Content recording apparatus, content editing apparatus, content reproduction apparatus, content recording method, content editing method, and content reproduction method

A content editing apparatus which processes encrypted data recorded in a block unit having a fixed length in a recording medium,

• the encrypted data being an encrypted content having a variable-length packet structure,
• the content editing apparatus comprising:
• a determiner which determines part of the encrypted data as an invalidated region;
• and
• a recorder which records a size of the invalidated region in the recording medium.

A content reproduction apparatus which processes encrypted data recorded in a block unit having a fixed length in a recording medium,

• wherein the encrypted data is an encrypted content having a variable-length packet structure, and the encrypted data includes an invalidated region unnecessary for reproduction of the content,
• the recording medium records a size of the invalidated region, and
• the content reproduction apparatus comprises:
• a first reader which reads the encrypted data from the recording medium;
• a second reader which reads the size of the invalidated region from the recording medium;
• a decoder which decodes the encrypted data which has been read;
• and
• a reproducer which reproduces the content by extracting and outputting a remaining portion other than the invalidated region in data obtained by the decoder decoding the encrypted data, based on the size of the invalidated region which has been read.

A content recording method executed by a computer, the method comprising:

• obtaining a content having a variable-length packet structure;
• generating encrypted data by encrypting the content obtained;
• recording the encrypted data in a block unit having a fixed length in a recording medium, the encrypted data including an invalidated region unnecessary for reproduction of the content;
• and
• recording a size of the invalidated region in the recording medium.

A content editing method executed by a computer on encrypted data recorded in a block unit having a fixed length in a recording medium,

• the encrypted data being an encrypted content having a variable-length packet structure,
• the content editing method comprising:
• determining part of the encrypted data as an invalidated region;
• and
• recording a size of the invalidated region in the recording medium.

A content reproduction method executed by a computer on encrypted data recorded in a block unit having a fixed length in a recording medium,

• the encrypted data being an encrypted content having a variable-length packet structure, and the encrypted data including an invalidated region unnecessary for reproduction of the content,
• a size of the invalidated region is recorded in the recording medium, and
• the content reproduction method comprising:
• reading the encrypted data from the recording medium;
• reading the size of the invalidated region from the recording medium;
• decoding the encrypted data which has been read;
• and
• reproducing the content by extracting and outputting a remaining portion other than the invalidated region in the data obtained by the decoding based on the size of the invalidated region which has been read.