Resistance of S-Boxes against Algebraic Attacks

We develop several tools to derive linear independent multivariate equations from algebraic S-boxes. By applying them to maximally nonlinear power functions with the inverse exponents, Gold exponents, or Kasami exponents, we estimate their resistance against algebraic attacks. As a result, we show that S-boxes with Gold exponents have very weak resistance and S-boxes with Kasami exponents have slightly better resistance against algebraic attacks than those with the inverse exponents.