The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 2009
Filed:
Jan. 20, 2004
Marc Girault, Caen, FR;
Marc Girault, Caen, FR;
France Telecom, Paris, FR;
Abstract
An asymmetrical cryptographic method of protecting an electronic chip against fraud in transactions between the electronic chip and an application, involving calculating an authentication value V from input parameters in the electronic chip. The chip produces a pseudo-random number r specific to the transaction by means of a serial pseudo-random generator included in the chip. The chip sends the application a parameter x calculated by the application prior to the transaction, linked to the random number r by a mathematical relationship, and stored in a data memory of the chip. The chip calculates a parameter y constituting the whole or a portion of the authentication value V by means of a serial function whose input parameters are at least the random number r specific to the transaction and a private key s belonging to an asymmetrical pair of keys. The chip sends the authentication value V to the application, and the application verifies the authentication value V by means of a verification function whose input parameters consist exclusively of public parameters including at least the public key p.