Computer Security – ESORICS 2009

Volume 5789 of the series Lecture Notes in Computer Science pp 136-151

Authentic Time-Stamps for Archival Storage

  • Alina OpreaAffiliated withRSA Laboratories
  • , Kevin D. BowersAffiliated withRSA Laboratories

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We study the problem of authenticating the content and creation time of documents generated by an organization and retained in archival storage. Recent regulations (e.g., the Sarbanes-Oxley act and the Securities and Exchange Commission rule) mandate secure retention of important business records for several years. We provide a mechanism to authenticate bulk repositories of archived documents. In our approach, a space efficient local data structure encapsulates a full document repository in a short (e.g., 32-byte) digest. Periodically registered with a trusted party, these commitments enable compact proofs of both document creation time and content integrity. The data structure, an append-only persistent authenticated dictionary, allows for efficient proofs of existence and non-existence, improving on state-of-the-art techniques. We confirm through an experimental evaluation with the Enron email corpus its feasibility in practice.


time-stamping regulatory compliance archival storage authenticated data structures