Science Publishing Group
Cloud is a latest computing paradigm. Cloud computing means storing and accessing data and programs over the internet instead of computer's hard disk. Cloud storage makes it easy to access the software, resources and data anytime anywhere when connected to the internet. Now-a-days, almost every organization is using cloud to store the data. There is a need to protect that data .Cloud data security goal aims at three main things: availability, confidentiality, and integrity. Cryptography is used to achieve confidentiality. Three types of algorithms are used in cryptography symmetric-key algorithms asymmetric-key algorithms and hashing.