Internet　of　Things　(IoT)　cloud　provides　a　practical　and　scalable　solution　to　accommodate　the　data　management　in　large-scale　IoT　systems　by　migrating　the　data　storage　and　management　tasks　to　cloud　service　providers　(CSPs).　However,　there　also　exist　many　data　security　and　privacy　issues　that　must　be　well　addressed　in　order　to　allow　the　wide　adoption　of　the　approach.　To　protect　data　confidentiality,　attribute-based　cryptosystems　have　been　proposed　to　provide　fine-grained　access　control　over　encrypted　data　in　loT　cloud.　Unfortunately,　the　existing　attributed-based　solutions　are　still　insufficient　in　addressing　some　challenging　security　problems,　especially　when　dealing　with　compromised　or　leaked　user　secret　keys　due　to　different　reasons.　In　this　paper,　we　present　a　practical　attribute-based　access　control　system　for　loT　cloud　by　introducing　an　efficient　revocable　attribute-based　encryption　scheme　that　permits　the　data　owner　to　efficiently　manage　the　credentials　of　data　users.　Our　proposed　system　can　efficiently　deal　with　both　secret　key　revocation　for　corrupted　users　and　accidental　decryption　key　exposure　for　honest　users.　We　analyze　the　security　of　our　scheme　with　formal　proofs,　and　demonstrate　the　high　performance　of　the　proposed　system　via　experiments.　(C)　2019　Elsevier　B.V.　All　rights　reserved.