Seyed Mohammad Poursadeghi - M.SC student Data Security ,Taali University ,Qom ,Iran
Mohammad Ansari - M.Sc computer science , Tabari university ,Mazandaran , Iran
Mostafa Eftekhari - M.sc Electronic , Islamic Azad University south Tehran Branch , Mazandaran , Iran

Cloud computing has made lots of recent changes in people‘s lifestyle and workand that‘s because of its new numerous features. Although the security issue ofcloud computing is the subject of many of its customers and the biggest barrier forcloud computing to be widespread.In order to facilitate a conceptual understanding and to clarify the cloud‘s users tobe aware of security issues of this new paradigm we did a survey on the popularsecurity models and security gaps of cloud computing in general and also amongthe different layers of cloud services, cube conceptual model, and summarized themain security risks of cloud computing concluded from different organizations. Andfinally we presented some solving strategies.

Cloud Computing , Security models , Security strategy , Risk management