一种保护由电子电路执行的针对侧信道攻击的Rijndael型算法的方法，其中：在应用来自第一替换盒的非线性块替换操作之前，将用第一掩码掩蔽要加密或解密的每个数据块 ，然后在替代后被第二个掩模曝光; 替代框在应用非线性运算之前逐块重新计算，替换框的块的处理顺序被提交到随机排列; 并且替换盒的重新计算使用第二掩模以及第三和第四掩模，第三和第四掩模的和等于第一掩模。

The invention relates to a protection method, a Rijndael-type algorithm executed by an electronic circuit, against the side channel attacks, wherein: each block (t) data to be encrypted or decrypted is masked (31) a first mask (m) prior to application (33) of a nonlinear operation block by striking from a first substitution table (S '; S), then is unmasked (34) by a second mask (m' ) after substitution; the substitution table is recalculated (44, 45, 46, 47, 48, 24) block by block, before applying the nonlinear operation, the processing order of the blocks of the substitution table being subjected to a permutation random (φ); and the recalculation of the substitution table involves the second mask (m ') and the third (M1) and fourth (m2) masks, the sum of the third and fourth masks being equal to the first mask (m).