Patent ID: 8098388

Claim:
A content transmission device for transmitting content, whose copying is controlled, the content transmission device comprising: a processor configured to: perform an authentication procedure between the content transmission device and a content receiving device; generate first copy control information comprising at least four bits and indicating at least whether copying of the content is permitted; generate second copy control information comprising at least eight bits and including regions for identifying at least a multimedia type of the content, analog copy protection information for the content, and a picture size of the content in an output mode; generate a random number or pseudo-random number (nonce) used to create a content key to encrypt the content prior to transmitting the content from the content transmission device to the content receiving device; generate and transmit a packet to the content receiving device, the packet including a header including the first copy control information, the second copy control information, the generated nonce and a payload obtained by encrypting the content with the generated content key, wherein the header includes a field having a predetermined bit length of sixty four bits for transmitting the nonce, and the packet is transmitted in a form in which the second copy control information is embedded in the field for transmitting the nonce.