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:
Dec. 21, 1999
Filed:
Feb. 14, 1997
Matthew A Blaze, Hoboken, NJ (US);
AT&T Corp, Middletown, NJ (US);
Abstract
An efficient block cipher that operates on blocks of arbitrarily large size. A block is permuted by recursively using relatively small random functions in an N-round Feistel construction, where N is an integer. The security of the invention is closely related to the difficulty of solving the Numerical Matching with Target Sums problem, an NP Complete problem which cannot presently be solved analytically using known mathematical techniques. The memory required for the cipher's random functions increases linearly with block size, rather than exponentially as with known Feistel constructions. The invention can be efficiently and practically implemented in software at speeds comparable to the speeds of known ciphers.