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It's worth noting that the DCP format doesn't have a master key - each "reel" of an encrypted film has its own content key, which is decrypted by each DCP playe
by sprocket35 10y ago
It's worth noting that the DCP format doesn't have a master key - each "reel" of an encrypted film has its own content key, which is decrypted by each DCP player's private FIPS protected key combined with a public Key Delivery Message from the distributor.
So if the DCP was indeed cracked, it was either because they gained access to the FIPS module in a DCP playback server, or they gained access to the plaintext content keys where the KDMs are generated. If they have the server's private key, they will be able to decrypt every other film that they have a KDM for and we should expect to see more DCP releases.
- usrusr 10y ago> they will be able to decrypt every other film that they have a KDM for and we should expect to see more DCP releases. If you have individually encrypted copies, it would be stupid to not also individually watermark them on the content level. With a bit of targeted key invalidation, this could well be contained to a one time breach.
- tomerv 10y agoThere is just one encrypted copy, with one key. But that key has many copies, each encrypted with a different copy. The device takes its private key, and uses it to acquire the "master" key, which is then used to decrypt the media. Of course, every movie release has its own "master" key.
- sp332 10y agoEven AACS on bluray discs can have multiple different copies of some parts of the video to watermark different sets of device keys. I know footage from theaters can be watermarked too, so I'd be very surprised if this distribution method didn't also have some kind of identification.
- djsumdog 10y agoSo DCP players in cinemas have to have access to a network? (or someone has to get the key and move it over via USB stick or something like that?)