Standard lifetime for Playready licence

Question

My drm-client (SmartTV) gets Playready licenses to decrypt video content. Sometimes the licence should be refreshed, but it's not clear when it should be done.

What is the standard or default expiration time of Playready licence? Does it exist?

Answer 1

The PlayReady License included in the response message from the DRM server contains a number of items, beyond the decryption key itself:

• key ID
• Content ID
• Set of rights and policies for the content key

Note also that a response can contain multiple licenses, each of which will have its own set of the above info - e.g. a response may contain different licenses for SD, HD and 4K streams for the content, and each stream may have different restrictions, for example 4K may not be allowed over HDMI.

The rights and policies associated with the content key include, again as an example, any HDMI restrictions, the security level the device must support etc. They also include the expiry information for the license which is typically an absolute date and time but there can also be policy rules to indicate that the license should expire after first play.

The rights and policies are set on the server side by the content owner or operator, so to answer your main question, the expiration can be different for different content depending on what the content owner or operator has configured.

From the client point of view, at a very high level, when a client or player detects that content is encrypted it checks if it has a valid key and if not it requests one. If the license has already been requested, is within its expiry time and is stored locally within the DRM's secure license storage, then the local DRM client will know it does not need to make a fresh license request.

For PlayReady specifically you can find quite good information in their online documentation - e.g. : https://learn.microsoft.com/en-us/playready/overview/license-and-policies