| 摘要 |
PROBLEM TO BE SOLVED: To provide an encrypted information reproduction method that can strongly prevent illegal use of contents information even in the case that a transmission stream is partially encrypted and to provide an encrypted information reproduction device. SOLUTION: All audio or image stream is encrypted at random in the unit of frames on the basis of a random number generated by a specific generation polynomial and the encrypted stream is transmitted. Since flag information or the like denoting which stream is encrypted or not is not provided in the stream, the security strength against the illegal use of contents can be much more enhanced than that of a conventional partial encryption method. In the case of reproduction, a random number is obtained by the generation polynomial known by only a legal user, the encrypted frame is identified and the transferred stream is reproduced. |
