A provable storage scheme with fairness and retrieval

Nowadays, cloud storage provides some convenience for a user to store his files, which takes some threats to his files as well. At the same time, the cloud storage provider worries about being extorted by some malicious user. In this work, we study the problem that protects a cloud storage provider from being extorted by a malicious user and enables a user to retrieve his files from the cloud storage at any time. To solve this problem, we design a provable storage scheme with fairness and retrieval; it consists of three protocols which are Setup, Audit and File retrieval. In our scheme, we introduce a public auditor, and use the public auditor to audit the behaviors of the user and the cloud storage provider. Our theory analysis and experimental results demonstrate that our scheme is secure and feasible.