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. 25, 2014
Filed:
Jun. 30, 2010
Marco Macchetti, Cheseaux-sur-Lausanne, CH;
Henri Kudelski, Chexbres, CH;
Marco Macchetti, Cheseaux-sur-Lausanne, CH;
Henri Kudelski, Chexbres, CH;
Nagravision S.A., Cheseaux-sur-Lausanne, CH;
Abstract
The present invention provides a solution to the problem of guaranteeing the integrity of software programs by encrypting all or part of each instruction of a program using a key based on all or part of one or a plurality of previous instructions, thus resulting in a different encryption key per instruction. The invention is applicable to software programs whose structures are not necessarily tree-like in nature and is also applicable when the program includes loops, jumps, calls or breaks etc. The invention allows for an exception to be flagged when an encrypted instruction is wrongly decrypted. There is no need for the first instruction to be in clear, since the instruction key may be appropriately initialized as required. The invention can be realized in software or entirely in hardware thereby eliminating the possibility of a third party intercepting a decrypted instruction or a decryption key.