CALCULATION DEVICE AND CALCULATION METHOD

摘要

A calculation device and a calculation method that do not output information necessary for decryption or encryption to the outside and that execute the self-defense function when a false attack is made. A command monitoring unit (44) monitors the sequence of an input command. In the first sequence, the first-stage process key is calculated from a hardware key (Khd) and the calculated process key is written in a key storage unit (47). In the subsequent sequences, the next-stage process key is calculated from the process key stored in the key storage unit (47) and, when commands with predetermined contents are received in a predetermined order, a content key is calculated and is written in the key storage unit (47). The content key is used to decrypt cryptogram data, and the decrypted data is output from data output means (63). When a false attack is executed, initialization is performed using key data (Ksl) as fixed-value data (Kf) and input data (Ein) as fixed-value data (Df).