A low -entropy mask leak protection method and its implementation system for protecting the SM4 password chip

Abstract

The invention discloses a low-entropy mask disclosure protection method for protecting an SM4 cipher chip, and a system implementing the method. The method comprises the following step: 1) a mask with a length of 16 bytes is selected and divided into four groups, each of which comprises four bytes, and each group of the mask Mi is divided into a quaternion (Mi0, Mi1, Mi2, and Mi3); 2) pre-calculation is carried out on an S box to obtain 16 novel S boxes, the 16 novel S boxes are recorded as Snews, and the 16 Snews are stored; 3) a round function carries out mask updating on data to be protected through the four groups of the masks obtained in Step 1), the masks are selected according to a determined order, and the mask updating is carried out on the data to be protected according to the Snew corresponding to the currently used mask; and 4) after the last round of the mask updating is completed, the mask used for the last round of the mask updating is removed from data obtained through the last round of the mask updating, so that an encrypted ciphertext value is obtained. The method and the system provided by the invention have the advantage that the physical safety of the SM4 cipher chip in an actual application scenario is ensured.

Description

technical field [0001] The invention relates to a leakage protection method for protecting an SM4 cryptographic chip and an implementation system thereof. The method can be used to protect the security of a typical SM4 cryptographic chip, so that it can effectively resist security threats brought by side channel cryptographic analysis. The advantage of the proposed method is to protect the security of the SM4 cryptographic chip without significantly increasing the implementation overhead of the SM4 cryptographic chip. In fact, effective control of mask overhead can be achieved by reducing mask information entropy. The invention belongs to the technical field of information security. Background technique [0002] As a typical encryption chip leakage protection method, masking eliminates the statistical dependence between the sensitive intermediate value and the energy leakage information of the encryption chip by using random numbers to randomize the sensitive intermediate v...

AI Technical Summary

Problems solved by technology

However, the implementation cost of the common masking method is high, which seriously affects the operating efficiency of the SM4 cryptographic chip

Images