Security concerns and risk at different levels in Cloud Computing

Cloud Computing has been emerged as a new consumption and delivery model of virtualization of high cost computing infrastructures for the web service based IT solutions. However, technical concern about security and privacy has been a key challenge for virtual centralization. In a cloud computing environment, multiple applications reside over networked hosts removing physical barriers between them. In this paper we aim to elaborate numerous security issues threatening web service based Cloud architecture and to analyze several existing and proposed solution models to mitigate the risks.