Can a general KDM only limit the time instead of the device?

[niuniu]

I want to make a KDM (or any other way) that only limits the effective date (time period) of playback, and does not limit which projector in which cinema plays. Can this requirement be solved? In other words, it is a general KDM, which only limits the time, not the device.

[jdent02]

Don't think so. KDMs are always encrypted based on the public decryption certificate of the 'target device', and there's no universal version of that.

[Carsten]

The only solution is to issue multiple KDMs for all devices present/known in that cinema. That's also common in commercial/mainstream distribution. You book a title and plan to screen it on screen X, but you get KDMs for screens X,Y,Z. If you are after a 'longterm' license, this of course does not cover devices that may be installed in that cinema in the future. They may need to come back to you for additional KDMs then.

If you want to issue KDMs for hundreds of cinemas and send them automatically, DCP-o-matic can do it. But of course you need to skim every servers/projectors certificate from them before that.