DRM (FairPlay) Implementation and Key Management on iOS
The article explains iOS FairPlay DRM implementation, detailing the encryption workflow, SPC/CKC exchange, and key terminology, and compares two key‑management methods—AVAssetResourceLoader and the newer AVContentKeySession—while covering usage scenarios such as on‑demand, pre‑warming, offline playback, persistable keys, and video downloading via AVAssetDownloadTask.