Cryptographic Processing apparatus, cryptographic processing method and storage medium storing cryptographic processing program for realizing high-speed cryptographic processing without impairing security

摘要

To provide a cryptographic processing apparatus that cryptographically processes input data using substitution table data to generate output data. A storing unit stores (2 &circ& N) sets of substitution data that each have a predetermined number of bits, where N is an integer no less than 2 A dividing unit divides the input data which is (NxM) bits long into M sets of N-bit subdata, where M is an integer no less than 2. A substituting unit receives an input that is any of: the M sets of N-bit subdata; and at least one set of N-bit input merged data generated by performing a merge process on the M sets of N-bit subdata, specifies one of the (2 &circ& N) sets of substitution data in the storing unit for each N bits of the input, and outputs the set of substitution data specified for each N bits of the input. A fixed conversion performing unit performs a plurality of different fixed conversions on at least one set of substitution data outputted from the substituting unit, to generate M sets of converted data that each have the predetermined number of bits. An output data generating unit generates the output data that is (NxM) bits long, based on the M sets of converted data generated by the fixed conversion performing means.