A communication system provides separate subscription keys for a non-subscriber version of a broadcast-multicast flow and a subscriber-only version of the flow, thereby controlling who may store or render the flow. In one embodiment, separate subscription keys may be assigned to a same broadcast-multicast flow. The communication system may then switch the keys used to encrypt the flow, or may use different keys to encrypt different copies of the flow, in order to allow at least non-subscribers to view one version of the flow and only subscribers to view another version of the flow. In another embodiment, the communication system may assign a group subscription key to a group of broadcast-multicast flows that is separate from the keys assigned to each individual flow. The group subscription key may then be used to encrypt a non-subscriber version of any broadcast-multicast flow in the group of broadcast-multicast flows.