January 2, 2015

Some data for this post is taken from “Biometrics”

Biometrics is the science and technology of measuring and analyzing biological data. In information technology, biometrics refers to technologies that measure and analyze human body characteristics, such as DNA, fingerprints, eye retinas and irises, voice patterns, facial patterns and hand measurements, for authentication purposes.  Now, the definition of authentication is: the process of determining whether someone or something is, in fact, who or what it is declared to be. The greatest use of biometric data is to prevent identity theft.  With this being the case, biometric data is usually encrypted when it’s gathered. Here’s how biometric verification works on the back end: To convert the biometric input, a software application is used to identify specific points of data as match points. The match points in the database are processed using an algorithm that translates that information into a numeric value. The database value is compared with the biometric input the end user has entered into the scanner and authentication is either approved or denied.

Let’s now take a look at the following areas to get a fairly complete picture of how biometrics is used.


Humans have twenty-three (23) pairs of chromosomes containing DNA blueprint. One member of each chromosomal pair comes from the mother; the other comes from their father. Every cell in a human body contains a copy of this DNA. The large majority of DNA does not differ from person to person, but 0.10 percent of a person’s entire genome would be unique to each individual. This represents 3 million base pairs of DNA.

Genes make up five percent (5%) percent of the human genome. The other ninety-five percent (95%) percent are non-coding sequences, (which used to be called junk DNA). In non-coding regions there are identical repeat sequences of DNA, which can be repeated anywhere from one to thirty (30) times in a row. These regions are called variable number tandem repeats (VNTRs). The number of tandem repeats at specific places (called loci) on chromosomes varies between individuals. For any given VNTR loci in an individual’s DNA, there will be a certain number of repeats. The higher number of loci are analyzed, the smaller the probability to find two unrelated individuals with the same DNA profile.

DNA profiling determines the number of VNTR repeats at a number of distinctive loci, and use it to create an individual’s DNA profile. The main steps to create a DNA profile are: isolate the DNA (from a sample such as blood, saliva, hair, semen, or tissue), cut the DNA up into shorter fragments containing known VNTR areas, sort the DNA fragments by size, and compare the DNA fragments in different samples.

It’s a big gruesome but forensic identifications using DNA matching provide the most positive methods for determining an individual—living or dead.


Fingerprints have been used by law enforcement for year now and offer an infallible means of personal identification. That is the essential explanation for fingerprints having replaced other methods of establishing the identities of criminals reluctant to admit previous arrests. Fingerprints are the oldest and most accurate method of identifying individuals. No two people (not even identical twins) have the same fingerprints, and it is extremely easy for even the most accomplished criminals to leave incriminating fingerprints at the scene of a crime.

A fingerprint is made of a number of ridges and valleys on the surface of each finger. Ridges are the upper skin layer segments of the finger and valleys are the lower segments. The ridges form so-called minutia points: ridge endings (where a ridge end) and ridge bifurcations (where a ridge splits in two). Many types of minutiae exist, including dots (very small ridges), islands (ridges slightly longer than dots, occupying a middle space between two temporarily divergent ridges), ponds or lakes (empty spaces between two temporarily divergent ridges), spurs (a notch protruding from a ridge), bridges (small ridges joining two longer adjacent ridges), and crossovers (two ridges which cross each other).

The uniqueness of a fingerprint can be determined by the pattern of ridges and furrows as well as the minutiae points. There are five basic fingerprint patterns: arch, tented arch, left loop, right loop and whorl. Loops make up sixty percent (60%) of all fingerprints, whorls account for thirty percent (30%), and arches for ten percent (10%).

Fingerprints are usually considered to be unique, with no two fingers having the exact same dermal ridge characteristics.

How does fingerprint biometrics work

The main technologies used to capture the fingerprint image with sufficient detail are optical, silicon, and ultrasound.

There are two main algorithm families to recognize fingerprints:

  • Minutia matching compares specific details within the fingerprint ridges. At registration (also called enrollment), the minutia points are located, together with their relative positions to each other and their directions. At the matching stage, the fingerprint image is processed to extract its minutia points, which are then compared with the registered template.
  • Pattern matching compares the overall characteristics of the fingerprints, not only individual points. Fingerprint characteristics can include sub-areas of certain interest including ridge thickness, curvature, or density. During enrollment, small sections of the fingerprint and their relative distances are extracted from the fingerprint. Areas of interest are the area around a minutia point, areas with low curvature radius, and areas with unusual combinations of ridges.


