[BlueCop]

CENC is mp4. CENC (Common Encryption) is used on the DASH netflix streams. CENC enables them to distribute a single file with encrypted parts using one key. It allows them to use different DRM schemes to distribute that same key in different ways.

There is a lot of unencrypted data in the MP4 describing the encrypted parts. It also includes a KID(Key ID) so one can identify which key it was encrypted with.

I am looking for libraries to parse the mp4 into its boxes so I can try to interpret more of the information inside. Sometimes the actual content AES key is encrypted inside one of these mp4 boxes.