Data encryption device, data decryption device, and data encryption/decryption device

摘要

Consider a case of implementing a circuit which performs both encryption and decryption according to a cipher that has the SPN construction. If a data transformation performed by a data transformation unit is an involution, i.e., a transformation which is equal to its own inverse, then the same data transformation unit can be commonly used for encryption and decryption. This enables a circuit which performs both encryption and decryption to be implemented without increases in circuit scale.