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:
Oct. 11, 1983
Filed:
Dec. 01, 1980
Jean-Claude Basset, Paris, FR;
Alain Meinguss, Meudon la Foret, FR;
Electronique Marcel Dassault, Paris, FR;
Abstract
In a transaction card such as a credit or payment card provided with an integrated circuit for performing and recording the transaction, communications between the card and an access terminal must be coded so as to prevent fraud attempts. An integrated circuit coding device for coding or decoding a message in accordance with a confidential coding key comprises active transistors, and passive transistors, i.e. permanently blocked and/or permanently conductive, interconnected in such a way that observation of such circuit by means of an electronic microscope does not allow the determination of the confidential key which is implemented by the circuit.