Abstract: 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 (1) Symmetric-key algorithms (2) Asymmetric-key algorithms and (3) Hashing. Hashing algorithms ensure integrity of data. Cloud provides three types of services to its users: SaaS – enables users to run applications online through cloud computing techniques PaaS – enables the users to build their own cloud applications using supplier-specific tools and languages through cloud computing techniques.IaaS – enables the users to run any application on supplier’s cloud hardware. This paper discusses the types, service model, deployment methods, data security and privacy concerns in cloud.Abstract: 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...Show More