Patent ID: 7197141

Claim:
An RSA cryptographic processing apparatus for a processor of an card system, the apparatus comprising, a memory for storing a data required for a modular operation in each allocated areas, sequentially supplying the data required for the modular operation by a control signal according to implementation of the modular operation, and storing the result value of the modular operation, an interfacing unit circuit for transmitting and receiving a control signal and the data required for the modular operation transmitted from the processor of the IC card system; a control register for storing information to control an operation mode of a cryptographic operation according to the control signal transmitted from the processor to the interfacing unit; an input register for previously reading and storing a data required for a modular multiplication or a modular exponentiation operation from the memory according to the information stored in the control register; a modular unit for performing the modular multiplication or modular exponentiation operation required for the cryptographic operation using an internal register by reading a value stored in the input register, wherein the modular unit includes a multiplying unit for multiplying two 32 bit operands for performing iterative operation; a subtracting unit for compensating the result value calculated by the modular unit; and control unit for storing the control signal transmitted from the processor of the IC card, loading the data from the memory to perform the modular operation according to the a control signal, providing the modular unit with the data through the input register, and generating a control signal required for the modular operation.