The complexity of providing secure access, protecting critical data and end-user privacy in cloud data centre is leading to a demand for a new approach in network and data security. Recently, blockchain technology is being used in claims management to provide a decentralized and secure solution. The issue of security is crucial in the Virtual machine authorization in the cloud data centers. In the traditional approach of VM authorization, SSH key and IP address is given to the user to log into virtual machines. This opens much vulnerability as it might get spoofed or sniffed from the network, leading to accesses of private data to intruder. In this work, we propose a method which intends to aid in the security of the VM authorization using claims-based authorization system in conjunction with Blockchain based decentralized storage. Furthermore, the proposed system automates the process of launching a VM in OpenStack orchestration software.