Retina scans require that the person removes their glasses, place their eye close to the scanner, stare at a specific point, and remain still, and focus on a specified location for approximately ten (10) to fifteen (15) seconds while the scan is completed. A retinal scan involves the use of a low-intensity coherent light source, which is projected onto the retina to illuminate the blood vessels which are then photographed and analyzed. A coupler is used to read the blood vessel patterns.

A retina scan cannot be faked as it is currently impossible to forge a human retina. Furthermore, the retina of a deceased person decays too rapidly to be used to deceive a retinal scan.

A retinal scan has an error rate of 1 in 10,000,000, compared to fingerprint identification error being sometimes as high as 1 in 500.

An iris scan will analyze over 200 points of the iris, such as rings, furrows, freckles, the corona and will compare it a previously recorded template.

Glasses, contact lenses, and even eye surgery does not change the characteristics of the iris.

To prevent an image / photo of the iris from being used instead of a real “live” eye, iris scanning systems will vary the light and check that the pupil dilates or contracts.


Speech includes two components: a physiological component (the voice tract) and a behavioral component (the accent). It is almost impossible to imitate anyone’s voice perfectly. Voice recognition systems can discriminate between two very similar voices, including twins.

The voiceprint generated upon enrolment is characterized by the vocal tract, which is a unique a physiological trait. A cold does not affect the vocal tract, so there will be no adverse affect on accuracy levels. Only extreme vocal conditions such as laryngitis will prevent the user from using the system.

During enrollment, the user is prompted to repeat a short passphrase or a sequence of numbers. Voice recognition can utilize various audio capture devices (microphones, telephones and PC microphones). The performance of voice recognition systems may vary depending on the quality of the audio signal.

To prevent the risk of unauthorized access via tape recordings, the user is asked to repeat random phrases.


Biometric hand recognition systems measure and analyze the overall structure, shape and proportions of the hand, e.g. length, width and thickness of hand, fingers and joints; characteristics of the skin surface such as creases and ridges. Some hand geometry biometrics systems measure up to ninety 90 parameters.

As hand biometrics rely on hand and finger geometry, the system will also work with dirty hands. The only limitation is for people with severe arthritis who cannot spread their hands on the reader.

The user places the palm of his or her hand on the reader’s surface and aligns his or her hand with the guidance pegs which indicate the proper location of the fingers. The device checks its database for verification of the user. The process normally only takes a few seconds.

To enroll, the users place his or her hand palm down on the reader’s surface.

To prevent a mold or a cast of the hand from being used, some hand biometric systems will require the user to move their fingers. Also, hand thermography can be used to record the heat of the hand, or skin conductivity can be measured.


Biometric signature recognition systems will measure and analyze the physical activity of signing, such as the stroke order, the pressure applied and the speed. Some systems may also compare visual images of signatures, but the core of a signature biometric system is behavioral, i.e. how it is signed rather than visual, i.e. the image of the signature.


As you well know, identity theft is a HUGE problem across the world.  Trans Union tells us the following:

  • Identity theft is the fastest growing crime in America.
  • The number of identity theft incidents has reached 9.9 million a year, according to the Federal Trade Commission.
  • Every minute about 19 people fall victim to identity theft.
  • It takes the average victim an estimated $500 and 30 hours to resolve each identity theft crime.
  • Studies have shown that it’s becoming more common for the ones stealing your identity to be those closest to you. One study found 32% of identity theft victims discovered a family member or relative was responsible for stealing their identity. That same study found 18% were victimized by a friend, neighbor or in-home employee.
  • Most cases of identity theft can be resolved if they are caught early.
  • Financial institutions – like banks and creditors – usually only hold the victim responsible for the first $50 of fraudulent charges.
  • Only 28% of identity theft cases involve credit or financial fraud. Phone, utility, bank and employment fraud make up another 50% of cases.

These are sobering numbers but reflect reality.  The incorporation of biometrics just may be a partial answer to theft prevalent today.  As always, I welcome your comments.


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