Key protection device for smart cards
AssigneeBull CP8
InventorMichel Hazard
Life of this patent
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Abstract
This invention concerns a key protection device for smart cards and is characterized by the fact that: each input user key is coded using a random key and stored; protection data that corresponds to each coded user key's dependant data is generated and associated to each coded user key; a detection device is installed on the card that allows the user to verify the stored user key's integrity by comparing the protection data to verification data that is generated using the card's stored user key; and an interlock device that allows the user to block any further calculation using the stored key in the event that the verification data is not identical to the protection data.
Claims14
A user key protection device for a smart card comprising:
- at least one user coded key stored within said smart card, said at least one user coded key is coded (CCCi) using a specific key specific to each smart card, a user key, and a user key coding/decoding algorithm (A.S.C.C.) executed by a microprocessor within said smart card;
- protection data corresponding to dependent data of each of said at least one user coded key generated and stored in association with a respective at least one user coded key (CCCi) in a memory area of said smart card;
- a detection device installed in said smart card allowing the smart card to verify integrity of said at least one user coded key (CCCi) by comparing said protection data to verification data generated using the at least one user coded key (CCCi);
- and
- an interlock device installed in the smart card allowing the smart card to block any further calculation using the at least one user coded key (CCCi) in the event that said verification data is not identical to said protection data.
A process for storing at least one user coded key in a smart card, comprising the steps of:
- receiving a user key;
- coding said user key into a user coded key using a specific key specific to each smart card and a user key coding/decoding algorithm (A.S.C.C.) executed by a microprocessor within said smart card;
- calculating protection data using said user coded key and a test algorithm (A.C.A.S.C.) executed by said microprocessor;
- and
- storing said user coded key in association with said protection data in a memory area of said smart card.
Dependencies are inferred from the claim text.