Cloud computing is an Internet-based computing model which provides several resources through Cloud Service Providers
Cloud computing is an Internet-based computing model which provides several resources through Cloud Service Providers (CSP) to Cloud Users (CU) on demand basis without buying the underlying infrastructure and follows pay-per-use basis. It supports virtualization of physical resources in order to improve efficiency and accomplishment of multiple tasks at the same time. Cloud Computing Environment (CCE) provides several deployment models to represent several categories of cloud owned by organization or institutes. However, CCE provide resources to Cloud Users through several services like PaaS, SaaS, IaaS. Cloud Computing is a notion based on the concept of summing up physical resources and displaying them as an unacknowledged resource. It is a model for producing resources, for sorting out applications, and for manifesto-independent user access to services. Cloud can come in different types, and the services and the applications that possibly run on clouds may or may not be provided by a cloud service provider. There are two unique group of models namely deployment models and service models. Service models consists of IaaS , SaaS, PaaS . The Deployment or deployment model consists of Public Cloud, Private Cloud, Hybrid Cloud, Community Cloud .Cloud Computing has lots of distinct properties that make it very important. privacy seems to be an unique concern in cloud .Various types of service models under cloud computing facilitate various levels of privacy services. We will get the minimum security in IaaS (Infastructure as a Service) and most with a SaaS provider. In this paper, we will focus upon the reviewing and understanding cloud security issues by proposing crypto algorithms and effective measures so as to ensure the data security in cloud. Along with this, we will elucidate a bit more about some security aspects of cryptography by showcasing some privacy issues of current cloud computing surroundings.