Geldkarte

[Markus Kuhn]

Introducing new cryptographic payment options on the market seems to be
a rather difficult business, even where the banks are initially quite
enthusiastic about it. The electronic purse scheme that Germany
introduced half a decade ago is reportedly not doing too well. Two
German banks just announced that the "Geldkarte" is no longer
financially attractive for them. Only 0.3 % of the customers of Dresder
Bank and 1.5 % of the customers of the Phone/Internet bank Deutsche Bank
24 actually ever used the card, which for both does no longer justify
the cost of adding the chip to every customer card by default.

Geldkarte is a shadow-account system based on symmetric cryptography
(each customer card contains its encrypted serial number as a key,
merchant cards contain the corresponding global encryption keys).
Customers can load up to 200 EUR at any ATM onto the card, which then
can be used for secure off-line payments at merchants and vendor
machines. Geldkarte payments via Internet are under preparation. The
payment logs only have to be transfered back to the bank once every few
days via a simple file transfer and the bank will then verify the MACs
in the logs and transfer the money from the card's shadow account to the
merchant.

http://www.tagesschau.de/aktuell/meldungen/0%2c2044%2cOID810324%2c00.html
http://www.voeb-zvd.de/geldkarte.htm

Markus

-- 
Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at acm.org,  WWW: <http://www.cl.cam.ac.uk/~mgk25/>