Introduction to Network Security, 2nd Edition

Chapter 7Cloud Security

Data and computing during the last decade are moving from the edge of the network into the center of the network known as cloud storage and cloud computing. This platform shift has reduced the infrastructure and management cost for end users, adding an important new dimension to computing that we have known for decades. Cloud computing, different from the model of computing centers decades ago, has four basic service models. They are the software-as-a-service model, the platform-as-a-service model, the infrastructure-as-a-service model, and the storage-as-a-service model. We discuss these models in detail in this chapter. We also discuss virtualization and other technologies that enable these infrastructures.

The decrease in infrastructure costs, on the other hand, has also been traded for increased security concerns. When carrying out computation and storing data on the clouds, the security of user data and computation lies in the control of the cloud providers. This is a significant amount of trust placed on a third party. We discuss the security concerns and describe solutions to the security problems for each of the cloud service models. We describe access controls in untrusted clouds using the proxy re-encryption schemes. We also discuss other security issues including proofs of storage and secure multiparty computations. Finally, we describe search over symmetric encryptions for the honest-but-curious clouds and the semi-honest-but-curious clouds. ...