Authorized Content Verification Method, Content Transmission/Reception System, Transmitter, and Receiver

A content transmission and reception system comprising a receiver which transmits a content request and a transmitter connected to the receiver over a network which attaches, to encrypted content, update information updated by the transmitter at a predetermined time and required to create a content key used for content encryption and decryption and transmits the update information with the encrypted content, in response to a content request from the receiver,

• wherein the receiver has
• a verification request instrument which transmits an authorization verification request created using an exchange key shared in advance with the transmitter and the update information received from the transmitter, and
• a verification result check instrument which determines that the encrypted content being received is authorized content if a message of acceptance is received from the transmitter, and
• the transmitter has
• a verification request acceptance instrument which receives the authorization verification request transmitted from the receiver,
• an update information verification instrument which checks whether the update information included in the received authorization verification request is predetermined update information, and
• a verification response instrument which creates the message of acceptance using the update information and the exchange key shared with the receiver and transmits the message of acceptance to the receiver if it is determined that the update information is the predetermined update information.

A transmitter used in a content transmission and reception system in which the transmitter connected on a network attaches, to encrypted content, update information updated by the transmitter at a predetermined time and required to create a content key used for content encryption and decryption and transmits the update information with the encrypted content, in response to a content request from a receiver, comprising:

• a verification request acceptance instrument which receives an authorization verification request created by the receiver using an exchange key shared in advance with the receiver and the update information received from the transmitter and transmitted from the receiver;
• an update information verification instrument which checks whether the update information included in the authorization verification request received from the receiver is predetermined update information;
• and
• a verification response instrument which creates a message of acceptance for determining whether the encrypted content being received by the receiver is authorized content, using the update information and the exchange key, and transmitting the message of acceptance to the receiver if it is determined that the update information is the predetermined update information.

A recording medium which is processable by a computer having a program recorded thereon for causing a computer to execute the verification request step of, by the receiver, transmitting the authorization verification request, the update information check step of, by the transmitter, checking whether the update information is the predetermined update information, the message-of-acceptance transmission step of, by the transmitter, creating the message of acceptance and transmitting the message of acceptance to the receiver, and the authorized content determination step of, by the receiver, verifying that the transmitter is an authorized transmitter if the message of acceptance is received from the transmitter,

• in the authorized content verification method in a content transmission and reception system in which a transmitter connected on a network attaches, to encrypted content, update information updated by the transmitter at a predetermined time and required to create a content key used for content encryption and decryption and transmits the update information with the encrypted content, in response to a content request from a receiver, comprising:
• a verification request step of, by the receiver, transmitting an authorization verification request including at least the update information received from the transmitter;
• an update information check step of, by the transmitter, checking whether the update information included in the authorization verification request received from the receiver is predetermined update information;
• a message-of-acceptance transmission step of, by the transmitter, creating a message of acceptance using the update information and an exchange key shared in advance between the transmitter and the receiver and transmitting the message of acceptance to the receiver, if it is determined that the update information is the predetermined update information;
• and
• an authorized content determination step of, by the receiver, determining that the encrypted content being received is authorized content if the receiver receives the message of acceptance from the transmitter.