Hi,
DRM costs money and involves licenses. As a result, it cannot be offered to CE users.
We do, however, have documents describing the DRM solution we deploy for our own SaaS, for that, see:
https://knowledge.kaltura.com/kaltura-universal-digital-rights-management-drm
and:
https://knowledge.kaltura.com/sites/default/files/DRM%20Technical%20Specifications.pdf
You could implement the same backend yourself, if you'd like, there will be a license cost of course and I will not be able to offer you support for it.
Alternatively, you could just use our SaaS instead of self hosting the platform. That is not free of course, however, you can go with the VPaaS pay as you go model. For VPaaS, see https://vpaas.kaltura.com/pricing.html
For info about other pricing programs of the SaaS model, please contact our sales department.