Proxy Provable Data Possession with Key-exposure Resilient

More and more clients would like to store their data to public cloud server along with the rapid development of cloud storage.To check the integrity of remote data,researchers proposed provable data possession(PDP).In some cases,the client will be restricted to access the Internet,such as on the ocean-going vessel,participating in some classified projects.It has to delegate the remote data possession checking task to some proxy.However,in proxy PDP,once the client’s private key is exposed,auditing schemes would inevitably become unable to work.To solve these problems,the proposed scheme combines key-insulated with proxy PDP,and introduces a physically-secure but computationally-limited helper into the system model.The helper generates an update message in each time period and then sends it to the client to help the client calculate the signing key for the current time peroid.In this scheme,adversaries cannot forge user-generated authenticators during the time period when the key is not leaked.Security analysis and performance analysis show that the proposed scheme is secure and efficient.