An integrated circuit may implement a masked substitution box that includes substitution function components, a decoder, and a logic component. Each of the substitution function components may receive a same input value and a different mask value and may generate a respective output mask value based on the same input value and respective different mask value The decoder may receive an input mask value and generate a decoded output value that is based on the received input mask value. The logic component may select one of the output mask values from one of the substitution function components based on the decoded output value.