Sustainability of Digital Formats: Planning for Library of Congress Collections

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Specifications for Digital Formats

Listed here are selected specifications made available for downloading by the Library of Congress with the permission of their owners and the intention of ensuring permanent access to the specifications for the digital preservation community and other users. Also listed are URLs for sources of freely downloadable specifications for digital formats from standards organizations. Citations to specifications for particular digital formats, with links if available online, will be found in individual Format Descriptions.

Microsoft Office Binary (doc, xls, ppt) File Formats

The formats and documents listed below are covered by the Microsoft Open Specification Promise (OSP). The documents below were provided by Microsoft Corporation in 2008 to the Library of Congress to be mounted for public access as demonstration of OSP. The specifications listed below date from 2008. Subsequent to 2008, Microsoft has updated the specifications for some of formats listed below. Updated specifications for the Microsoft Office Binary Formats are downloadable from Office File Formats Technical Documents. New versions of two of the other formats are available at Windows Technical Specifications. The formatting of the specification documents has changed a great deal since 2008; the substance of some specifications has also changed periodically as new features have been introduced in Microsoft software and required supporting representation in the binary formats. Note that not all application features introduced in and since Microsoft Office 2010 are supported in the binary formats.

Microsoft Word
  • Word 97-2007 Binary File Format (.doc) Specification
    • PDF []
Microsoft PowerPoint
  • PowerPoint 97-2007 Binary File Format (.ppt) Specification
    • PDF []
Microsoft Excel
  • Excel 97-2007 Binary File Format (.xls) Specification
    • PDF []
  • Excel 2007 Binary File Format (.xlsb) Specification
    • PDF []
Office Drawing
  • Office Drawing 97-2007 Binary Format Specification
    • PDF []
Supporting Technologies for Microsoft Office Binary File Formats
  • Windows Compound Binary File Format Specification
    • PDF []
  • Windows Metafile Format (.wmf) Specification
    • PDF []
  • Ink Serialized Format (ISF) Specification
    • PDF []

ZIP File Format, PKWARE

The documents listed below are versions of APPNOTE.TXT, the Application Note specification document for the ZIP file format from PKWARE. This selection by PKWARE of chronological versions covers the introduction of all significant features into the ZIP specification. An archive of Application Notes since version 4.5.0 (2001-11-01) is made available by PKWARE.

ZIP Application Notes
  • APPNOTE.TXT 1.0, 1990-03-15
    Initial ZIP format created by Phil Katz of PKWARE, Inc. Includes original 96-bit (triple 32-bit) password encryption storage definition.
    • TXT []
  • APPNOTE.TXT 2.0, 1993-02-01
    Introduces the Deflate data compression algorithm which becomes one of the most widely used compression algorithms.
    • TXT []
  • APPNOTE.TXT 4.0, 2000-11-01
    Introduces support for using digital signatures to verify data in a ZIP file and adds the fast Deflate64 data compression algorithm.
    • TXT []
  • APPNOTE.TXT 4.5, 2001-11-01
    Introduces support for storing more than 65535 files in a ZIP file and file sizes exceeding the previous 4 gigabyte limit.
    • TXT []
  • APPNOTE.TXT 5.2, 2003-07-16
    Introduces initial storage specification for adding stronger encryption using algorithms exceeding 128-bits based on passwords, digital certificates, or a combination of both simultaneously.
    • TXT []
  • APPNOTE.TXT 6.2.0, 2004-04-26
    Defines storage specification to support encrypting ZIP file metadata, such as file names, within the ZIP Central Directory.  Reference version for incorporating the ZIP format into Office Open XML File Format standard ECMA-376 (versions 1, 2, and 3) and ISO/IEC 29500 (versions published in 2008 and 2012).
    • TXT []
  • APPNOTE.TXT 6.2.2, 2006-01-06
    Documents final storage specification for adding stronger encryption using algorithms exceeding 128-bits using passwords, digital certificates, or a combination of both simultaneously.
    • TXT []
  • APPNOTE.TXT 6.3.0, 2006-09-29
    Documents support within ZIP files for using hash algorithms of SHA-256, SHA-384 and SHA-512; incorporates LZMA and PPMd data compression algorithms; support for Blowfish and Twofish data encryption algorithms; definition of UTF-8 international file name storage.
    • TXT []
  • APPNOTE.TXT 6.3.3, 2012-09-01
    Formatting changes to the document add conformance requirements and support easier referencing by other standards that incorporate the ZIP format.
    • TXT []

Other lists of freely downloadable specifications

These lists may include standards unrelated to digital formats.

Freely Available Standards from ISO
ECMA Standards
NISO Standards
OASIS Standards
W3C Technical Reports and Publications (including Recommendations)
ITU-T Recommendations

external link disclaimer icon     Inclusion of a specification in this list does not constitute the Library's endorsement of the digital format. View the Library of Congress statement regarding external links, endorsement, and other legal matters associated with its Web sites.

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Last Updated: 06/28/2023