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:
Feb. 13, 2001
Filed:
Jun. 05, 1998
Don Coppersmith, Ossining, NY (US);
Rosario Gennaro, New York, NY (US);
Shai Halevi, Heartsdale, NY (US);
Charanjit S. Jutla, Elmsford, NY (US);
Stephen M. Matyas, Jr., Manassas, VA (US);
Luke James O'Connor, Adliswil, CH;
Mohammed Peyravian, Cary, NC (US);
David Robert Safford, Brewster, NY (US);
Nevenko Zunic, Wappingers Falls, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The present invention provides a technique, system, and computer program for a symmetric key block cipher. This cipher uses multiple stages with a modified Type-3 Feistel network, and a modified Unbalanced Type-1 Feistel network in an expansion box forward function. The cipher allows the block size, key size, number of rounds of expansion, and number of stages of ciphering to vary. The modified Type-3 cipher modifies the word used as input to the expansion box in certain rounds, to speed the diffusion properties of the ciphering. The modified Type-3 and Type-1 ciphers are interleaved, and provide excellent resistance to both linear and differential attacks. The variable-length subkeys and the S-box can be precomputed. A minimal amount of computer storage is required to implement this cipher, which can be implemented equally well in hardware or software (or some combination thereof).