An obfuscating apparatus creates a table for inputting the same number of arguments for multiplying and squaring operations, and sets the output values of the table so that the outputs may depend on the arguments. With regard to the squaring operations, there are added and tabulated adding operations using the arguments necessary only for the multiplications, so that the number of arguments is equal to that of the multiplication operations. The outputs depend on all the arguments, so that the presence or absence of the added arguments is unknown unlike the case in which dummy arguments that are not processed are added.