Cloud computing provide facilitates computing assets on demand by the use of service provider. In IT communications cloud computing is out sourcing by the use of the Internet and maintaining own hardware and software environment. It is there whenever you need it, as much as you need, and you pay as you go and only for what you use. Security is a prim concern in the use of cloud computing. In this paper, we have presented encryption based security algorithms for cloud computing. Data Sharing is an important functionality in cloud storage. We show how to securely share data. We describe new public key cryptosystems which produce constant size cipher text but the other encrypted files outside the set remain confidential.

Computing, Advance Encryption Standard, Dara Encryption Stancared, Key aggregate cryptography.

[1] Ronald L. Krutz, Russell Dean vines, “Cloud Security: A Comprehensive Guide to Secure Cloud Computing” Indianapolis, Ind. Wiley Publication, First Edition -2010,ISBN: 978-470-58987-8.
[2] Nicholas J. Daras, Michael Th. Rassias, “Computation Cryptography and network security, Springer Publication, First Edition – 2015,ISBN:978-3319182742
[3] Oded Goldreich, “Modern Cryptography Probabilistic Proofs and Pseudo-randomness” Springer Publication, 1999 Editio-1998, ISBN: 978-3540647669
[4] Peter Gutmann,“ Cryptographic Security Architecture”, Springer-verlag Publication, First Edition-2003, ISBN:978-0387953878.
[5] Maram Mohammed Falatah, Omar Abdullah Batarfi, “Cloud Scalability Considerations”, International Journal of Computer Science & Engineering Survey,Volume-05, Issue-04,Page No(1-19) August 2014.
[6] Zuzana Priscakova and Ivana Rabova, “Model of solution for data security in cloud computing”, International Journal of Computer Science, Engineering and Information Technology, Volume-03,Issue-03,Page no(1-18),June 2013.
[7] Anisaara Nadaph And Vikas Maral “Cloud Computing – Partitioning Algorithm and Load Balancing Algorithm” International Journal of Computer Science, Engineering and Information Technology,Volume-04, Issue-05,Page no(1-4) October 2014.
[8] Satish s Hottin and Mr. S. Pradeep,” "Efficient Secure Date Sharing In Cloud Storage Using Key-Aggregate Cryptosystems", International Journal of Engineering Development and Research, Volume-03, Issue-02, Page no (38-44), May 2015.
[9] Mithun V Mhatre1, Dr. M. Z. Shaikh, “ Key-Aggregate Cryptosystem for Scalable Data Sharing in Cloud Storage- A Review”, International Journal of Advanced Research in Computer Science and Software Engineering,Volume 5, Issue 7,Page no( 1-4)July 2015.
[10] G.Tzeng, “A Time:-Bound Cryptography key assignment scheme for access control in a hierarchy”, IEEE Trans. Knowledge and data engineering,Volume-14,Issue-01,Page no(182-188)Feb-2002.
[11] Cheng-Kang Chu, Sherman S. M. Chow, Wen-Guey Tzeng, Jianying Zhou, and Robert H. Deng, “Key-Aggregate Cryptography for scalable data sharing in cloud storage”, IEEE Transactions on parallel and distributed system,Volume-25,Issue-02,Page no(468-477),Feb-2014.
[12]Overview of Cryptography, www.garykessler.net/library/crypto.html,Aug 7, 2016.
[13] Encryption Algorithm www.storagecraft.com/blog/5-common-encryption-algorithms,31 July 2014
[14] Y. Sun and K. J. R. Liu, “Scalable Hierarchical Access Control in Secure Group Communications, ”org by-at The convention and exhibition center ,Hong Kong in Proceedings of the 23th IEEE International Conference on Computer Communications (INFOCOM’04). March 7-11, 2004.
[15] R. Curtmola, J. Garay, S. Kamara, R. Ostrovsky. “Searchable symmetric encryption: improved definitions and efficient constructions”,Proceedings of the 13th AC conference on Computer and Communications Security, ACM Press, pp. 79-88, 2006.
[16] R. Curtmola, J. Garay, S. Kamara, R. Ostrovsky. “Searchable symmetric encryption: improved definitions and efficient constructions”, In: Proceedings of the 13th AC conference on Computer and Communications Security, ACM Press, pp. 79-88, 2006.