As the practice of renting remote computing resources from a cloud computing platform becomes increasingly popular, the security of such systems is a subject of continued scrutiny. This thesis explores the current state of cloud computing security along with critical components of the cloud computing model. It identifies the need to trust a third party with sensitive information as a substantial obstacle for cloud computing customers. It then proposes a new model, Host-Obscure Computing, for a cloud computing service using secure enclaves and encryption that allows a customer to execute code remotely without exposing sensitive information, including program flow control logic. It presents a proof of concept for a secure cloud computing service using confidential computing technology, cryptography, and an emulator that runs in a secure memory space. It then provides an analysis of its effectiveness at reducing data exposure and its performance impact. Finally, it analyzes this model's advantages and its potential impact on the cloud computing industry. / Master of Science / The use of public cloud computing services continues to rise as a solution to many of the problems associated with on-premises data centers. Customers who would otherwise move to the cloud have resisted this change for security reasons. This research investigates what these security barriers are. Then, it proposes a novel model for a cloud computing service, referred to as Host-Obscure Computing, that is designed to mitigate these issues. Specifically, it addresses the need of a customer to share their program code and working data with the cloud provider. It outlines the development of a prototype implementation of this model. It then presents an analysis of this new service model from both a performance and security perspective. Finally, it suggests how the adoption of a service model similar to Host-Obscure Computing could improve the state of the cloud computing industry.

Industrial Control Systems (ICSs) manage critical infrastructures such as water treatment facilities, petroleum refineries, and power plants. ICSs are networked through Information Technology (IT) infrastructure for remote monitoring and control of physical processes. As ICSs integrate with IT infrastructure, IT vulnerabilities are carried over to the ICS environment. Previously proposed process controller security architectures maintain safe and stable plant operation even in the presence of attacks that exploit ICS vulnerabilities. Security architectures are process control system-level solutions that leverage isolated and trusted hardware (secure enclaves) for ICS security. Upon detecting an intrusion, the secure enclave switches control of the physical process to a high assurance controller, making a fail-safe plant operation. The process control loop components have an average lifespan of several decades. During this time, electromechanical components of process control loop may undergo aging that alters their characteristics and affects control loop performance. To deal with component aging and to improve control algorithm flexibility, updates to control loop parameters are required. Plant model, process control loop system specifications, and control algorithm-based security mechanisms at the secure enclave require parameter updates. ICSs have hundreds of process control components that may need be installed in hazardous environments and distributed across hundreds of square kilometers. Updating each component physically may lead to accidents, expensive travel, and increased downtime. Some ICS have allowable downtime of only 5 minutes per year. Hence, remote updates are desirable. A proposed dedicated and isolated hardware module at the secure enclave provides authentication of the update and ensures safe storage in a non-volatile memory. A protocol designed for update transmission through an untrusted ICS network provides resilience against network integrity attacks such as replay attacks. Encryption and authentication of the updates maintain integrity and confidentiality. During the normal plant operation, the hardware module is invisible to the other modules of the process control loop. The proposed solution is implemented on Xilinx Zynq-7000 programmable System-on-Chip to provide secure enclave updates. / Master of Science