The present disclosure provides a method for
unicast transmission of encrypted
multicast content. An adapter receives the encrypted
multicast content along with
multicast content-related information (e.g., usage rules) and securely receives protection information from an entity associated with a DRM
server. The adapter generates a content key token containing at least one content
encryption key (CEK) and the with multicast content-related information (e.g., usage rules), using the protection information to protect
confidentiality and authenticity of at least part of the token. The adapter transmits the content key token to a device, enabling the device to request a DRM
license including the CEK from the DRM
server. The adapter then transmits the content encrypted with the CEK to the device in
unicast mode. The method enables secure conversion of multicast content to
unicast while maintaining end-to-end security between content access systems and DRM systems.