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:
Jun. 19, 2001
Filed:
Dec. 31, 1997
James E. Gilley, Lincoln, NE (US);
Transcrypt International, Inc., Lincoln, NE (US);
Abstract
An apparatus and method for reducing the overhead of a block cipher includes shortening the length of the initialization vector so that its length is less than the length of each block of information processed by the block cipher. The block cipher is utilized in cipher block chaining mode. The shortened vector is loaded into the block cipher with other pseudo-random bits. Cipher block chaining prevents the overall cycle length of the block cipher from decreasing. Thus, channel burden of repeatedly transmitting the initialization vector is reduced because it is shorter, but security is not unduly diminished because cycle length is not diminished. Late entry can be achieved. Also, combination of this method with coasting can increase accurate synchronization even in severely corrupted channels. Security level versus amount of vector shortening can be selected.