a larger graduated table.


There are three ways to authenticate the individuality of a user [ Pfleeger and Pfleeger, 2007 ] .

  • Something you know
  • Something you have
  • Something you are

The? something you know? attribute refers to something that the user has to retrieve to turn out his individuality. These can be watchwords, passphrases or PIN Numberss. The most common manner is the usage of a watchword. The user has to supply the right watchword to derive entree. Passphrases are normally used for secondary degree of hallmark. For illustration web sites use passphrases to place the user if the user has lost or forgot the chief watchword. PIN Numberss normally used combined with an individuality or a smart card. For illustration an ATM of a bank needs both the smartcard and the PIN figure to authenticate the user.

The? something you have? attribute refers to something that the user possesses. As a regulation, a item is registered to a user in order to authenticate his individuality. There are two types of items: the storage and the dynamic items. The storage items are normally smartcards or usb devices. To forestall unauthorised entree with a stolen item, items are normally combined with a watchword such as the ATM illustration of the old paragraph. The dynamic items have many signifiers that include smartcards and usb devices. The difference is that dynamic items provide a one clip codification that can ne’er be used once more. That is why they are more unafraid than storage items.

Finally the? something you are? attribute refers to a mensurable feature of a individual. These features are called biometries, and they can be fingerprints, manus geometry etc. First the biometries of a peculiar user have to be measured and stored. Then, when a user needs hallmark, the freshly measured biometries have to be compared with the stored 1s. If they match the hallmark is complete. The biometries are presented in more item in the following chapter [ Reid, 2004 ] .

There is besides another manner, which is related to where you are. For illustration the ability to entree a specific terminal gives the mandate to the user. But this does non depend on the user himself but to other factors that are non relevant to his individuality. Of class this can be combined with another hallmark factor in order to do hallmark more unafraid [ Hebbes, 2009 ] .


The two chief classs of biometries are the physiological and the behavioral features. The physiological features are related to the form and the signifier of a individual? s organic structure. The most common are fingerprints, flag and retina, face and manus geometry. The behavioral features are related to a individual? s behavior. Those features include signature, pace, voice and keystroke pattern [ Braghin, 2000 ] and [ Liu and Silverman, 2001 ] .

Following are presented the biometric features that are used for hallmark and confirmation [ Hong, Jain and Pankanti, 2000 ] .


Fingerprints have been used for designation for many old ages. Every individual? s fingertip has a distinguishable form of furrows and ridges. These are so alone that even indistinguishable twins have different fingerprints. Progresss in engineering make fingerprint based hallmark devices more low-cost. Nowadays assorted devices include fingerprint hallmark devices and their figure is expected to increase in the undermentioned old ages. For illustration, a new coevals of consumer portable computing machines has incorporated fingerprint hallmark.

Hand Geometry

Hand geometry includes several measurings of a individual? s manus. These are the form of the manus and the breadths and lengths of the fingers. The biometric systems that use that engineering are widely used. The ground they are so widespread is because this technique is really simple to implement, with low cost and really easy to utilize. Environmental factors are non impacting the technique? s truth. The job is that manus characteristics can alter through the lifetime of a individual, particularly during childhood. Another disadvantage is that manus geometry biometric devices have to be big because of the physical size of the manus.


Biometricss based on facial features are likely the most common techniques for the designation of a individual. They are based on features such as nose, eyes, lips, mentum and nose. It is non merely the form of them but the overall analysis of their comparative place in the face. The job of the facial designation is that it is really hard to place a individual utilizing two different exposures particularly when they have different shot angles. To transgress that obstruction assorted limitations are imposed in the image hiting procedure in order to do a individual? s image more typical.

Facial Thermogram

Facial thermogram is the image that is produced by the face of a individual utilizing an infrared camera. Every human face creates a facial signature when heat goes through the tissues of the tegument. This image is alone to each individual and it is non susceptible to camouflages or even fictile surgery. Although it is alone it depends on assorted factors such as the temperature of the organic structure or the province of the emotions of a individual. Of class the chief advantage is that an infrared image can be taken even on a low visible radiation environment.


In the human oculus, under the retinal surface there are venas that create a alone form. Using beams of low strength it is possible to capture an image of the retina. In order to capture this image, a individual has to look on a individual topographic point. The chief disadvantage of this engineering is that the equipment that is needed for the scanning is really expensive. Despite that it is widely used in installings that require high security.


Iris is the colored portion of the oculus. It has a construction really complex and it is alone to each individual even on twins. It is really hard to anneal the scan and it can observe even contact lenses. The equipment is still expensive but new developed equipment is expected to be cheaper and friendlier to the user.


