Block encryption apparatus, block encryption method and program

Abstract

In block cipher based on generalized Feistel network, pseudorandomness and strong-pseudorandomness may be fulfilled efficiently. In encrypting a plaintext of kn-bit blocks, Feistel permutation is applied in terms of 2n bits as a unit, and then block-based permutation based on a binary de Bruijn graph with symmetrical type 2 branch coloring is applied. The Feistel permutation and the block-based permutation are grouped together to form a round. The round is repeatedly performed a preset number of times to output a ciphertext.

Description

Technical field [0001] [Records for related applications] [0002] The present invention claims the priority of Japanese Patent Application: Japanese Patent Application No. 2009-246307 (application on October 27, 2009), and the entire description of the application is cited and described in this specification. [0003] The present invention relates to a block encryption device, a block encryption method, and a program. In particular, it relates to a block encryption device, a block encryption method, and a program using Feistel replacement (Festel replacement). Background technique [0004] The so-called block encryption is a type of shared key encryption, which uses a key to encrypt plaintext of a certain block size. As a representative construction method of block encryption, there is a method using Feistel substitution. Feistel substitution is to divide a block into two unit blocks A and B, input one unit block A into a non-linear function with a key called a round function, and...

AI Technical Summary

Problems solved by technology

Here, Mix is ​​a linear transformation of kn bits, but since Mix does not have different inter-block influences under the permutation based on n-bit block units, it is not safe under any circumstances.

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