An encryption processing device, comprising: an encryption processing unit configured to divide and input data to be processed in data blocks of a configured bit size into a plurality of lines, and repeatedly execute data transformation processing applying a round function on the data transferred to each line; wherein the encryption processing unit includes an operation unit configured to generate transformed data regarding the data for a first line from the plurality of lines, perform an operation on the data from the first line and a different, second line regarding the generated transformed data, and repeatedly execute an operation to use the data obtained as a result as input data for a next round, and a register configured to store the operation results from the operation unit, and wherein the operation unit is configured to sequentially obtain the data from the register, performs an operation in the sequence the data was obtained, and store the results of which into the register, and wherein the operation unit includes a matrix operation executing unit configured to execute linear transformations applying a matrix to the data in the first line, and the matrix operation executing unit executes, when a first cycle of a matrix operation is executed, an operation on the data in the second line during the execution of a matrix operation on the data in the first line; and characterized in that the encryption processing unit is configured without an independent register for storing the data from the second line important for executing an operation on the data in the second line after the important operation cycle of the matrix operation on the data in the first line finishes, and to use a register for storing the results of the matrix operation in progress on the data in the first line as a register for storing the data from the second line. an encryption processing unit configured to divide and input data to be processed in data blocks of a configured bit size into a plurality of lines, and repeatedly execute data transformation processing applying a round function on the data transferred to each line; wherein the encryption processing unit includes an operation unit configured to generate transformed data regarding the data for a first line from the plurality of lines, perform an operation on the data from the first line and a different, second line regarding the generated transformed data, and repeatedly execute an operation to use the data obtained as a result as input data for a next round, and a register configured to store the operation results from the operation unit, and wherein the operation unit is configured to sequentially obtain the data from the register, performs an operation in the sequence the data was obtained, and store the results of which into the register, and wherein the operation unit includes a matrix operation executing unit configured to execute linear transformations applying a matrix to the data in the first line, and the matrix operation executing unit executes, when a first cycle of a matrix operation is executed, an operation on the data in the second line during the execution of a matrix operation on the data in the first line; and characterized in that the encryption processing unit is configured without an independent register for storing the data from the second line important for executing an operation on the data in the second line after the important operation cycle of the matrix operation on the data in the first line finishes, and to use a register for storing the results of the matrix operation in progress on the data in the first line as a register for storing the data from the second line.