NDSA:NDSA Digital Stewardship Glossary

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Term	Definition	Definition Source(s)
Archival original	Use instead "Received Version"
Authenticity	A mechanical characteristic of any digital object that reflects the degree of trustworthiness in the object, in that the supportive metadata accompanying the object makes it clear that the possessed object is what it purports to be.
Backup	Additional copies of a digital asset made to protect against loss due to unintended destruction or corruption of the primary set of digital assets.The essential attribute of a back-up copy is that the information it contains can be restored in the event that access to the master copy is lost.
Bag	A package of content that conforms to the BagIt Specification (specification available at http://www.digitalpreservation.gov/documents/bagitspec.pdf). Under the specification, a bag consists of a base directory containing a small amount of machine-readable text to help automate the content's receipt, storage and retrieval and a subdirectory that holds the content files. Sea also "Bagit Specification" and "Bagger."
Bagger	A graphical software application tool to produce a package of data files that conforms to the BagIt Specification.See also "Bagit Specification" and "Bag."
BagIt Specification	An Internet Engineering Task Force (IETF)Internet-Draft specification for a hierarchical file packaging format for the storage and transfer of arbitrary digital content. Specification available at http://www.digitalpreservation.gov/documents/bagitspec.pdf. See also "Bag" and "Bagger."
Best Edition	The edition of a work, published in the United States at any time before the date of deposit, that the Library of Congress determines to be most suitable for its purposes.
Bit Preservation	A baseline preservation approach that ensures the integrity of digital objects and associated metadata over time in their original form, even as the physical storage media which houses them evolves and changes. Also known as "bit preservation."
Canonical	Use instead "Preservation Copy"
Chain of Custody	A process used to maintain and document the chronological history of the handling, including the transfer of ownership, of any arbitrary digital file from its creation to a final state version. See also "provenance."
Checksum	An algorithmically-computed numeric value for a file or a set of files used to validate the state and content of the file for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and comparing it with the stored one. If the checksums match, the data was almost certainly not altered. See also "Fixity Check."
Derivative	A transformed version of an original source file, often called a "service," "access," "delivery," "viewing" or "output" file, used to facilitate access to or additional use of the content.