Due　to　the　computing　capability　limitation　of　the　Internet　of　things　devices　in　the　perception　layer,　the　traditional　security　solutions　are　difficult　to　be　used　directly.　How　to　design　a　new　lightweight,　secure　and　reliable　protocol　suitable　for　the　Internet　of　Things　application　environment,　and　realize　the　secure　transmission　of　information　among　many　sensing　checkpoints　is　an　urgent　problem　to　be　solved.　In　this　paper,　we　propose　a　decentralized　lightweight　authentication　key　protocol　based　on　the　combination　of　public　key　and　trusted　computing　technology,　which　is　used　to　establish　secure　communication　between　nodes　in　the　perception　layer.　The　various　attacks　that　the　protocol　may　suffer　are　analyzed,　and　the　formal　analysis　method　is　used　to　verify　the　security　of　the　protocol.　To　verify　the　validity　of　the　protocol,　the　computation　and　communication　cost　of　the　protocol　are　compared　with　the　existing　key　protocols.　And　the　results　show　that　the　protocol　achieved　the　promised　performance.　©　2021　IEEE.