Cloud Computing - An Overview of Architectures, Security Threats and Their Solutions

World is connected by the large web of internet and everyday tremendous amount of data is generated across different transactions. Management, storage and processing of this huge amount of data over the ?internet cloud? has become the most frequently used buzzword in the technology space. As the data size increased so did the necessity to transfer it over a network which led to the development of 'Cloud Computing '. The cloud has taken the load away from local servers and hard drives to help tech companies make the data accessible from anywhere across the globe. It can, therefore, be viewed as an extensive data sharing platform made available to ensure that no data is lost due to space deficiency. This technology is extensively used in many areas of engineering to enhance the data storage ability of the system. The applications of cloud range from emails, photos, data backup, databases for various applications etc. However exposing critical data to a third party vendor for storage makes it vulnerable and insecure. In this paper, we discuss various threats associated with cloud computing systems and possible solutions for the same. We address the issues pertaining to data confidentiality, data integrity and availability. We review the existing cloud infrastructures, services and deployment models. This paper also investigates various optimized architectures for implementing energy efficient cloud systems.