Smart card having a plurality of data fields with reference zones and validation bits
AssigneeFrance Telecom
InventorMartial Menconi
Life of this patent
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Abstract
A method of preventing removal of a smart card having a counter zone associated with a first reference zone, and a balance zone associated with a second reference zone. The counter zone has at least two levels of counters, each having at least two bits. The counter zone is operable in accordance with the abacus principle. The first reference zone has at least one register with at least two bits and is operable to display the proper erasing of the counters. The second reference zone has at least two fields. Bits of a balance are written simultaneously in the balance zone and in the second reference zone. The balance zone and the second reference zone each include one validation bit making it possible to know if the balance is fully written.
Claims9
Method for preventing removal of a smart card used in a purse mode, wherein:
- a validation bit makes it possible to clearly know if a balance present is fully written, the validation bit being positioned when implementing a double writing mechanism, the balance being regarded as not written if the validation bit is not positioned;
- a transaction resumption mechanism on a basis of a prior balance which depends on a reference zone of a data field structured into two fields.
Dependencies are inferred from the claim text.