Cloud Computing may be a way of making the businesses more efficient. It enables to lower the cost of I.T. functions of the business and enables the business managers to focus on the core business. What it does is to shift the information technology function of the business to a remote service provider about whom we may not have any information. The concept of shifting computing to a shared service provider is not new. What is new is that the cost of cloud computing is falling so dramatically, that considering outsourcing to the cloud is no longer rare. In an era of tight budgets, the opportunity to make financial savings means, that the cloud computing looks especially attractive. However data security becomes more and more important in cloud computing as the data is hosted on an unknown remote computer and all the transactions have to be made to this computer. This paper analyses the basic problem of data security in cloud computing. Data security requirements of cloud computing were identified and a data security model is proposed through the analysis of HDFS architecture under the framework of cloud computing.

Keywords: Cloud Computing, HDFS, Data Security, Security Model