A segmentation method based on s-box

Abstract

The invention discloses a segmentation method based on S boxes, including the following content: For the DES algorithm: replace the S in the original algorithm with the S box of DESL 4 Or use S in the original algorithm 4 Replace all S-boxes in the original algorithm; for the CAST‑128 algorithm: remove the original algorithm's "cycle key" operation, and change both the "modulo plus key" and "modulo minus key" into "exclusive OR key" operations . Compared with the prior art, the positive effect of the present invention is: for the DES algorithm, after being replaced by the method of the present invention, its ability to resist differential analysis is obviously improved. For the CAST‑128 algorithm, by modifying the S-box and its use order, the new round function can resist the probability of 2 ‑7 Therefore, the modified algorithm can maintain its original ability to resist differential analysis, and at the same time resist side channel attacks.

Description

technical field [0001] The invention relates to a segmentation method based on S-box. Background technique [0002] Differential analysis was first proposed by Biham and Shamir in 1990, and it has been widely used in the analysis of symmetric cryptographic algorithms. Therefore, the security of cryptographic algorithms can be evaluated by studying the ability of cryptographic algorithms to resist differential analysis. The current research results show that the choice of S-box affects the probability of differential routing and the number of propagation rounds, which in turn affects its ability to resist differential analysis. Since the design details of the S-box used in the traditional DES algorithm have not been disclosed temporarily, it is possible to replace the S-box to improve its ability to resist differential analysis. [0003] Side-channel attack is a means for attackers to obtain keys by observing the running time, power consumption, and electromagnetic radiation...

AI Technical Summary

Problems solved by technology

[0003] Side channel attack is a means for attackers to obtain keys by observing the running time, power consumption and electromagnetic radiation of the algorithm, while the traditional CAST-128 algorithm cannot resist side channel attacks

The general method of resisting side-channel attacks is mainly by adding noise in the algorithm (such as by adding random delay in the algorithm operation), making it difficult for the attacker to identify the internal key information, but this resistance method is difficult to give provable security The result; at present, the most effective design method against side-channel attacks is to use a masking mechanism, which is provably safe, but the masking mechanism will greatly reduce the execution efficiency of the algorithm, making it difficult to use on small-scale embedded devices. impractical to run

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