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:
Mar. 09, 1999
Filed:
Mar. 31, 1997
Vincent Rigal, Sceaux, FR;
Schlumberger Industries, Montrouge, FR;
Abstract
Security device for preventing access to confidential information stored in a semiconductor chip, or protected chip. The security device comprises a second semiconductor chip, or protective chip, with the two chips facing each other and being coupled to each other by communication terminals. The protected chip is coupled to external circuits via the protective chip, and the two semiconductor chips are separated by a semiconductor resin having a non-homogeneous electrical resistivity. The protective chip is provided with means for measuring a plurality of resistances through the semiconductor resin and with means for determining, at least from the measured resistances, an encryption key intended to be communicated to the protect chip to protect the confidential information.