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. 10, 2026
Filed:
Sep. 09, 2024
Lexmark International, Inc., Lexington, KY (US);
Timothy John Rademacher, Richmond, KY (US);
LEXMARK INTERNATIONAL, INC., Lexington, KY (US);
Abstract
A method of determining the authenticity of a replaceable toner cartridge in a printing device using an elliptic curve E defined over a finite field F, where q is an integer, the method comprising: the printing device generating a random integer j, where the random integer j is in the interval of one to the integer q; the printing device calculating a point T=j·S, where point S is a point on elliptic curve E(F); the printing device calculating a binary value k which is equal to the binary random integer j with a bitmask m applied thereto; the printing device sending point T and binary value k to the replaceable toner cartridge; and the replaceable toner cartridge iteratively calculating point U=n·S for different values of integer n, where for each iterative calculation integer n takes different values.