Design & Implementation of Mutually Verifiable Billing System for Cloud Computing Environment

The ability to record and account for the cloud resources usage in a credible and verifiable way is a precursor to widespread cloud deployment and availability since usage information is potentially sensitive and must be verifiably accurate. In an attempt to expand Public Key Infrastructure (PKI) usage to a cloud computing environment to provide a secure and undeniable billing mechanism, we found that the frequent public key operations for fine-grained billing lead to excessive computation overhead or bottleneck of the billing system. To alleviate these limitations, we propose a PKI-based billing system, namely which is enhanced with the delegation technology to offload complex PKI operations from the thin clients to the cloud infrastructure. In addition, we introduce the “Cloud-Notary-Authority” concept to supervise billing to make it more objective and accepted by both cloud users and providers. The proposed scheme can provide non-repudiation and integrity of the cloud resource usage records by devising a cloud-notary-authority that generates binding information between a user and resource usage log and retains the information in its local storage for future accusation. This work has been undertaken within the KAIST Cloud-Testbed for Campus-wide Educational Cloud Services. According to the performance evaluation, the throughput of our billing transactions (223.4 transactions per second) is much higher than the throughput of the PKI-based billing transactions (which averages 61.5 transactions per second).