Split clouds: New security architecture for protecting user information from cloud insiders - Designs, implementation, and performance evaluations

Many government organizations are now considering their transitions to clouds. However, their concerns to known and unknown security risks in clouds are the major stumbling blocks against their transitions. This paper proposes new security architecture, Split Clouds, which protects the information stored in a cloud, while the architecture lets each organization hold direct security controls to their information, instead of leaving them to cloud providers. The core of the architecture consists of real-time lineage summaries, in-line security gateway and shadow auditor. By the combination of the three solutions, the architecture will prevent malicious activities performed even by the security administrators in the cloud providers. The essence of the architecture is in trading processor horsepower and network bandwidth for protecting information in clouds. Our performance evaluations showed that the overhead for security gateway and real-time lineage summary will be at most linear, while the overhead from the shadow auditor is in the square order, which can be mitigated by clustering. The proposed security architecture will be promising for clearing the ways for government organizations to adopt clouds.