Editing ZIP (file format) (section)

=== Standardization ===
In April 2010, [[JTC 1|ISO/IEC JTC 1]] initiated a ballot to determine whether a project should be initiated to create an ISO/IEC International Standard format compatible with ZIP.<ref>{{Cite web |url=http://kikaku.itscj.ipsj.or.jp/sc34/open/1414.pdf |title=ISO/IEC JTC 1/SC 34 — Document Description and Processing Languages |date=2010-04-12 |access-date=10 May 2014 |archive-url=https://web.archive.org/web/20140512221201/http://kikaku.itscj.ipsj.or.jp/sc34/open/1414.pdf |archive-date=12 May 2014 |url-status=dead |df=dmy-all }}</ref> The proposed project, entitled ''Document Packaging'', envisaged a ZIP-compatible 'minimal compressed archive format' suitable for use with a number of existing standards including [[OpenDocument]], [[Office Open XML]] and [[EPUB]]. It would solve problems such as the need for a formal standard, the variety of extensions of ZIP, the undesirability of a technology used for [[Open Standard]]s potentially having proprietary extensions or "submarine" patents (i.e. which could surface unexpectedly), the need for better internationalization, and a desire not to actually fragment the technology further by purporting to provide an alternative specification to the PKWARE APPNOTE document. 

In 2015, ISO/IEC 21320-1 "Document Container File — Part 1: Core" was published which states that "Document container files are conforming Zip files", normatively referencing the PKWARE APPNOTE document. It requires the following main restrictions of the ZIP file format:<ref>{{cite web |publisher=ITTF |title=ISO/IEC 21320-1:2015 Document Container File — Part 1: Core |url=http://www.iso.org/iso/catalogue_detail.htm?csnumber=60101 |date=2015}}</ref>
* Files in ZIP archives may only be stored uncompressed, or using the "deflate" compression (i.e. compression method may contain the value "0" - stored or "8" - deflated). The patent on the core "deflate" compression method expired in late 2010.<ref>{{cite web |last1=Katz |first1=Phillip W. |title=String searcher, and compressor using same |url=https://patents.google.com/patent/US5051745 |date=24 September 1991}}</ref> 
* The encryption features are prohibited.
* The digital signature features (from SES) are prohibited.
* The "patched data" features (from PKPatchMaker) are prohibited.
* Archives may not span multiple volumes or be segmented.