Cloud　computing　is　a　hot　topic　of　current　research,　and　identity-based　authentication　is　important　in　many　applications　scenarios　of　e-business　based　on　cloud　computing,　in　these　e-business　scenarios　users　should　prove　the　user＇s　legacy,　and　the　enterprise　needs　to　determine　whether　the　user　has　the　right　popedom,　so　this　paper　presents　a　identity-based　authentication　scheme　for　this　applications,　and　this　scheme　avoids　the　issues　how　to　revocation　public　key　certificate　and　the　escrow　problem　of　key,　and　then　the　security　of　the　scheme　is　analyzed,　at　last　the　communication　process　of　the　identity-based　authentication　scheme　is　described.