ENCRYPTION PROCESSING DEVICE, AND ENCRYPTION PROCESSING METHOD AND PROGRAM

摘要

An encryption process excellent in security and highly resistant to various attacks is realized. An encryption processing device includes an encryption processing section configured to repeat a round operation on input data and generate output data, and a key scheduling section configured to output a round key to be applied in the round operation by the encryption processing section to the encryption processing section. The encryption processing section has an involution property in which a data conversion function E and an inverse function E -1 of the data conversion function E are executed sequentially, and executes the round operation in which a constant is applied once or more in only one of the function E and the inverse function E -1 . The constant is configured as a state that satisfies a condition that all of constituent elements of a state which is a result of a matrix operation with the linear conversion matrix which is applied in the linear conversion processing section at a position adjacent to the exclusive-OR section to which the constant is input are nonzero.