P.S.S.N.N. Sindura, and B.RanjithKumar. “Anonymous Authentication and Revocable Data Access Control of Data Stored in Clouds”. International Journal of Computer Engineering in Research Trends, vol. 2, no. 10, Oct. 2015, pp. 857-60, https://www.ijcert.org/index.php/ijcert/article/view/261.