Intrusion-resilient public cloud auditing scheme with authenticator update

Abstract

Key-exposure resilient cloud storage auditing can create a secure cloud storage during before and after the key-exposure period. However, the malicious cloud server can still tamper with and even discard the client’s files which are uploaded during the key-exposure period without being detected. So as to cope with this problem, we propose an intrusion-resilient public cloud auditing scheme, in which auditing authenticators are updated periodically to prevent the malicious cloud from tampering with these files using the exposed key. In addition, our scheme is secure unless the client and TPA (Third Party Auditor) are compromised in the same time period. This is different from Yu et al.’s scheme proposed in TIFS 2017, which is not secure if the client and TPA are compromised in different periods. Finally, the scheme can protect the client’s file privacy, and prevent a curious TPA from recovering the file. The security analysis and the results of the experiment indicate that the security and performance of the scheme are acceptable.