REGULAR CONTENT CHECK METHOD, CONTENT TRANSMISSION/RECEPTION SYSTEM, TRANSMITTER, AND RECEIVER

摘要

It has been impossible to detect spoofing and invalid content transmission to a receiver by using invalid device monitoring communication between a valid transmitter and a receiver. There is provided a system for transmitting update information required for creation of a content key used for encryption/decryption together with an encrypted content. The system employs a valid content check method including: a step (S323) in which the receiver (200) transmits a validity check request including update information received from the transmitter (100); an update information correlation step (S313) in which the transmitter (100) for correlating theupdate information contained in the received validity check request with predetermined update information; approval message transmission steps (S314, S315) used when the update information is matched with the predetermined information, for creating an approval message by using the update information and an exchange key shared between the transmitter (100) and the receiver (200) and transmitting the message; and a valid content judgment step (S325) in which the receiver (200) for deciding that the content is valid upon reception of the approval message.