In today's era, cloud computing becomes the hottest topic due to its ability to reduce the cost associated with computing. Cloud computing provides the on-demand services like storage, servers, resources etc. to the users without physically acquiring them and the payment is according to pay per use. Since cloud provides the storage, reduces the managing cost and time for an organization to the user but security and confidentiality become one of the biggest obstacles in front of us. The major problem with cloud environment is the number of the user is uploading their data on cloud storage so sometimes due to lack of security, there may be chances of loss of confidentiality. To overcome these obstacles a third party is required to prevent data, data encryption, and integrity and control unauthorized access to data storage to the cloud. Cloud portability becomes critical in the situation of loss of confidentiality. To optimize better results we will review some paper and find the better results to remove the security barriers.