Faced with cost and regulatory considerations, many companies are outsourcing the storage of their data to third parties. Outsourcing data storage achieves economies of scale for the management of storage and avoids the large initial investment to set up data centers. Recently, many such online archival systems have emerged from within the research and industrial communities.
In storage outsourcing, a client sends data to a server, which is required by contract to provide persistent archives of the data. Since the server is not trusted and may misbehave, the client typically retains a small piece of metadata that is used to verify the authenticity of the data upon its retrieval. The problem is that by the time data is retrieved, it might be already too late to recover lost or damaged data. Current systems lack a basic guarantee: Proving data possession upon a user's request (usually before data retrieval).
In this presentation we introduce a model for provable data possession (PDP) that allows a client that has stored data at an untrusted server to verify that the server possesses the original data without retrieving it. We present provably-secure PDP schemes that have low (or even constant) overhead at the server and minimize network communication by transmitting a small, constant amount of data for every challenge/response.
This presentation is based on joint work with Giuseppe Ateniese, Randal
Burns, Joseph Herring, Lea Kissner, Zachary Peterson, and Dawn Song. A
complete description is available on the Cryptology ePrint archive at
Reza Curtmola is a post doctoral researcher in the Department of Computer Science at Purdue University. He received a PhD degree in Computer Science in 2007 and an MS degree in Security Informatics in 2003, both from The Johns Hopkins University. His research focuses on applied cryptography and security aspects of wireless networks.