A method and device for realizing block cipher FBC

Abstract

The invention discloses a method and a device for realizing a block cipher FBC. The encryption method comprises the following steps: 1) dividing plaintext data into a plurality of plaintext data groups, wherein each plaintext data group is n-bit plaintext data; 2) setting a master key k with the length of m bits, and generating a round key of the block cipher FBC according to the master key k; wherein m = Nn, and N is a natural number; setting a bit number s and a bit number t of cyclic left shift; setting a round of function F and a round number r; and 3) dividing each plaintext data group P into four w-bit words, and performing r-round encryption on the plaintext data group P by using a round key and a round function F according to a four-way double Feistel structure to obtain a ciphertext C. According to the method, under the condition that the degree of confusion between rows is ensured, the password implementation overhead is optimal.

Description

technical field [0001] The invention belongs to the technical field of information security, and in particular relates to a block cipher FBC realization method and a corresponding device. Background technique [0002] Block cipher is one of the mainstream cryptosystems. Because of its good scalability of plaintext information, sensitivity to insertion, no need for key synchronization and strong applicability, block ciphers are suitable as encryption standards. [0003] The overall structure adopted by the current block cipher can be divided into Feistel structure (such as CAST-256, DEAL, DFC, E2, etc.), SP network (such as Safer+, Serpent, etc.) and other cryptographic structures (such as Frog and HPC). Encryption and decryption are similar to an implementation advantage of Feistel-type ciphers, but it seems to be a bit slow in the diffusion of ciphers, for example, it takes two rounds to change every bit of the input. The network structure of SP is very clear, and S is ge...

AI Technical Summary

Problems solved by technology

However, the degree of confusion between the rows of the plaintext group is not enough. The usual practice is to perform a linear row transformation after the column transformation of the plaintext group, so as to ensure the degree of confusion between the rows, and correspondingly increase the cost of cipher implementation.

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