关键词: 云计算，云存储，数据安全，数据完整性

Abstract: Cloud storage services enable user to enjoy high-capacity and high-quality storage with less overhead, but it also brings many potential threats, for cxamplc, data intcgrality, data availability and so on. This paper proposed a new integrality checking algorithm. Follow the analysis, this new algorithm, based on hash tree and big integer operation, can check mass files integrality in less storage, compute and network resource. In addition, it also supports some data dynamic update.

Key words: Cloud computing,Cloud storage,Data security,Data integrality