Researchers outwit forgers

Professor Wolfgang Eberhardt, the Director at the Jülich Institute for Solids Research, and his assistant, Jan Morenzin, have invented a new authenticity scheme to protect credit cards from forgery.

Professor Wolfgang Eberhardt, the Director at the Jülich Institute for Solids Research, and his assistant, Jan Morenzin, have invented a new authenticity scheme to protect credit cards from forgery.

The system, which is also suitable for banknotes, is based on the combination of wafer-thin metal layers. In the course of the manufacturing process, a digital code which can then no longer be altered is incorporated into these layers. Using conventional magnetic reader technology, it can be deciphered and its authenticity checked.

‘The information on conventional magnetic strips is relatively easy to alter,’ says Jan Morenzin, drawing a colleague’s ‘expired’ card through a commercially available reading device for magnetic cards. Three brown bars with numerical codes appear on his computer monitor. They contain the bank sorting code, the account number and other account information. This data can be picked off and manipulated without any major difficulties. Some credit-card fraudsters simply copy the illegally acquired data from one card on to other cards and thus gain access to other people’s accounts.

The new strip, on the other hand, consists of a lot of thin layers of one particular metal. Spatially distinguishable areas with different magnetisation directions are then produced in one of the middle layers. Depending on whether the magnetised area is oriented ‘upwards’ or ‘downwards’, it contains the digital information ‘1’ or ‘0’. Because there is space for a very great number of ones and zeros (bits) on the new magnetic strip, it is known as a multi-bit system.

‘A multi-bit system opens up completely new security perspectives with regard to quality,’ Morenzin explains. Until now, many authenticity characteristics function with just one or a few one-bit systems, e.g. the hologram or the photograph on credit cards. The holograms on today’s credit cards do not contain any information about the cardholder. The cash dispensers merely check whether the hologram is present or not. And the photograph which is intended to tie the card to one person can be replaced by forgers. ‘It would be safer and easier to store a lot of different security characteristics, also tied to the person, on a single forgery-proof strip and that can be achieved by the new system,’ says Morenzin.

Furthermore, the Jülich magnetic strip (in contrast with the current cash cards) is insensitive to external magnetic fields. Morenzin takes a small magnet out of his desk drawer and passes it over the magnetic strip of his colleague’s EC card and over the ‘demo card’ with the new strip. A check with the reading device shows that the data on the EC card has been deleted while that on the demo card can still be read.

‘We are now developing a cheap manufacturing process for the magnetic strips,’ says Professor Eberhardt.

Forschungszentrum JülichD – 52425 Jülich,Germany Email: fzj@fz-juelich.de