A reduction in the size of encryption processing configuration applying generalized Feistel structures is achieved. The encryption processing configuration applies a generalized Feistel structure for dividing and inputting data into multiple lines, and repeatedly executing data transformation processing applying a round function on the data transferred to each line, and during the execution cycle of a matrix operation by a matrix operation executing unit for executing linear transformation processing applying a matrix on the data in a first line, an operation is executed on the matrix operation processing data from the initial cycle and data in a second line. This configuration enables a register to be used for both the storage of the data for the second line and the storage of the results of the matrix operation on the first line of data in progress, a reduction in the total number of registers, and thus a reduction in size.