NONLINEAR FUNCTION UNIT, CIPHERING DEVICE FOR STREAM CIPHER, DECIPHERING DEVICE, MAC GENERATING DEVICE

摘要

PROBLEM TO BE SOLVED: To reduce the scale of a packaged circuit while maintaining security.;SOLUTION: A nonlinear function unit which inputs bit data of a random number series and outputs converted bit data from a plurality of internal memories includes: computing units which compute the bit data of the input random number series and some of the internal memory data of the plurality of internal memories; and nonlinear substituting units which nonlinearly substitute the input bit data. The plurality of internal memories are annularly connected via the nonlinear substituting units and computing units, and the bit data of a random number series are input. Conversion matrices converting the elements of output data computed by the computing units are provided, and inverse conversion matrices corresponding to the conversion matrices are provided at the output terminal of the internal memories. Thus, the 32-bit input data are internally processed in 4-bit data unit.;COPYRIGHT: (C)2009,JPO&INPIT