File fixity

<p>File fixity is a <a href="/facts/Digital_preservation/DouyNCS3">digital preservation</a> term referring to the property of a digital file being fixed, or unchanged. Fixity checking is the process of verifying that a digital object has not been altered or corrupted. During transfer, a repository may run a fixity check to ensure a transmitted file has not been altered en route. Within the repository, fixity checking is used to ensure that digital files have not been affected by <a href="/facts/Data_rot/Wx0yKo5N">data rot</a>, or other digital preservation dangers. By itself, fixity checking does not ensure the preservation of a digital file. Instead, it allows a repository to identify which corrupted files to replace with a clean copy from the producer or from a backup.
</p><p>In practice, a fixity check is most often accomplished by computing <a href="/facts/Checksum/AqxQ0I8g">checksum</a> or <a href="/facts/Cryptographic_hash_function/cuxkgbST">cryptographic hash function</a> values for a file and comparing them to a stored value or through <a href="/facts/Digital_signatures/tY7e2pnW">digital signatures</a>. File fixity figures prominently in <a href="/facts/Preservation_Metadata:_Implementation_Strategies_(PREMIS)/9BlDwT0R">Preservation Metadata: Implementation Strategies (PREMIS)</a>, the <a href="/facts/United_States_Government_Publishing_Office/U7CYW2fR">Government Printing Office</a>'s work on the Authenticity of Electronic Federal Government Publications, and fixity checking practices are used by a range of cultural heritage organizations.
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File fixity open-in-new

File fixity