SecAuth-SaaS: a hierarchical certificateless aggregate signature for secure collaborative SaaS authentication in cloud computing

Collaborative cloud business models enable a new dimension of business by giving option to the third party software vendors to deploy their software in the cloud for offering software as a service (SaaS) to the users. However, the secure provisioning of resources requires scalable architecture with efficient authentication for configuring the collaborative software services in the cloud. In this paper, we propose a novel hierarchical certificateless aggregate signature to provide a scalable authentication model for SaaS in cloud computing. Our proposed scheme is secure under the adaptive chosen-message attack in the random oracle model with the hardness assumption of Computational Diffie–Hellman (CDH) problem and Decisional Diffie–Hellman (DDH) problem. Furthermore, our proposed scheme is highly efficient regarding low overhead on computation and communication cost.