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. 07, 2004
Filed:
Feb. 08, 2000
George W. Wilhelm, Jr., Endwell, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
Tamper resistance is provided to avoid observation of the behavior of portions of software by calling a function exclusively available in one differentiated section of a processor and its peripherals and drivers from another differentiated section. A pseudo-random binary sequence generator is associated with each such differentiated section and incremented incident to the calling and performance of the function, respectively. The pseudo-random binary sequence values are compared prior to allowing or preventing further execution of the software. The comparison can be performed at any privilege level and a variation of the invention provides additional security by utilizing an additional privileged function to perform the comparison. An enhancement of the invention corrupts data or program files using a PRBS value at one privilege level and performs the inverse function to restore the data or program files at another privilege level with its own PRBS value.