| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cryptographic processing apparatus capable of making current analysis difficult, by suppressing expansion in the circuit scale of an encryption arithmetic operation circuit and generation of leakage current during operation. Ž<P>SOLUTION: A cryptographic processing apparatus includes: registers 106A, 107A; a round arithmetic operation block 111 configured to perform a round arithmetic operation in accordance with data stored in the registers; a logic arithmetic operation block 113 configured to perform an exclusive logic arithmetic operation between one of a register-stored value and a round key Kn and an operation result of the round arithmetic operation block; and a decode block 102, configured to decode binary data in units of the predetermined number of bits to convert the binary data into decode data, having a number of bits higher than the number of bits of the binary data. The decode block 102 is disposed to supply data propagated on signal wiring to a register-stored value or round key supply block and the round arithmetic operation block to the logic arithmetic operation block, in a state where binary data are decoded into units of the predetermined number of bits and are converted into decode data, having number of bits higher than the number of bits of the binary data. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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