A framework for evaluating trust of service providers in cloud marketplaces

The Cloud Security Alliance (CSA) provides a framework for cloud platform providers that manages standardized self assessments regarding security controls. The framework as it stands does not allow consumers to specify and check their own requirements, nor does it contain any means for verifying the capabilities claimed by the providers. From a customer perspective, both these aspects are essential for evaluating the trustworthiness of cloud providers and for making an informed decision. We propose a novel concept for verifying the capabilities captured in the CSA's framework, plus a decision model that checks consumer requirements against the verification results. Our capability verification combines hard trust based on rigid validation with soft trust based on evidence about past behaviour. Elaborate formal methods are applied in both fields and combined into a single concept.