| Cloud Computing is a distributed computing paradigm which allows the users to access the services and shared resources hosted by the various service providers, to meet their services or resources requirements. In a multi-tenancy cloud computing environment, multiple virtual machines (VMs) are collocated on the same physical server. In such system, physical resources are transparently shared by the VMs belonging to multiple users.;Implementing a proper access control mechanism can lead us to prevent unauthorized or illegal access to cloud resources. In one hand, most of current access control techniques were originally designed for enterprise environments that do not consider the characteristics of cloud computing and multi-tenancy environments. On the other hand, a well-designed access control mechanism should impose less possible overhead to the cloud computing system and it should easily leverage with the existing cloud infrastructure. Today, VLANs and firewalls are example of techniques that provide access control for cloud environments. These techniques are definitely effective but we need complimentary techniques that fit cloud computing and prevent unauthorized access to the resources in the distributed system.;In this research project we propose CloudGuard, a system that implements a hypervisor-based access control mechanism. Based on the concept of security-in-depth, CloudGuard adds another layer of security to multi-tenancy cloud computing environments and prevents unauthorized and illegal access to the cloud resources. This security architecture can be simply implemented to hypervisor and provide scalable and more robust access control than existing network-based techniques.;Cloud computing also creates a suitable environment for easy targets, vulnerable and prone to sophisticated attacks. Also, due to the complexity of access and difficulty in monitoring all interconnection point between systems, applications and data sets, this can create new targets for intrusion. Undoubtedly, one of the most important security mechanisms in multi-tenancy cloud computing environment is access control. |
