A novel based security architecture of cloud computing Cloud computing is considered as the future of IT organizations. In weigh against to conventional solutions where all type of computing services are controlled through any type of personnel controls, it transfers all computing resources to the centralized large data centers, so users can enjoy services in a large scale on demand. Chiefly small and medium-size organizations can manage their projects by using cloud-based services and also able to achieve productivity enhancement with limited budgets. But, apart from all of these benefits, it may not be fully trustworthy. Cloud Computing do not keep data on the user’s system, so there is a need of data security. The user pays progressively attention about data security due to this off-side storage of data on cloud computing. In order to retain confidentiality of data against un-trusted cloud service providers, There are so many approaches. All modern cloudservice providers solve this problem by encryption and decryption techniques. They all have their merits and demerits. In present thesis, the basic dilemma of cloud computing security is inspected. We have also proposed a survey of various models for cloud security. To ensure the data security in thecloud, we suggest an efficient, accessible and adaptable cryptography based scheme. In-depth security and enactment inspection proved the proposed scheme as greatly efficient and robust against spiteful data alteration outbreak. The proposed scheme achieves scalability as well as flexibility due to its hierarchical structure.