Data　privacy　protection　is　crucial　to　cloud　computing　since　privacy　leakage　may　prevent　users　from　using　cloud　services.　To　ensure　data　privacy,　we　propose　PriGuarder,　a　novel　privacy-aware　access　control　method.　This　method　spans　the　three　stages　of　a　cloud　service,　i.e.,　user　registration,　data　creation,　and　data　access.　At　each　stage,　users　can　choose　two　modes　to　interact　with　the　cloud　service　provider,　i.e.,　direct　or　indirect.　With　the　indirect　mode,　an　attribute　fuzzy　grouping　scheme　is　introduced　to　ensure　user　identity　privacy　and　attribute　privacy　in　all　the　three　stages.　Furthermore,　exploiting　data　encryption　and　timestamp　techniques,　new　access　control　protocols　are　proposed　to　regulate　interactions　between　users　and　the　cloud　service　provider.　We　illustrate　the　use　of　our　method　in　the　context　of　Amazon　S3.　Theoretical　analysis　and　comprehensive　simulation　experiments　have　been　conducted,　which　demonstrate　the　efficacy　of　PriGuarder.