| US 7,502,464 B2 | ||
| Method of implementing one-to-one binary function and relative hardware device, especially for a Rijndael S-box | ||
| Marco Macchetti, Lodi (Italy); Pasqualina Fragneto, Milan (Italy); and Guido Marco Bertoni, Cusano Milanino (Italy) | ||
| Assigned to STMicroelectronics S.r.l., Agrate Brianza (Italy) | ||
| Filed on Apr. 02, 2004, as Appl. No. 10/816,791. | ||
| Claims priority of application No. 03425211 (EP), filed on Apr. 04, 2003. | ||
| Prior Publication US 2004/0228482 A1, Nov. 18, 2004 | ||
| Int. Cl. H04L 9/00 (2006.01) | ||
| U.S. Cl. 380—37 [380/29] | 15 Claims |
| 1. A method for generating output bytes corresponding to respective input bytes according to a one-to-one binary function
representing a cryptographic algorithm, the method comprising:
decoding an input byte and generating at least one bit string that contains only one active bit, with the decoding comprising
subdividing the input byte into a left nibble and a right nibble, and decoding the left nibble and right nibble into a left
16-bit string and a right 16-bit string, respectively, each 16-bit string containing only one active bit;
using an array of logic gates for logically combining the 16-bit strings according to the one-to-one binary function and generating
an encrypted 256-bit string without the use of a lookup table; and
encoding the encrypted 256-bit string for obtaining an output byte for the cryptographic algorithm.
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