Privacy Preserving Public Auditing for Regenerating Code-Based Cloud Storage

To prevent outsourced data in cloud storage against corruptions, adding fault tolerance to cloud storage together with data integrity checking and failure reparation becomes critical. Recently, regenerating codes have gain popularity due to their lower repair bandwidth while providing fault tolerance. Existing remote checking methods for regenerating-coded data only provide private auditing, required data owners to always stay online and handle auditing, as well as repairing, which is sometimes impractical. In this paper, we propose a public auditing scheme for the regenerating-code-based cloud storage. To solve the regenerating problem of failed authenticators in the absence of data owners, we introduce a proxy, which is privileged to regenerate the authenticators, to the traditional public auditing system model. Moreover, we design a novel public verifiable authenticator, which is generated by a couple of keys and can be regenerated using partial keys. our scheme can completely avoid data owners from online burden. In addition, we randomize the encode coefficients with a pseudorandom function to preserve data privacy. Analysis shows that our scheme is secure under random oracle model and experimental evaluation indicates that our scheme is highly efficient and can be feasibly integrated into the regenerating-code-based cloud storage.