Can DCPoMatic generate KDMs etc. for DCPs made by other software

[rtX]

I have a DCP made by another DCP creation program. Assuming I have the film's private key (which I presume is the equivalent of the file DCPoMatic creates called metadata.xml (?)), and the public key of the server/projector is it possible for DCP0Matic to generate KDMs etc. for that film?

Many thanks.

[carl]

Hi, at the moment that's not quite supported as DCP-o-matic has no way for you to tell it the private key; that could be added though.

[rtX]

Thanks, Carl. Within the specifications of a what a DCP is, is the location of the private key specified? In DCP-o-Matic am I correct that the private key certificate is in the metadata.xml file in the directory immediately above the DCP directory itself? The reason I ask is that the facility that produced the (EasyDCP) DCP to which I refer in the original post does not know where EasyDCP keeps the private key and does not seem able to export it nor find it. I just found this out - so my initial question may in any event be redundant (as I don't seem to be able to get the private key). To be honest, I've already made a DCP of the same material using DCP-o-Matic but the attraction of using the other DCP is that their EasyDCP DCP has been QC'd already.

[carl]

The private key is what the KDM delivers. The advantage of that is that only the intended recipient can read the private key. The "official" way for you to get the private key would be for the Easy DCP facility to give you a "DKDM" which is a KDM targeted at your PC (rather than a projection system). You could then decrypt the KDM and get the private key and use it to generate further KDMs for the DCP.

In other words:

1. Easy DCP facility encrypts the "DCP private key" (which is a symmetric key) using your public key.
2. You receive the KDM and decrypt it using your private key which yields the DCP's private symmetric key.
3. You can then take the DCP private symmetric key and encrypt it with the public key of Alice's Cinema's Screen 1 playback server; this gives a KDM for Alice's Screen 1.
4. You send the KDM to Alice and her playback server uses its private key to decrypt the KDM so it has the DCP symmetric key and it can decrypt the DCP..

I expect Easy DCP does not allow the symmetric private key to be exported as it is a security risk; anyone that gets hold of it can decrypt your DCP. Also, I think some systems use different keys for the different parts of the DCP (DCP-o-matic currently uses the same key for all parts).

Does that answer your question?!
Best, Carl

[rtX]

Yes that answers the question brilliantly. Thank you for being so complete.