Integrity Auditing of Outsourced Data

An increasing number of enterprises outsource their IT services to third parties who can offer these services for a much lower cost due to economy of scale. Quality of service is a major concern in outsourcing. In particular, query integrity, which means that query results returned by the service provider are both correct and complete, must be assured. Previous work requires clients to manage data locally to audit the results sent back by the server, or database engine to be modified for generating authenticated results. In this paper, we introduce a novel integrity audit mechanism that eliminating these costly requirements. In our approach, we insert a small amount of records into an outsourced database so that the integrity of the system can be effectively audited by analyzing the inserted records in the query results. We study both randomized and deterministic approaches for generating the inserted records, as how these records are generated has significant implications for storage and performance. Furthermore, we show that our method is provable secure, which means it can withstand any attacks by an adversary whose computation power is bounded. Our analytical and empirical results demonstrate the effectiveness of our method.