Secured computerized credit cards of the ferromagnetic storage variety, and a computer system that makes use of such cards at more than one geographic location. The card comprises a plurality of ferromagnetic elements, capable of storing binary indicia, sandwiched between thin sheets of plastic or other...http://www.google.com/patents/US4055746?utm_source=gb-gplus-sharePatent US4055746 - Method of and apparatus for securing and storing personal information
