Cloud computing emerges as a new computing paradigm which aims to provide reliable, customized and QoS guaranteed dynamic computing environments for endusers. However, adopting a cloud computing paradigm may have positive as well as negative effects on the data security of service consumers. In a cloud computing environment, data and the application is controlled by the service provider. This leads to a natural concern about data safety and also its protection from internal as well as external threats. The major issues in cloud computing is the security of data being stored on the provider's cloud and privacy while the data is being transmitted. This paper deals with the methods of providing security by data encryption and to ensure that unauthorized intruder can't access your file or data in cloud.