An LSI includes a first decryptor which receives first encrypted key data, and decrypts the first encrypted key data using a first cryptographic key, thereby generating first decrypted key data, a second cryptographic key generator which generates a second cryptographic key based on a second ID, a second encryptor which encrypts the first decrypted key data using the second cryptographic key, thereby generating second encrypted key data, and a second decryptor which decrypts the second encrypted key data using the second cryptographic key, thereby generating second decrypted key data. At a time of key setting, the second encryptor stores the second encrypted key data in a storage unit. At a time of key usage, the second decryptor reads the second encrypted key data from the storage unit.