research activities in 2007 - CSEM

Counterfeit – Machine Readable Covert Security Feature
J. Pierer, U. Gubler, N. Blondiaux, R. Pugin, C. Keck, H. Walter
By combining Micro and Nano technologies CSEM has developed a security system to directly mark products and verify their authenticity.
Due to forged products various industry sectors experience
huge damages accounting to several hundred billion US
Dollars a year [1] . Consequently, extensive efforts are made to
increase protection of products at risk. The development and
implementation of new security systems opens a huge market
to be exploited.
However, to understand this market, one has to understand
the characteristics of security features. Most safety features
and safety equipment are safe only for a short period of time,
depending on how long it takes for forgers to counterfeit the
technique. Extending the secure period of a safety device is
therefore one of the most important requirements when
developing new security systems.
In order to meet these requirements, CSEM designed a new
system showing two main characteristics:
• A random pattern [2] which is difficult to be copied was
developed as a main security feature
• In order to read those random patterns an instrument was
developed which is able to read those features’, but is no
use to somebody who does not know what to look for.
By process control these patterns can be designed to meet
certain specifications with regard to the features of average
size and consequently average period. Their organization,
however, remains completely random.
The coherent light of a laser is used to illuminate the pattern.
The light is scattered on each element of the structure. Every
single element can then be seen as a new source of light.
Investigating the intensity of the scattered light at any point in
space will result in a value given by the superposition of the
light of all these sources. Depending on incidence angle,
structure period and wavelength of the light one gets a
particular intensity distribution. However, since the features
are randomly aligned the image shows a so called speckle
pattern (Figure 1).
Figure 1: Image of a speckle pattern on a paper target, left: small
spot illuminated, right: large spot illuminated
When illuminating a small spot of the security feature (about
30 µm) a well distinguishable speckle pattern becomes
visible. By enlarging this area up to a few millimetres, the
speckles are averaged and a smooth distribution is visible.
10
Analyzing characteristic parameters of the speckle pattern or
the smooth distribution identifies uniquely either a particular
security item (e.g. credit card) or the technology with which
the pattern was created. We have built a small electronic
prototype to demonstrate the feasibility and ruggedness of this
new technique.
A small laser diode with an integrated focusing lens was used
as source, a silicon photodiode array as detector to build the
prototype. All components, including a micro controller, were
assembled on a printed circuit board. The micro controller
compares the sample under investigation with an inbuilt
reference and communicates the result via a green/red LED to
the human observer. For obvious reasons credit cards were
chosen to demonstrate the new security feature. The credit
card is inserted into the device through a standard smartcard
holder. The cardholder holds the credit card in place with a
repeatable accuracy exceeding 40 µm, which is sufficient for
these purposes. As can be seen in Figure 2 the entire setup
fits into a small box leaving plenty of space.
Figure 2: Demonstrator
The results of this project have proven that the implementation
of these newly developed security features is possible with
very simple low cost components. CSEM security system is
difficult to counterfeit and is mass producible. The developed
authentication device is easy to use, compact and can be built
in into other devices, such as automatic teller machines.
CSEM new security features offer a promising way to prevent
counterfeiting for an extended period of time.
[1] G. W. Abbot, L. S. Sporn, Trademark Counterfeiting § 1.03[A]
[2] Patents pending