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The Library of Congress > Digital Preservation > News Archive > ACE Trumps Digital Integrity Threats

February 26, 2009 -- How does an institution know — for sure — that the integrity of its digital collections is secure? A host of threats are present, after all, from hackers to human error to hardware failure.

Audit Control Environment logo

The Audit Control Environment (ACE)

The University of Maryland has released the Audit Control Environment (ACE) to help archives and libraries manage the integrity of their holdings.

ACE continuously monitors cryptographic representations of digital objects and provides a way for independent third-party auditors to certify the integrity of any object.

The program has two components. The Audit Manager software is installed locally at an archive to monitor collections. It in turn communicates with another piece of software, the remotely stored Integrity Management Service, to compare and validate details about digital objects.

Periodically, ACE will audit collections and generate a report that identifies any missing or damaged files. Detailed logs are kept of any changes that occur to a collection.

After installation, archivists and librarians can configure the software through a web interface. The interface provides control over the files or collections for monitoring, and also enables the user to select other options.

The Chronopolis project is currently using ACE to monitor its holdings integrity. Software has been installed by three of the Chronopolis partners, the University of California, San Diego, San Diego Supercomputer Center (external link), the University of Maryland's Institute for Advanced Computer Studies (external link), and the National Center for Atmospheric Research (external link). These installations monitor files stored at each node and supply data to a project portal. Over a million files per day are audited on a regular basis.

More information detailing the ACE integrity mechanism and a download of the Audit Manager software is available at (external link).