Patent ID: 6408075
Filing Date: 2002-06-18
Classification: G06F,G06K,G06Q,G07F,H04L

Abstract:
An information processing equipment for performing square-and-multiply algorithm calculation, comprising:modular exponentiation means for performing a modular exponentiation using a square; modular multiplication means for performing a modular multiplication using an output of said modular exponentiation means and input data; and modular multiplication result selection means for passing a modular multiplication result to said modular exponentiation means as a number to be squared if a value of a bit of the cipher key is 1, and passing a modular exponentiation result to said modular exponentiation means as a number to be squared if the value of the bit of the cipher key is 0, wherein said modular exponentiation means and the modular multiplication means repetitively operates for all bits of the cipher key, and a number of operations of said modular exponentiation means and the modular multiplication means is independent of the cipher key value.