Abstract: The aim of the paper is to enhance the cloud security and improve the data efficiency in cloud outsourcing. As the secu-rity of the cloud data is an important issue in cloud outsourc-ing, proper algorithm is necessary. Here in this paper a mech-anism for the cloud security has been proposed. The mecha-nism propose two algorithm, one is based on machine learning and another is based on neural network. The machine learn-ing base algorithm is based on the KNN algorithm and the neural network technique is based on data fragmentation and hashing technology. Both of these algorithms are efficient to enhance the cloud security through encryption for cloud data in the cloud server.