Encryption method, decryption method, device, and program

TL;DR: In this article, a common-key block cipher based on the DSM with a high resistance to linear analysis and differential analysis is realized, where a plurality of different matrices satisfying a condition in which a minimum number of branches for all of the data lines is equal to or more than a predetermined value are selected as the matrices, each of the minimum numbers of branches corresponding to the lines being based on linear transformation matrices included in F-functions that are input to a corresponding data line in the extended Feistel structure.

TL;DR: In this article, a cryptographic processing unit divides and inputs constituent bits of data to be subjected to data processing to lines, and repeatedly performs a data converting operation using round functions on the data of the respective lines.

TL;DR: In this article, a data segment is encrypted to produce an encrypted data segment and auxiliary data is dispersed storage error encoded to produce a set of encoded auxiliary data slices, and a sequence of output slices is generated to obscure the encoded data slices.

TL;DR: In this article, an encryption processing apparatus includes a data retaining unit (11) configured to retain data to be processed, a mask retaining unit(21) configured with mask data to retain mask data, and a first linear transformation unit(B') configured to perform a linear transformation from the mask to first mask data.

TL;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.

TL;DR: In this paper, a sub-converter is provided in a data conversion apparatus for data encryption/decryption, where the sub converter converts data and transfers data that is nonlinear converted in a main converter or a key that is outputted from a key KL register 240 by switching between the data conversion function and data or key transfer function.

TL;DR: In this paper, a plurality of round processing parts (38) are provided each of which contains a nonlinear function part (304), and each non linear function part comprises: a first keydependent linear transformation part (341) which performs a linear transformation based on a subkey; a splitting part (342) which splits the output from the first key-dependent linear transform part into n pieces of subdata, respectively; a first nonlinear transform part (343) which nonlinearly transforms those subdata and a combining part (346) which combines the nonlinear transformed outputs

TL;DR: It is shown that using large S-boxes with good diffusion characteristics and replacing the permutation between rounds by an appropriate linear transformation is effective in improving the cipher security in relation to these two attacks.