Method for creating a secure counter on an on-board computer system comprising a chip card
AssigneeTrusted Logic
InventorsAlexandre Frey, Dominique Bolignano, Axelle Apvrille
Life of this patent
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Abstract
According to the inventive method, the chip card, a counting function (FC), a counter (Cpt) and a private key (Cf) stored in the write-only part of the memory region are stored in a persistent memory, the counter and the private key (Cf) being accessible only by the counting function (FC). When the chip card receives a counter request emitted by an requesting entity (ER), the counting function (FC) performs a modification of the counter (Cpt) and a calculation of a signature, and sends a response to the applicant entity (ER). When the on-board system receives the response to the counter request, the signature contained in the response is checked.
Claims9
A method to provide a secure counter on an embedded system having a chip card, the embedded system comprising a non re-writable public persistent memory;
- the method comprising the following operating phases:
- (i) storing, in a private persistent memory of the chip card:
- a counting function, a counter, and a private key stored in a re-writable read-protected part of the private persistent memory, the counter and the private key being accessible solely by the counting function;
- (ii) executing, upon receipt by the chip card of a counter request emitted by a requesting entity, the following operations:
- (a) modifying, by the counting function, the counter ensuring uniqueness of a counter value given in reply to a given request,
- (b) calculating, by the counting function, a signature using the value of the counter modified at operation (a) and the private key;
- (c) sending, by the counting function, a reply to the requesting entity, the reply including the value of the counter modified at operation (a) and the signature calculated at operation (b);
- (iii) verifying, upon receipt by the requesting entity of the reply to the requesting entity, the signature contained in the reply to the requesting entity with a public key or an associated public key certificate of the private key.
Dependencies are inferred from the claim text.