Searchable　encryption　is　an　important　technique　for　public　cloud　storage　service　to　provide　user　data　confidentiality　protection　and　at　the　same　time　allow　users　performing　keyword　search　over　their　encrypted　data.　Previous　schemes　only　deal　with　exact　or　fuzzy　keyword　search　to　correct　some　spelling　errors.　In　this　paper,　we　propose　a　new　wildcard　searchable　encryption　system　to　support　wildcard　keyword　queries　which　has　several　highly　desirable　features.　First,　our　system　allows　multiple　keywords　search　in　which　any　queried　keyword　may　contain　zero,　one　or　two　wildcards,　and　a　wildcard　may　appear　in　any　position　of　a　keyword　and　represent　any　number　of　symbols.　Second,　it　supports　simultaneous　search　on　multiple　data　owner＇s　data　using　only　one　trapdoor.　Third,　it　provides　flexible　user　authorization　and　revocation　to　effectively　manage　search　and　decryption　privileges.　Fourth,　it　is　constructed　based　on　homomorphic　encryption　rather　than　Bloom　filter　and　hence　completely　eliminates　the　false　probability　caused　by　Bloom　filter.　Finally,　it　achieves　a　high　level　of　privacy　protection　since　matching　results　are　unknown　to　the　cloud　server　in　the　test　phase.　The　proposed　system　is　thoroughly　analyzed　and　is　proved　secure.　Extensive　experimental　results　indicate　that　our　system　is　efficient　compared　with　other　existing　wildcard　searchable　encryption　schemes　in　the　public　key　setting.　©　2008-2012　IEEE.