Objectives: Presently, cloud computing is efficiently sharing data and resources over the internet. It is composed of five crucial characteristics such as On-Demand self-service, Resource Pooling, Broad network access, Rapid elasticity and Measured Service. With these characteristics cloud computing is introduced with some open issues like, Security, Availability, Scalability, and Interoperability. Traditional techniques cannot keep cloud computing secure fully. In cloud deployment and delivery models, mostly arrives the privacy and security issues. Hence, cloud computing security and its techniques are hot topic for researchers. Methods: To deal with the current security issues in IT market, industries are developing their architectural models with having strong level of security to their data center. Findings: In this paper, cloud security and privacy issues are analyzed and cloud deployment model security is explored. Moreover, service models of cloud computing are also described with its security issues. The observation from this study is to consider Audit as the important parameter in presenting security solution that covers maximum parameters of security, which are taken into consideration from literature. Application/Improvements: This paper studied about the cloud security concerns and brings a new challenge to the cloud service provider and a parameter wise comparison of existing security solutions. Based on these comparison a new security model is proposed which describes user's security requirements.