A Dependable and Secure Authorisation Service in the Cloud

Abstract

Cloud-based exchange of sensitive data demands the enforcement of fine-grained and flexible access rights, that can be time-bounded and revoked at any time. In a setting that does not rely on trusted computing bases on the client side, these access control features require a trusted authorization service that mediates access control decisions. Using threshold cryptography, we present an implementation scheme for a distributed authorization service which improves reliability over a single service instance and limits the power and responsibility of single authorization service nodes.