The Efficiency ,Technology and the Independence Study of the Database outsourcing Security Service

Clients who adopt data outsourcing services tend to store their data in the media provided by the services providers. While through data analysis, author found that there’re no reliable promises in data securities as the services providers could not assure that the outsourced information won’t be disclosed by some third parties. Such as natural disasters 、some emergencies or crimes committed by in-house staffs and so on. Which means that if the information is stored in clear text, the risk of that the data might be disclosed or interpolated will always exists. Therefore, author point out that only when data stored in the cipher text form and the process of encryption/ decryption is managed by the users could guarantee the data real security and privacy. So it comes to the study of “efficiency, technology and the independence” in database outsourcing services when the users have to encryption and decryption by themselves. Based on the research and analysis of the problem, this paper tries to driving the solution of implementation strategy and methods

Safe caching in a distributed file system for network attached storage

In a distributed file system built on network attached storage, client computers access data directly from shared storage, rather than submitting I/O requests through a server. Without a server marshaling access to data, if a computer fails or becomes isolated in a network partition while holding locks on cached data objects, those objects become inaccessible to other computers until a locking authority can guarantee that the lock holder will not again directly access these data. We describe a server that acts as the locking authority and implements a lease-based protocol for revoking access to data objects locked by an isolated or failed computer. When a lease expires, the server can be assured that the client no longer acts on locked data, and can safely redistribute locks to other clients. During normal operation, this protocol invokes no message overhead, and uses no memory and performs no computation at the locking authority. 1