A TPA Based Efficient Non-Repudiation Scheme for Cloud Storage

摘要

One of differences between cloud storage and previous storage is that there is a financial contract between user and the cloud service provider (CSP). User pay for service in exchange for certain guarantees and the cloud is a liable entity. But some mechanisms need to ensure the liability of CSP. Some work use non-repudiation to realize it. Compared with these non-repudiation schemes, we use third party auditor not client to manage proofs and some metadata, which are security critical data in cloud security. It can provide a more security environment for these data. Against the big overhead in update process of current non-repudiation scheme, we propose three schemes to improve it.