DEVICE FOR MODULAR MULTIPLICATION

摘要

PURPOSE: A device for a modular multiplication is provided to execute a modular multiplication at high speed by repeating a bit multiplication and executing a modular multiplication of data more than a specific bit, thereby reducing a circuit area of a modular multiplication device, and a reducing memory accessing times using a register for storing a mid-point. CONSTITUTION: A memory(160) stores data for executing a modular multiplication of information. A processor requests the modular multiplication and loads/uses the multiplication results from the memory(160). A register(230) receives data for a modular multiplication from the memory(160), stores the data, and stores a mid-point being generated during the modular multiplication. A modular circuit(240) repeats a bit multiplication calculation, executes a modular multiplication of data which are greater than a specific bit, and stores a mid-point in the register(230) and a result value in the memory(160). A reduction circuit(250) corrects the result value selectively in accordance with a comparison result of the result value and the modular value. A control circuit(220) outputs various kinds of control signals to the register(230), the modular circuit(240), and the reduction circuit(250), and controls the modular multiplication.