| 摘要 |
PROBLEM TO BE SOLVED: To provide a modulator exponent device which can perform high-speed processing. SOLUTION: The modulator exponent circuit includes an I/F (interface) circuit 101 which is an interface to an external bus, an e register 102 which holds a key e, a Y register 103 which holds a multiplier Y for making Montgomery transformation, an N register 104 which holds a key N, a B2N register 105 which holds the value of 2B+N to be performed in computation of the Montgomery transformation, an X register 106 which holds plaintext X, an arithmetic circuit 107 for making computation for the purpose of encryption and decryption, a P register 108 which holds the result P of the computation, a power-residue control circuit 109 which is ought to play the role as a state machine in executing the modulator exponent, a Montgomery multiplication residue and residue control circuit 110 which plays the role as a state machine in executing Montgomery modulator exponent and remainder computation and an addition and subtraction control circuit 111 which performs the computation control of addition and subtraction.
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