1. 1. Z. Wan, J. Liu, and R. Deng, Hasbe: a hierarchical attribute based solution for flexible and scalable access control in cloud computing, IEEE Transactions on Information Forensics and Security, vol. 7, no. 2, pp. 743754, 201
   2. S. Yu, C. Wang, K. Ren, and W. Lou, Achieving secure, scalable, and engrained data access control in cloud computing, in Proceedings of the29thIEEE International Conference on Computer Communications. IEEE, 2010, pp. 19.
   3. S. Patil, P. Vhatkar, and J. Gajwani, Towards secure and depend- able storage services in cloud computing, International Journal of Innovative Research in Advanced Engineering, vol. 1, no. 9, pp. 5764, 2014.
   4. T. Pedersen, A threshold cryptosystem without a trusted party, in Proceedings of the 10th Annual International Conference on the Theory and Applications of Cryptographic Techniques. Springer,1991, pp. 522526.
   5. K.YangandX. Jia, Expressive, efficient and revocable data access control for multi authority cloud storage, IEEE Transactions on Parallel and Distributed Systems, vol. 25, no. 7, pp. 17351744, 2013.