Cloud Computing offers centralized, virtualized and scalable computing resources like applications, storage, network and server on demand basis as required by its customers. It creates a one-stop platform for the provision of variety of services and products inclusive of both hardware and software. The third parties who maintain and manage this massive storage environment are collectively called as Cloud Service Providers (CSP). It is the responsibility of the CSP to protect the data from various threats, attacks and vulnerabilities which stay as the hurdles in securing and preserving the privacy of the customer’s data stored in the cloud. This work presents the survey of the various security mechanisms and principles followed by the leading CSP’s and the unique features of their security policies to register themselves unique among their competitors. Also, this paper provides a comparative analysis based on the security characteristics followed by the CSP. © 2016, International Journal of Pharmacy and Technology. All rights reserved.