Monday, November 19, 2007

A Wallet Full Of Cards

We are today in the age of plastic cards. Obvious uses that comes to mind immediately are payment cards - credit cards and debit cards. We also use plastic for train/bus passes, loyalty card for shops, frequent flyer card, to open doors at homes and hotels and so on and so forth. I personally carry more plastic in my wallet than everything else put together.

Won't it be wonderful if we could carry just one card and choose what we want it to be? My dream device would be another plastic card:
  • similar size as a regular credit card
  • magnetic heads to play track information on the lower portion of the card
  • the same heads should be able to record magnetic information from an existing card when it is passed over it
  • with electronics that can control the magnetic head
  • with bluetooth that can communicate with an external secure storage device (my mobile phone!)
  • a small battery to power it
So once I get a new card, I would go ahead and make a copy of it using my special card reader onto my mobile phone. The information on my phone would be encrypted and password protected (and self destructing if I don't touch the phone for more than half a day). When I have to swipe my shopper stop card, I'll flick out my phone, choose shopper stop and hand over my special card at the counter! If I lost my card, well I just need to get a new card. If I lost my phone, I still have my card and the card application on the phone would work only with my card. If I lost both, well my password is super strong and the application would self destruct anyway.

It shouldn't be so difficult to do it also - after all they are just another form of the good old music tapes. The plastic card magnetic stripe has actually 3 tracks of information. The music tape had four; two tracks (for stereo) on each of two sides. The magnetic stripe reader head is similar to the music cassette player head.

Some information of magnetic stripes:
Has someone done it already? A quick search for patents in Google throws up plenty of them. But surprisingly not too many products built using it.
  • Here's a couple of pages with how to build one for yourself.
  • Vivocard. However the product page on their website does not mention this explicitly.
  • Tyfone is trying out magstripe emulation in the context of mobile banking.
  • iCache is planning something very similar but with a much larger device. It will have limited availability next year. It would be really good if iCache hardware could be integrated with a mobile phone so that we don't have to carry around too many devices.
Acceptance of such cards at merchant outlets would be a major stumbling block for obvious security reasons. It is not surprising therefore that both iCache and Tyfone are launching this only in the context of a bank. However, I believe the scheme can be made as secure as regular credit cards by using the mobile phone as a storage medium and consumer authorizing the bank to send the encrypted card over the air to his mobile. If successful this could be a significant breakthrough in mobile commerce. It could use the millions of existing cheap magnetic stripe readers everywhere. Cards can be more secure - can be issued and expired more often at a fraction of the cost today.

Fingerprinting magstripes:
  • Magensa
  • ValuGard® from Rand McNally - ValuGard uses the inherent signal amplitude properties of the stripe
  • Watermark Magnetics® from Thorn Secure Science International - Watermark Magnetics uses a special magnetic stripe
  • XSec® from XTec, Inc. - uses the inherent jitter properties of the stripe


Anonymous said...

For reference, the "Magnetic Fingerprinting" method used by MAGENSA is known as "MagnePrint".
MagnePrint is exclusively licensed by MagTek Inc. Carson, CA.
For more info see;

MagnePrint is based upon the discovery that all magnetic stripes are intrinsically unique due to the micro particle structure of iron-oxide material that comprises each magnetic stripe. Every magstripe is unique from the time it is manufactured, and prior to any man-made data being encoded on the stripe. MagnePrint can detect and prevent the use of counterfeit magstripe cards. It also allows a magstripe card to be used as a unique "physical token" as part of a multifactor authentication security scheme.
With MagnePrint, there is no need to reissue cards to consumers. The magstripe cards in their wallets are already "MagnePrint enabled", and ready for use.

Tanmay said...

Thanks for the additional information!