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:
Jul. 01, 1986
Filed:
May. 17, 1984
Gerald V Piosenka, Scottsdale, AZ (US);
Barry B Mead, Mesa, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An apparatus and method is disclosed for the protection of computer programs through the use of the principles of conditional inversion and permutation. These security features are designed as part of the chip in a fashion to minimize the changes required to any existing microprocessor design and to be transparent to firmware execution. The programs are first encrypted by permutation which reorders the lines according to an allocated scheme and then conditionally inverted through a set of dual input exclusive OR gates. The reordering of lines in the permutator and the conditional inversion in the inverter are accomplished through the use of variables some of which are permanently prestored in the microprocessor and some of which are entered by the programmer.