MM code: Difference between revisions

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An '''MM code''' (the "MM" being an abbreviation for the [[German language|German]] "Moduliertes Merkmal") is a "machine-readable modulated" feature that has been added to German [[debit card]]s during manufacture as an anti-[[counterfeiting]] measure since 1979.<ref>{{cite book|author=Wolfgang Rankl and Wolfgang Effing|title=Handbuch der Chipkarten. 3rd edition|publisher=Hanser Verlag|year=1999|language=German}}</ref><ref>{{cite web|url=http://www.kartensicherheit.de/ww/de/pub/oeffentlich/sicherheitsprodukte/mm_merkmal.php|title=MM-Merkmal|work=|author=|publisher=|date=|accessdate=2008-01-10|language=German|archive-url=https://web.archive.org/web/20090522165336/http://www.kartensicherheit.de/ww/de/pub/oeffentlich/sicherheitsprodukte/mm_merkmal.php|archive-date=2009-05-22|url-status=dead}}</ref> It was developed by "Gesellschaft für Automation und Organisation" (a subsidiary of Giesecke & Devrient) in Munich for the German ec-Card system and MM verification devices have been added to German ATMs from 1982 onwards.<ref name="ct1996">{{cite news|author=Carsten Meyer|url=http://www.heise.de/ct/96/07/094/|title=Nur Peanuts &mdash; Der Risikofaktor Magnetkarte|work=[[c't]]|date=July 1996|pages=94|language=German|publisher=Heise Zeitschriften Verlag}}</ref> If a payment card contains an MM code as well as a magnetic stripe, any fraudster who counterfeits the card but fails to read and duplicate the MM code onto the copy will be detected when trying to use the counterfeit in a German [[automated teller machine]].

==Function==

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*'''Angle modulation of ferromagnetic particles:''' A code is embedded into the magnetic stripe using read and write heads operating diagonally to the direction of swipe in the reader. With appropriate signal processing, these can read and encode a small amount of additional data which is polarised in a different axis to the ISO standard tracks.

*'''Infrared barcodes:''' The second class concerns encoding the code onto the plastic base of the card using special inks (probably a bar code), or reading a code which is inherently embedded as part of the plastic manufacturing process for each batch. Such a code may only be visible under infrared illumination (or other invisible wavelength).

* [[ Wiegand effect #Wiegand keycards | Wiegand keycards]], like capacitive MM codes, embed a code into the middle layer of the card, and so are more durable and difficult to counterfeit than printed barcodes or magnetic stripes on the surface of the card.<ref>

[https://books.google.com/books?id=Ehc1omWy6iMC "Security Supervision and Management: The Theory and Practice of Asset Protection"].

2007.

p. 365.

</ref>

==References==