Apparatus and method for modular multiplier

The present invention relates to a modular multiplication apparatus and method. In the present invention, it receives data from the outside, and generates the control signal using the received data. Then, using the generated control signal to select any one of the at least one functional unit to access the memory, to the selected functional unit allowed access to the memory. Next, the at least one stores the result in memory that occur during the during when performing the modular multiplication operation of a selected function added by word repeatedly performed. Then, the transmission performs the multiplication result to the outside. Thus, continuous word - may be during a base modular multiplication process, by directly controlling the memory that is embedded, remove a time delay due to the data input and output. Encryption, modular (MODULAR), operations, exponentiation, time delay, memory, interface