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

A content recording apparatus, comprising:

• a processor configured to:
• obtain a content having a variable-length packet structure;
• generate encrypted data by encrypting the content;
• and
• record the encrypted data in a block unit having a fixed length in a recording medium, wherein
• the encrypted data includes only one invalidated region unnecessary for reproduction of the content,
• the processor is further configured to record a size of the only one invalidated region in the recording medium, and
• the block unit having the fixed length has a size n times or 1/n times as large as a size of a minimal structural unit when data is read from and the data is written to the recording medium, where n is an integer equal to or greater than 1,
• wherein the only one invalidated region is at a leading portion of the encrypted data, and
• the processor is further configured to record a size of the only one invalidated region in the recording medium.

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 only one invalidated region unnecessary for reproduction of the content, wherein the only one invalidated region is at a tail portion of the encrypted data;
• and
• recording a size of the only one invalidated region in the recording medium, wherein the block unit having the fixed length has a size n times or 1/n times as large as a size of a minimal structural unit when data is read from and data is written to the recording medium, where n is an integer equal to or greater than 1.

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

• 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 only one invalidated region unnecessary for reproduction of the content, wherein the only one invalidated region is at a leading portion of the encrypted data;
• and
• recording a size of the only one invalidated region in the recording medium, wherein the block unit having the fixed length has a size n times or 1/n times as large as a size of a minimal structural unit when data is read from and data is written to the recording medium, where n is an integer equal to or greater than 1.