In this paper we address the more general problem of secure storage and retrieval of information (SSRI), and guarantee that also the process of storing the information is correct even when some of the servers fail. Our protocols achieve this while maintaining the (asymptotical) space optimality of the above methods. <P>
We also consider SSRI with the added requirement of confidentiality, by which no party except for the rightful owner of the information is able to learn anything about it. This is achieved through novel applications of cryptographic techniques, such as the distributed generation of receipts, distributed key management via threshold cryptography, and ``blinding.'' <P>
An interesting byproduct of our scheme is the construction of a secret sharing scheme with shorter shares size in the amortized sense. An immediate practical application of our work is a system for the secure deposit of sensitive data. We also extend SSRI to a ``proactive'' setting, where an adversary may corrupt all the servers during the lifetime of the system, but only a fraction during any given time interval.
Category / Keywords: Information security, information dispersal, distributed storage, threshold cryptography. Publication Info: Appeared in the THEORY OF CRYPTOGRAPHY LIBRARY and has been included in the ePrint Archive. Date: received December 10th, 1998. Contact author: garay at research bell-labs com Available formats: Postscript (PS) | Compressed Postscript (PS.GZ) | BibTeX Citation Discussion forum: Show discussion | Start new discussion