Mask method and mask device for SM4 algorithm

Abstract

The invention discloses a mask method and a mask device for an SM4 algorithm. The mask method comprises the following steps: acquiring an inputted masked plain text, a random mask and round keys; carrying out a first round operation of a round function on the masked plain text, the random mask and a first round key in the round keys, to obtain a first round ciphertext and a first round mask; carrying out a second round operation of the round function on the first round ciphertext, the first round mask and a second round key in the round keys, to obtain a second round ciphertext and a second round mask, so as to realize N rounds of operation of the round function in turn; and carrying out an XOR operation an N round ciphertext and an N round mask outputted from the N round operation, wherein the operation result is taken as an output of the SM4 algorithm. Namely, except for the first round operation in the N rounds of operation of the round function, masks required for each round operation are all obtained by the output of the last round operation next to the current round operation, and therefore a demask on an intermediate value of the N rounds of operation is not required by adopting the technical solution disclosed by the invention, so that a resistance to an energy attack is realized.

Description

technical field [0001] The invention relates to the technical field of cryptographic algorithm hardware implementation, in particular to a masking method and device for an SM4 algorithm. Background technique [0002] The SM4 algorithm is a block cipher algorithm announced by the National Commercial Cryptography Management Office. It is currently the most widely used block cipher algorithm independently designed by China. This algorithm is gradually being applied in smart cards and USBKeys. Considering the problem of operational efficiency, it has basically passed way of hardware implementation. In applications such as smart cards and USBKeys, the encryption algorithm must not only ensure the security of the protocol and mathematical algorithms, but more importantly, ensure that the power consumption or electromagnetic information of the encryption circuit during operation in actual use will not be used by the bypass analysis method, resulting in security threaten. [0003]...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the above-mentioned technical problems, an embodiment of the present invention provides a masking method and device of the SM4 algorithm, which is used to solve the problem of energy leakage caused by real intermediate value information in the masking method that introduces a random mask in each round, The technical scheme is as follows:

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