Passwords move on – biometrics enter!

March 3rd, 2014, Published in Articles: EngineerIT


by Hans van de Groenendaal, features editor,  EngineerIT

For the past five or more years, the debate on biometrics versus passwords has been the subject of many media releases and articles. Although biometrics technology has advanced during that time, many institutions and people are still hanging onto the passwords. All this despite reports that people are careless with passwords, selecting inappropriate ones like “password”, or “1234” and making themselves vulnerable to fraud.

The South African government recently said that if banks would change their ATMs to use biometrics  – specifically fingerprint technology – they would be able to stop the huge amount of fraudulent pension and grant payouts almost overnight. Because of the lack of biometrics at ATMs they have had to resort to using a much more complicated voice system that in conjunction with ATM pin numbers will eliminate the waste of millions paid monthly to people that have long since  passed on. Biometrics would have done it more accurately and with less inconvenience to the pensioner or grant recipients.

Biometric systems provide fixing of the identity of a person in an automated manner. For this to be successful the biometric sensor needs to be able to collect useful data over a wide range of conditions in which it operates. Fingerprint sensing is one of the most widely deployed of all biometric technologies. There are many techniques for capturing a fingerprint image including optical, capacitive, radio frequency, ultrasound and thermal methods. The common shortcoming of many earlier fingerprint sensing technologies is the frequent occurrence of poor quality images under a variety of common operational circumstances.

Fig.1: Fingerprint sensor in action.

Fig.1: Fingerprint sensor in action.

“But technology has moved on”, says Greg Sarrail, vice-president of Lumidigm. “To address the shortcomings of earlier systems an optical fingerprint sensor has been developed that is able to work across the range of operational conditions while also providing spoof detection. The newer sensors are based on multi-spectral imaging (MSI) and are configured to image both the surface and the subsurface characteristics of the finger under a variety of optical conditions.”

The combination of surface and subsurface imaging ensures that useable biometric data can be taken across a wide range of environmental and physiological conditions. Bright ambient lighting, moisture, poor contact between finger and sensor, dry skin, and various topical contaminants present little impediment to collecting useable data.

Fig. 2:  Multi-spectral imaging subsurface capability.

Fig. 2: Multi-spectral imaging subsurface capability.

The MSI sensor collects multiple images of the finger under a variety of conditions. The raw images are captured using different wavelength of illumination light, different polarisation conditions and different illumination orientation. In this way each of the raw images contains somewhat different and complementary information about the finger. The different wavelengths penetrate the skin to different depths and are absorbed and scattered differently by various chemical components and structures in the skin. The different polarisation conditions change the degree of contribution of surface and subsurface to the raw image. Different illumination orientations change the location and degree to which surface features are accentuated.

A customised algorithm is used to fuse multiple raw MSI images into a single high quality composite fingerprint image. This single fingerprint can be used to match other MSI fingerprint images as well as images collected using other methods. The MSI fingerprint is backward compatible and can be used with existing fingerprint databases collected with different imaging technologies.

“I believe that resistance to replace passwords with fingerprint technology is based on outdated beliefs about biometrics”, says  Sarrail.  It is often said that biometrics does not offer the same privacy as other technologies.  MSI imaging is at any time more private then a password can ever be. Another myth about biometrics belongs to the science fiction and  NCIS TV programmes, “a stolen finger can fake the system.”

A classification methodology has been developed to operate on MSI data and determines if the properties of the sample are consistent with those of live human skin.  MSI technology coupled with various developed algorithms can identify if a finger is alive or not,  so faked fingers will not be recognised.

Sarrail says that it is his belief that following widespread acceptance of fingerprint technology in many sectors  of industry, it will ultimately be adopted by the banks for use on ATMs. It will make transactions safer and overcome the problem of poor passwords and those written in a diary or on a scrap of paper in the person’s wallet.

While fingerprint technology is perhaps the most likely technology to be accepted currently, other technologies such  as iris, facial  and voice recognition are not that far behind in their development. Will passwords and pin numbers eventually be replaced by biometrics? Definitely – as Apple has already shown!

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