Fine-grained　access　control　become　a　research　spotlight　in　the　scenario　of　the　smart　home　with　Internet-of-Things　(IoTs).　However,　most　of　the　existing　works　could　only　realize　ciphertext　outsourcing　with　an　unchangeable　encryption　key　in　the　cloud.　That　is　because　the　trivial　solution　needs　great　communication　overhead.　To　overcome　this　challenge,　we　propose　an　updatable　encryption　scheme　named　SM9-UE　for　the　IoT　smart　home　scenario.　The　scheme　in　constructed　on　the　basis　of　SM9,　a　Chinese　official　cryptography　standard.　SM9-UE　realizes　secure　and　lightweight　ciphertext　updating　through　using　the　token　generated　by　the　data　owner,　which　is　information　independent　with　the　plaintext.　We　give　the　formal　security　definition　and　prove　it　to　be　IND-UPD　secure.　Theoretical　comparisons　demonstrate　that　our　scheme　is　efficient　in　terms　of　computation　and　storage.　Experimental　results　also　indicate　that　SM9-UE　can　be　practically　applied　to　IoT　smart　home.　©　2021,　ICST　Institute　for　Computer　Sciences,　Social　Informatics　and　Telecommunications　Engineering.