To accelerate data transform processing such as ciphering/deciphering and data diffusion by configuring the device to perform a plurality of sub- transform processing in parallel.

The data transform device is provided with: a 1st sub-transform processing part (952a, 961) which, to two arbitrary input data A, B, applies a 1st non-linear transform to the input data A; outputs the exclusive OR of the 1st non-linearly transformed output data and the input data B as a 1st B-intermediate data, and outputs the input data B as a 1st A-intermediate data; and a 2nd sub-transform processing part (951, 952) which applies a 2nd non-linear transform to the 1st A-intermediate data; outputs the exclusive OR of the 2nd non-linearly transformed data and the above 1st B-intermediate data as a 2nd B-intermediate data, and outputs the 1st B-intermediate data as a 2nd A- intermediate data.