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. 14, 1998
Filed:
Mar. 05, 1997
James E Gilley, Lincoln, NE (US);
Transcrypt International, Inc., Lincoln, NE (US);
Abstract
A method and apparatus for generating truly random numbers which may be used in a cryptographic key generator is adapted to extract entropy from the output signal of an RC oscillating circuit comprised of a resistor, a capacitor, and two nand gates. The entropy data is extracted by comparing the period of a first cycle with the period of a second cycle where the first and second periods are separated by two cycles. If the compared periods are equal, the data is discarded. If the previous period is greater than the later period, a '1' is assigned to a shift register. Otherwise, a '.O slashed.' is assigned to the shift register. In this way, a plurality of bits are assigned to the shift register. A routine is then called which processes the bit data to reduce any cycle to cycle data correlation.