Identity based and certificateless Auditing schemes for cloud Data integrity

Abstract

Cloud storage is a fundamental component of IT infrastructure for small businesses and enterprises. But the storage can be tampered either intentionally or unintentionally. So, the cloud client uses an auditing scheme called the Provable Data Possession (PDP) scheme to check the integrity of cloud data. The scheme audits the integrity without downloading the data blocks from the storage server. Securing the validity of the PDP scheme has been a challenge. Exposure of the audit key (auditing secret key) especially to the Cloud Service Provider (CSP) is a critical concern since the scheme fails to detect the data damage/loss as the validity of the scheme gets lost. It is also hard to find out if the exposure has already happened. The contributions of this work are within the scope of protecting the validity of the PDP scheme in the context of key-exposure. The existing PDP schemes tackle the key-exposure issue by altering/updating the value of the audit key over time. So, in any time period, a new data block or an updated data block is signed using the audit key of the corresponding period and the signature is called the authentication tag. Majority of these schemes use Public Key Infrastructure (PKI) and so experience the communication cost and the computational complexity of managing/verifying digital certificates. The computational complexity also increases while reviewing the integrity of the data blocks. Few schemes use Identity-Based Cryptography (IBC) and so overcome the overhead linked to certificates. But they protect the efficacy of auditing only in periods past to the period of the exposed key. It means that the risk of key-exposure lasts in future periods and in the period of the exposed key. Moreover, the third party Private Key Generator (PKG) who creates the audit key for the initial time newline