This architecture is a solu-To verify the performance of our solution, we have simulated our tion for ef???ciently authenticating operations on an outsourced ???leaudit service and storage service using two local IBM servers with system.two Intel Core 2 processors at 2.16 GHz and 500M RAM running Some recent work (Li et al., 2006; Ma et al., 2005; Xie et al.,Windows Server 2003 and 64-bit Redhat E