| 摘要 |
PROBLEM TO BE SOLVED: To perform traitor tracing on a reception device which receives simultaneous content distribution service.SOLUTION: An encryption device comprises: a code detection unit 122 which detects a predetermined code in compression-encoded content data; a data division unit 124 which divides the compression-encoded content data into common part data and block data including the code and synchronization information; a code change unit 125 which changes the code into another code to generate changed block data; a block part encryption unit 126 which encrypts the block data by a first encryption key and encrypts the changed block data by a second encryption key; a common part encryption unit 127 which encrypts the common part data by a common encryption key; an encrypted packet generation unit 128 which converts the respective pieces of encrypted data into packets, and sets encryption key identification information in the corresponding packets to generate pieces of encrypted packet data; and a packet composition unit 129 which combines the respective pieces of encrypted packet data to generate encrypted content data. |
