US Patent 11595191 Encryption key management system and encryption key management method

A storage apparatus sends a request for a key encryption key to a key management server using a storage apparatus ID as a parameter, acquires the key encryption key, for which a request has been sent to the key management server, and its attribute information, and stores the key encryption key and its attribute information in a key encryption key list while eliminating the key encryption key that is duplicated. Then, in the order listed in the key encryption key list, decryption of the encryption key is attempted by the key encryption key stored in the key encryption key list, and the success or failure of the decryption of the encryption key is determined. When the decryption of the encryption key using the key encryption key fails, the decryption of the encryption key is attempted using a key encryption key, which has not been attempted yet, in the key encryption key list.