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. 26, 2007
Filed:
Mar. 29, 2002
Chih-chung LU, Shulin, TW;
Shau-yin Tseng, Hsinchu, TW;
Chih-Chung Lu, Shulin, TW;
Shau-Yin Tseng, Hsinchu, TW;
Industrial Technology Research Institute, Hsinchu, TW;
Abstract
An apparatus for encryption and decryption, capable of use in encryption and decryption of advanced encryption standard. Byte substitution operation and inverse byte substitution operation are to be combined. Byte substitution operation can be expressed as y=M*multiplicative_inverse(x)+c while inverse byte substitution operation can be expressed as x=multiplicative_inverse(M*(y+c)), wherein M and Mare inverse matrix of each other and c is a constant matrix. Since the two equations employ a look-up table, that is, multiplicative_inverse(x), the lookup tables for use in byte substitution and inverse byte substitution operations are to be combined according to the invention so as to lower hardware complexity of the implementation. In addition, main operations of column mixing operation and inverse column mixing operation are to be rearranged to combine the two operations in part, resulting in simplified hardware implementation.