摘要 |
There is provided the present invention to prevent illegal copying of recorded information and enable flexible management of contents, and further facilitate improvement of copy protection technology and the like. A key obtaining module (2) is recorded on a read-only information recording medium (1) to which a copy protection technology is applied. A reproducing module (3) safely obtains a media key unique to the key obtaining module (2) from the key obtaining module (2), generates a content key from the media key, and decrypts an encrypted content (4) using the content key and reproduces the content. In this case, while the key obtaining module (2) needs to be present on the information recording medium (1), the reproducing module (3) and the encrypted content (4) do not need to be present on the information recording medium (1) and may be present outside the information recording medium (1). |