Showing papers on "MDS matrix published in 2007"
Patent•
29 Aug 2007TL;DR: In this article, the authors provided a highly secure cryptographic processing apparatus and method where an analysis difficulty is increased by increasing the minimum number (a robustness index against a differential attack in common key block encryption) of the active S box in the entire encryption function.
Abstract: There is provided a highly secure cryptographic processing apparatus and method where an analysis difficulty is increased. In a Feistel type common key block encrypting process in which an SPN type F function having a nonlinear conversion section and a linear conversion section is repeatedly executed a plurality of rounds. The linear conversion process of an F function corresponding to each of the plurality of rounds is performed as a linear conversion process which employs an MDS (Maximum Distance Separable) matrix, and a linear conversion process is carried out which employs a different MDS matrix at least at each of consecutive odd number rounds and consecutive even number rounds. This structure makes it possible to increase the minimum number (a robustness index against a differential attack in common key block encryption) of the active S box in the entire encrypting function.
49 citations
Patent•
29 Aug 2007TL;DR: In this article, the authors proposed a high-security cryptographic processing apparatus that increases difficulty in analyzing the key of a common-key-block cipher, and a method therefor, to realize cryptographic processing whereby resistance to linear cryptanalysis attacks in the Common-Key-Block cipher is improved.
Abstract: The invention realizes a high-security cryptographic processing apparatus that increases difficulty in analyzing its key and a method therefor. In Feistel-type common-key-block cryptographic processing that repeatedly executes an SPN-type F-function having the nonlinear conversion section and the linear conversion section over a plurality of rounds, Linear conversion processing of an F-function corresponding to each of the plurality of rounds is carried out by linear conversion processing that applies square MDS (Maximum Distance Separable) matrices. The invention uses a setting that arbitrary m column vectors included in inverse matrices of square MDS matrices being set up at least in consecutive even-numbered rounds and in consecutive odd-numbered rounds, respectively, constitute a square MDS matrix. This structure realizes cryptographic processing whereby resistance to linear cryptanalysis attacks in the common-key-block cipher is improved.
34 citations