ZIP version used for OPC

Tue Jan 29 23:20:28 CET 2019

Alfred,

"Public domain" is a copyright term and applies only to the document (the
APPNOTE.TXT document).  Compression algorithms can covered by patents and
thus subject to licenses.

As to the choice of ZIP, that was certainly made by Microsoft itself,
probably long before any current members of WG4 were involved with OOXML.
You might see if someone from the Office team who was around back then
might help you get the early history.

Rex and I were involved in the Ecma standardization process, although I
only joined the working group fairly late in the process.  What I remember
about ZIP from then is that at that point, PKWARE brought out a new
APPNOTE.TXT with every change and stopped providing access to old
versions.  Jean Paoli, or someone else in the Microsoft OOXML team, talked
to PKWARE and got them to agree to leave a copy of the version of
APPNOTE.TXT used in OOXML ( and indeed by the Open Document Format)
available.  I was involved in a related effort, to get copies of all old
versions available at the Library of Congress.  See
https://www.loc.gov/preservation/digital/formats/intro/specifications.shtml
.  As a result of these discussions, PKWARE made a decision to change its
strategy and does now make old versions  available on its website.  A
couple of those files are actually ones I retrieved from the Internet
Archive and sent to PKWARE.

[Aside:  The same page has links to the specs for the binary Office
formats.  That was requested by Jean Paoli as a step to make sure that
Microsoft was making those specs available somewhere trusted.]

I hope that helps a bit.

      Caroline

On Tue, Jan 29, 2019 at 4:48 PM Alfred Hellstern <
Alfred.Hellstern at microsoft.com> wrote:

> Thanks Murata-san. Are you saying that if WG4 were to make a normative
> reference to a newer version of the ZIP format, we’d be forcing
> implementers to pay licensing fees to PKWare?
>
>
>
> However, in the Wikipedia topic on PKWare, I find the following:
>
> PKZIP was the first program to use the new ZIP file format
> <https://en.wikipedia.org/wiki/ZIP_(file_format)>, which Katz developed
> in conjunction with Gary Conway and subsequently released into the public
> domain. PKWARE grew rapidly in its early years, fueled by enthusiasm from
> the bulletin board and shareware communities, along with steady business
> from large corporations who were eager to minimize the demands on their
> limited computing resources.[1]
> <https://en.wikipedia.org/wiki/PKWare#cite_note-wsjkatz-1> The .ZIP
> format proved so popular that it became the de facto standard for data
> compression and remains in use throughout the world after more than 30
> years.
>
> …
>
> In addition to its data compression and encryption products, PKWARE
> continues to maintain the .ZIP file format standard in the public domain.
> The company publishes an Application Note on the .ZIP file format,
> providing developers a general description and technical details of the
> .ZIP file storage specification.[7]
> <https://en.wikipedia.org/wiki/PKWare#cite_note-APP_Note-7> This
> Application Note ensures continued interoperability of the .ZIP file format
> for all users. (https://en.wikipedia.org/wiki/PKWare)
>
>
>
> If it’s public domain, doesn’t that mean “no licensing fees”?
>
>
>
> Do you or anyone have a bit more history on when and why ZIP was chosen,
> and how the licensing aspect was dealt with back then?
>
>
>
> Thanks
>
> ALfred
>
>
>
>
>
> *From:* MURATA Makoto <eb2m-mrt at asahi-net.or.jp>
> *Sent:* Thursday, January 24, 2019 8:39 PM
> *To:* Alfred Hellstern <Alfred.Hellstern at microsoft.com>
> *Cc:* SC 34 WG4 <e-SC34-WG4 at ecma-international.org>; caroline arms <
> caroline.arms at gmail.com>; Rex Jaeschke <rex at RexJaeschke.com>; Rich McLain
> <richmc at microsoft.com>
> *Subject:* Re: ZIP version used for OPC
>
>
>
> Alfred,
>
>
>
> First, I strongly think that digital signatures of OPC have
>
> to be significantly extended. XAdES EN, XML DSig 1.1, and
>
> SHA 256 are strongly required.  But WG4 has agreed not to
>
> do so in this revision.  One reason is that the revision of
>
> ISO 14533-2:2012 (XAdES Profile) has not been completed
>
> yet.  After the current revision of OPC is completed, I
>
> hope to start an amendment project for digital signatures.
>
>
>
> Second, it is not only OPC that uses DEFLATE and
>
> nothing else.  EPUB does the same thing.  I believe
>
> that other compression methods as documented in
>
> PKWARE Appnote require license fee to PKWARE.
>
>
>
> Regards,
>
> Makoto
>
>
>
> 2019年1月25日(金) 6:08 Alfred Hellstern <Alfred.Hellstern at microsoft.com>:
>
> Hello all,
>
> The Visual Studio team is looking into the OPC review, but in the meantime
> they were wondering about the ZIP compression format:
>
>
>
> “What is of more concern to me is no movement forward to support newer,
> better compression algorithms (i.e. based still on ZIP, which itself is
> limited to fairly light compression), and signature requirements to use
> only SHA1 which is no longer considered secure. Is the WG considering
> addressing these specifications while modernizing the OPC protocols? I
> appreciate that changing the container format is a daunting and perhaps
> irreconcilable task, but adding support for SHA256 or even dual-signing
> should be supported given that the signed XML specification that OPC uses
> has supported multiple signature algorithms for a very long time.”
>
>
>
> What’s our take on moving forward from the current ZIP version we’re
> using? I suspect this also has to do with the version of ZIP that Windows
> itself uses in its Compressed Folders feature (and see this blog post
> https://blogs.msdn.microsoft.com/oldnewthing/20180515-00/?p=98755
> <https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fblogs.msdn.microsoft.com%2Foldnewthing%2F20180515-00%2F%3Fp%3D98755&data=02%7C01%7CAlfred.Hellstern%40microsoft.com%7C47c250fcd9c34a3ff95908d6827f1807%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636839879712056531&sdata=lU5OLp1tfml84tYlAaasgSDePDLJdBqYYpNk9wzod7Y%3D&reserved=0>
>  indicating that’s not going to -ever- change.
>
>
>
> Alfred
>
>
>
> Click here
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>
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>
>
>
> --
>
>
> Praying for the victims of the Japan Tohoku earthquake
>
> Makoto
>
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