At the time of playback, the content provider’s application initiates the content key request in FPS. This first
phase creates a server playback context (SPC). It prepares a graphic crypto-context on the client — to later
unwrap the content key and the initialization vector — that includes the session key, an anti-replay seed,
integrity verification, and server authentication elements. FPS protects the SPC with the content provider’s
RSA public key. A number of verifications are performed by FPS to check the content provider’s certificate
before exchanging encrypted media.