The manner of authorship is alone to each individual. On the other manus two signatures by the same individual can be different and they depend on the individual? s emotional and physical province. The systems that are based on signature designation are accurate plenty but are non equal for big scale execution. There are two ways of designation. The inactive, that uses the geometric properties of the signature and the dynamic, that uses geometric and properties such as force per unit area, acceleration, flight and speed.


Speech designation is normally accurate but is besides non suited for big scale designation. There are two ways of designation, the text based and the text independent. The text based needs a predetermine phrase in order to place a individual. Conversely the text independent confirmation doesn? Ts need a specific phrase. That? s why it is more accurate, more difficult to lead on but more hard to implement.

Apart from the old features there is besides another group of biometric features that is non so normally used. Following, are presented the staying features [ Jain, Ross and Prabhakar, 2004 ] .

Deoxyribonucleic acid

Deoxyribonucleic acid is alone to each individual with the exclusion of the indistinguishable twins. It is used for designation largely in forensics. There are three factors that prohibit Deoxyribonucleic acid to be used in other applications. First, it is easy to obtain DNA pieces from a individual and utilize them for duplicity. Second, the Deoxyribonucleic acid analysis needs particular engineering that requires clip. Finally, there are besides privacy issues about the individual? s information that carries a Deoxyribonucleic acid piece.


Ear acknowledgment based on the construction and the form of the ear. It measures several points from the cardinal point of the ear. It is non expected to be really accurate in designation.


It is a behavioral biometric and it is based on the manner that a individual walks. It uses footage from a picture sequence and measures the motions from assorted parts of a individual? s organic structure during walking. The designation utilizing pace is sufficient merely for low security intents.

Olfactory property

Each object has an olfactory property that is distinguishable and each olfactory property has a alone chemical composing. Any organic structure ( human or animate being ) emits a specific olfactory property. A group of detectors can feel certain chemical compounds in order to place a individual. But it is non certain that it gives dependable consequences when deodourants are used.


Keystoke kineticss is besides a behavioral biometric. Each individual uses the keyboard in its ain different manner. It is non alone but is sufficient for low security designation.


A biometric system collects the biometric information from a individual and so compares them to the stored informations from the database. There are two different manners on the operation of a biometric system: the confirmation and the designation manner [ Jain, Ross and Prabhakar, 2004 ] .

Confirmation manner: the system captures the biometric information from the individual and so they are compared to the stored informations of the specific individual. For illustration, a individual is seeking to derive entree to a system claiming his individuality by a card, a user name and watchword etc. and so the system compares the freshly acquired biometric informations of the individual with the stored informations of the individual with this individuality. Verification is aimed to forestall the usage of the same individuality by several individuals.

Designation manner: the system captures the biometric information from a individual and so it compares them with all the stored informations of the database. In this state of affairs, the individual is non claiming a specific individuality and the comparing will be successful or non successful if the individual? s biometric informations is non in the database. Designation is aimed to avoid the usage of the assorted individualities by assorted individuals.

The system that is designed for secure hallmark has to run in confirmation manner. So, to authenticate a user, it is necessary to infix the biometric informations of all the users to the systems database. A secure hallmark system in order to work decently has to finish two phases: the registration phase and the designation phase [ Braghin, 2000 ] .

In the registration phase the biometric informations are inserted to the systems database. This map is performed merely one clip. This phase consists by three undertakings: scanning, digital representation and recording. First the individual is scanned and the biometric features are captured, so they are converted to digital informations and eventually these informations are stored on the systems database.

In the designation phase the system identifies the individuals when it is asked to. This map is performed multiple times at the entree point. This phase besides consists of three undertakings: scanning, digital representation and matching. As in the registration phase the individual is scanned and the characteristic are converted to digital informations. Then these informations are compared with the informations from the systems database. If they match the petition is granted, and if they don? T, the petition is rejected.

A biometric hallmark system has to be consisted by four chief constituents: [ Rejman-Greene, 2002 ]

  • A detector that is able to capture the biometric features
  • An algorithm that is able to compare the input informations with the systems stored informations
  • An rating faculty that is able to make up one’s mind if the consequence of the comparing is accepted or non
  • A on the job model for the application and the secondary procedures ( both package and hardware )

The system that uses merely one biometric feature by a individual beginning is called unimodal. To better the public presentation of such a system another sort of system is developed which is called multimodal. Multimodal systems combine informations from multiple beginnings. There are four basic types of multimodal systems: [ Jain and Ross, 2004 ]

  • Use of multiple detectors to garner informations for the same characteristic
  • A system that has merely one detector but the informations are processed by multiple algorithms
  • Use multiple units to capture the same characteristic ( such as different fingerprint of the same individual )
  • A system that uses multiple features of a individual.

