Biblio

Cloud computing is widely believed to be the future of computing. It has grown from being a promising idea to one of the fastest research and development paradigms of the computing industry. However, security and privacy concerns represent a significant hindrance to the widespread adoption of cloud computing services. Likewise, the attributes of the cloud such as multi-tenancy, dynamic supply chain, limited visibility of security controls and system complexity, have exacerbated the challenge of assessing cloud risks. In this paper, we conduct a real-world case study to validate the use of a supply chaininclusive risk assessment model in assessing the risks of a multicloud SaaS application. Using the components of the Cloud Supply Chain Cyber Risk Assessment (CSCCRA) model, we show how the model enables cloud service providers (CSPs) to identify critical suppliers, map their supply chain, identify weak security spots within the chain, and analyse the risk of the SaaS application, while also presenting the value of the risk in monetary terms. A key novelty of the CSCCRA model is that it caters for the complexities involved in the delivery of SaaS applications and adapts to the dynamic nature of the cloud, enabling CSPs to conduct risk assessments at a higher frequency, in response to a change in the supply chain.

The theoretical construct of a Trusted Third Party (TTP) has the potential to solve many security and privacy challenges. In particular, a TTP is an ideal way to achieve secure multiparty computation—a privacy-enhancing technique in which mutually distrusting participants jointly compute a function over their private inputs without revealing these inputs. Although there exist cryptographic protocols to achieve this, their performance often limits them to the two-party case, or to a small number of participants. However, many real-world applications involve thousands or tens of thousands of participants. Examples of this type of many-party application include privacy-preserving energy metering, location-based services, and mobile network roaming. Challenging the notion that a trustworthy TTP does not exist, recent research has shown how trusted hardware and remote attestation can be used to establish a sufficient level of assurance in a real system such that it can serve as a trustworthy remote entity (TRE). We explore the use of Intel SGX, the most recent and arguably most promising trusted hardware technology, as the basis for a TRE for many-party applications. Using privacy-preserving energy metering as a case study, we design and implement a prototype TRE using SGX, and compare its performance to a previous system based on the Trusted Platform Module (TPM). Our results show that even without specialized optimizations, SGX provides comparable performance to the optimized TPM system, and therefore has significant potential for large-scale many-party applications.

We present a new approach to authentication using Trusted Execution Environments (TEEs), by changing the location of authentication from a remote device (e.g. remote authentication server) to user device(s) that are TEE enabled. The authentication takes place locally on the user device and only the outcome is sent back to the remote device. Our approach uses existing features and capabilities of TEEs to enhance the security of user authentication. We reverse the way traditional authentication schemes work: instead of the user presenting their authentication data to a remote device, we request the remote device to send the stored authentication template (s) to the local device. Almost paradoxically, this enhances security of authentication data by supplying it only to a trusted device, and so enabling users to authenticate the intended remote entity. This addresses issues related with bad SSL certificates on local devices, DNS poisoning, and counteracts certain threats posed by the presence of malware. We present a protocol to implement such authentication system discussing its strengths and limitations, before identifying available technologies to implement the architecture.