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POTSHARDS—A Secure, Recoverable, Long-Term Archival Storage System

Date

July 01, 2009

Author

Mark W. Storer, Kevin M. Greenan, Ethan L. Miller, and Kaladhar Voruganti.

POTSHARDS is an archival storage system that provides long-term recoverable security for data with very long lifetimes by using provably secure secret splitting.

Users are storing ever-increasing amounts of information digitally, driven by many factors including government regulations and the public’s desire to digitally record their personal histories. Unfortunately, many of the security mechanisms that modern systems rely upon, such as encryption, are poorly suited for storing data for indefinitely long periods of time; it is very difficult to manage keys and update cryptosystems to provide secrecy through encryption over periods of decades. Worse, an adversary who can compromise an archive need only wait for cryptanalysis techniques to catch up to the encryption algorithm used at the time of the compromise in order to obtain “secure” data. To address these concerns, we have developed POTSHARDS, an archival storage system that provides long-term security for data with very long lifetimes without using encryption. Secrecy is achieved by using unconditionally secure secret splitting and spreading the resulting shares across separately managed archives. Providing availability and data recovery in such a system can be difficult; thus, we use a new technique, approximate pointers, in conjunction with secure distributed RAID techniques to provide availability and reliability across independent archives. To validate our design, we developed a prototype POTSHARDS implementation. In addition to providing us with an experimental testbed, this prototype helped us to understand the design issues that must be addressed in order to maximize security.

In ACM Transactions on Storage (TOS), Vol. 5, No. 2, June 2009, Article No. 5

Resources

The author's version of the paper is attached to this posting. Please observe the following copyright:© ACM, 2009. This is the author’s version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Storage(TOS), Vol. 5, No. 2, June 2009, https://dl.acm.org/citation.cfm?doid=1534912.1534914

The definitive version of the paper can be found at: https://dl.acm.org/citation.cfm?doid=1534912.1534914.

storer2009potshards.pdf