Aiming　at　the　problem　of　the　cipher　key　delivery　in　secure　multicast,　a　transport　protocol　that　exploits　the　properties　of　logical　key　hierarchies　to　meet　the　requirements　of　reliability,　real-time　and　scalability　was　presented.　When　updated　keys　are　delivered,　they　are　assigned　to　different　weights　based　on　the　number　of　their　receivers,　and　the　different　redundancy　of　FEC　(forward　error　correction)　encoding　is　determined,　thus　the　keys　that　have　more　receivers　will　have　more　reliability.　The　performance　of　the　proposed　protocol　was　analyzed　and　simulated　using　independent　loss　model　and　burst　loss　model,　respectively.　The　result　shows　that　it　not　only　can　reduce　latency,　but　also　can　averagely　reduce　communication　overhead　by　30%　for　different　loss　rates.