Chained Licenses

In PlayReady, licenses frequently occur in chains. A license chain consists of a root license and a leaf license. A leaf license may have multiple root licenses and a root license may have multiple leaves. A license chain exists for each pair. Each license in a license chain is expected to contain a valid set of rights. An action is permitted only if the right (to perform that action) is present in both the root and leaf licenses. For example, to play content, the AllowPlay right must be included in both licenses.

License chaining provides the flexibility of multiple licenses with the download performance of a single license. The content is directly bound to a leaf license. The leaf license is then bound to a root license. The root license is individually bound to each client.

In a license chain, it's recommended that only the root license contains the expiration policy. If the root license is the only expiring license in the synchronization list, only the root license needs to be renewed during license synchronization. This helps to improve performance during periodic updates.