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:
Feb. 26, 2019
Filed:
Nov. 10, 2017
Renesas Electronics Corporation, Tokyo, JP;
Daisuke Oshida, Tokyo, JP;
Renesas Electronics Corporation, Tokyo, JP;
Abstract
To raise confidentiality of the value stored in the ROM, in an IC having a built-in or an externally-attached ROM storing a value (program and/or data) encrypted using a predetermined cryptographic key. The IC includes the ROM storing the encrypted value (program and/or data), a unique code generating unit, and a decrypting unit. The unique code generating unit generates a unique code specifically determined by production variation. The decrypting unit calculates a cryptographic key on the basis of the generated unique code and a correction parameter, and decrypts the encrypted value read out from the ROM by using the calculated cryptographic key. The correction parameter is preliminarily calculated outside the IC, on the basis of an initial unique code generated from the unique code generating unit immediately after production of the IC, and the predetermined cryptographic key used for encryption of the value to be stored in the ROM.