In that manner biometric systems improve public presentation, addition people coverage and cut down duplicity.


In order to compare and measure the public presentation of the assorted biometric features, there are a figure of issues to be considered. First, each feature has to follow with the undermentioned demands: [ Jain, Ross and Prabhakar, 2004 ] .

  • Universality: when each individual possess the specific feature
  • Peculiarity: when two individual do non portion the same characteristic
  • Permanence: when a certain characteristic can non be altered or changed
  • Collectability: when a characteristic can be easy measured
  • For the design of a biometry system that is able to execute hallmark, there are three more issues to be considered [ Hong, Jain and Pankanti, 2000 ] .

  • Performance: refers to the velocity, truth and hardiness of the system and besides the factors that affects the operation of the system.
  • Acceptability: refers to the extension of the credence of a specific biometric system in the lives of the common people.
  • Circumvention: refers to how easy the system can be fooled.

The following tabular array shows the public presentation and the comparing between the different biometric features. ( where H: High, M: Medium, L: Low )

In order to mensurate the truth of biometries for an hallmark system there are assorted statistical measurings. The most common are the False Acceptance Rate ( FAR ) and the False Rejection Rate ( FRR ) [ Crosbie, 2005 ] .

  • False Acceptance Rate ( FAR ) : the chance to authorise a individual with stolen individuality
  • False Rejection Rate ( FRR ) : the chance to reject a individual with valid individuality

These measurings do non mensurate merely the biometric feature but the system that uses the specific feature in conformity with it. Assorted undertakings and surveies evaluate systems that use merely a specific feature for hallmark. But by and large the biometries that perform better in footings of False Acceptance Rate ( FAR ) and the False Rejection Rate ( FRR ) are the iris scanning and the fingerprints [ Reid, 2004 ] .


The usage of biometries in secure hallmark has many advantages but besides has many disadvantages. The chief advantages are the undermentioned: [ Braghin, 2000 ]

The user hallmark utilizing biometries is much stronger than the usage of a simple username and watchword or a smartcard. The system is able to place the individual who uses the smartcard and in that manner reduces the possibility of duplicity.

The costumier service is much more efficient. There are systems that do non necessitate designation cogent evidence by the user. Thus, a user does non hold to supply extra cogent evidence except his ain biometries. This makes security stronger against certificates which are stolen or merely lost.

User? s biometries can non be compromised. Biometricss is non something you have but something you are. So, a stolen card or a stolen watchword can non be used unless they are used by the right user.

The demand of a particular operator or employee is no longer present. Biometric secure hallmark systems do non necessitate operators to map. Of class, the whole system depends on the hallmark algorithm to do the right determination.

In general the usage of biometries in unafraid hallmark improves security and reduces cost and fraud efforts [ Crosbie, 2005 ] .

Despite the advantages there are besides many disadvantages. The chief disadvantages are the undermentioned: [ Braghin, 2000 ]

The industry does non develop criterions for the usage of biometries in unafraid hallmark. Therefore, different companies support different engineerings even for the same biometries. For illustration a store that support biometric hallmark has to possess assorted hallmark devices in order to back up minutess with multiple companies.

The engineerings that are developed for biometries hallmark are normally equal merely for a little group of people. Trials show that the engineerings that are capable to positively place a individual from a big group are merely two: fingerprints and flag. So, in order to utilize and the other biometries, progresss in engineering have to be made.

The concern of the populace is high about privateness and security issues. Privacy issues, likely is the most of import affair against the broad usage of biometries. Most of the people are concerned about the loss of their namelessness and the possible abuse of their private informations. Many people refuse to supply their biometries. Therefore the widespread usage of such engineering depends on the alteration of the populace? s position on this affair.

Distant systems can non manage good biometric hallmark systems. A major job is that the distant system has to pass on with the cardinal system in order to do the confirmation. Easily a individual can direct tampered informations. In that manner the system can be fooled. Therefore, nomadic systems are non suited for this type of hallmark. The solution relies on secure connexion.

Stolen biometric informations can non be restored. Once stolen, the biometric informations can non be renewed as a watchword or a smartcard.


Authentication that is based on biometric features is now closer to widespread execution than of all time. The advantages are really important and the disadvantages are bit by bit decreasing. Progresss in engineering can give solutions to old proficient jobs. However, the most of import job is the privateness issue. Common people are loath to give their personal informations for security use. Therefore the success of the biometries hallmark systems lies on the necessity for more security and the alteration of position of the common people on this issue.