A key message can include a key-encryption-key (KEK) associated with a KeyDomainID and a KeyGroupID. A session description message can describe streaming media initialization parameters containing media stream information for one or more media streams. For each media stream, the media stream information can include an IP address and a data port. The session description message can further contain a linkage for binding the KEK to a corresponding one of the media streams. The linkage can include the KeyDomainID and KeyGroupID or can include an abstract representation of the KeyDomainID and KeyGroupID. During session initialization, the key-encryption-key (KEK) can be bound to the media streams using the linkage of the session description message. Each of the media streams can be secured using a traffic key conveyed to user equipment (UE) under protection of the key-encryption-key (KEK).