Identity Management services are essential in cloud computing for authentication of users. Such services preserve the privacy of the users and at the same time provide interoperability to work on multiple domains or cross clouds. Security is the prevalent challenge to promote cloud computing currently. Multi located data storages in the cloud make it even worse. In this paper we propose an approach addressing such requirements, based on the use of high-level identity verification policies expressed in terms of identity attributes, zero knowledge proof protocols, fuzzy logic and semantic matching techniques. The paper describes the basic techniques we adopt and the architecture of a system developed based on these techniques, and details of experimental results. © Research India Publications.