In a system which attaches update information required to create a content key used for content encryption/decryption to encrypted content and transmits the encrypted content, there is used an authorized content verification method including a verification request step of, by a receiver, transmitting an authorization verification request including update information received from a transmitter, an update information check step of, by the transmitter, checking whether the update information included in the received authorization verification request is predetermined update information, a message-of-acceptance transmission step of creating a message of acceptance using the update information and an exchange key shared between the transmitter and the receiver and transmitting the message of acceptance if the update information matches the predetermined update information, and an authorized content determination step of, by the receiver, determining that content is authorized content on the basis of reception of the message of acceptance.