Abstract: A Montgomery inverse calculation device includes a plurality of registers each storing a value of a variable, a modulus register storing a modulus, a multiplier performing multiplication on the modulus. A comparator compares the value of the variable stored in each of the registers with an output value of the multiplier and generates a plurality of control signals. A plurality of shifters shifts bits of a value of a variable stored in a corresponding register among the registers in response to at least one first control signal, and a quotient generation block calculates a quotient of mod 2m with respect to values output from some of the shifters in response to a second control signal. A calculation block calculates an updated value of an output value of each of the shifters using the quotient in response to at least one third control signal.

Abstract: A modular calculator and a method of performing a modular calculation are provided. The modular calculator includes a first register to receive and to store a first integer, a second register to receive and to store a second integer, a calculator connected to an output terminal of the first register and an output terminal of the second register, and a controller to determine an arithmetic operation of the calculator by referring to a sign of the first integer and a sign of the second integer and to control the calculator to perform the determined arithmetic operation on one of an addition and a subtraction of the first integer and the second integer and a modulus value.

Abstract: A radix-2k Montgomery multiplier including an input coefficient generation unit to receive a multiplier, a multiplicand, a modulus, a sum and a previous sum, to generate and to output a partial product and a multiple modulus by using at least one of the multiplier, the multiplicand, the modulus and the sum, and to divide and to output the received previous sum into units of k bits, an accumulator circuit to receive the partial product, the multiple modulus and k bits of the previous sum from the input coefficient generation unit, and to generate and to output a carry and a sum by summing the partial product, the multiple modulus and the previous sum, and a carry propagation adder (CPA) circuit to generate and to output an ultimate sum by using the carry and the sum.

Abstract: Provided are a modular multiplier apparatus in which a value of a long path carry (LPC) is predicted to reduce a critical path of an arithmetic operation of Montgomery modular multiplication, and a method of reducing the critical path of the arithmetic operation.

Abstract: Provided is a method of calculating a negative inverse of a modulus, wherein the negative inverse, which is an essential element in Montgomery multiplication, is quickly obtained. The method includes setting a modulus, defining P obtained by converting the modulus to a negative number, and defining S obtained by subtracting 1 from P, and calculating a negative inverse of the modulus by using P and S.

Abstract: An electronic apparatus and a control method of the electronic apparatus are provided. A user may perform data communication between the electronic apparatus and an external apparatus connected to the electronic apparatus by moving the external apparatus to move a connector or a dial switch of the electronic apparatus to easily manipulate the electronic apparatus.

Abstract: A device and method of performing functions with an external device, the function performing method including: performing a first function when an external device is connected to a connecting unit in a first position, and performing a second function, different from the first function, when the external device is connected to the connecting unit in a second position.