Japanese position on the introduction of XAdES to OPC.

[John Haug]

I suspect my position on this would be easily guessed, but I strongly disfavor updating OPC in a way that breaks backward compatibility.  Even putting aside my Microsoft hat representing the single largest installed base of implementations of OPC, whether that be Office or XPS (both the .xps file format and Windows print spool format which implement ECMA-388, which incorporates OPC by reference) or .NET Framework (System.IO.Packaging) or Windows Presentation Framework/XAML – and there are other implementers – I’d have to argue the point that where software has adopted digital signatures based on XMLDSig and gone further, the existing XAdES specifications are what has been adopted.  We’d do a disservice to current implementers and to users of many current documents to create a discontinuity in compatibility.

I believe we are getting too far down into the details of whatever work ETSI is doing now or may do in the future to revise XAdES.  There is risk I feel is inappropriate to take on in requiring use of a new, unpublished/unapproved proposed standard that has no adoption by industry while ignoring one that does have at least some industry adoption.  Regardless of considering which version to require, I don’t believe we need to or should mandate one version or another – let implementers decide what level of security they need for their application.  I assert that our interest from the perspective of 29500 is to provide requirements that improve interoperability among implementations of OPC that use XMLDSig and XAdES.  And I still believe we can do that with simple statements like we’ve looked at before, ones that just require this choice or that where XAdES provides options or leaves something as implementation-specific.  Both the new and existing versions of XAdES are backward-compatible extensions of XMLDSig, the fundamental underlying technology the use of which is an important choice to make for the standard, so the previous sentence should hold.

> As you know, Japanese XAdES experts are unhappy with the MS  implementation.
I think this is in reference to Office writing out SignaturePolicyIdentifier elements that are empty or use SignaturePolicyImplied.  Whether to allow that (which is legal XAdES) is a question we can take up along with the context of other related standards and implementations (e.g., ODF and MS-OFFCRYPTO make no statement on these elements).  Chris and I can raise those concerns with the development team here, but let’s leave any individual concerns with Office’s particular implementation choices separate from what we choose to specify in the standard.

John

From: eb2mmrt at gmail.com [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA Makoto
Sent: Tuesday, May 26, 2015 8:02 PM
To: SC34
Subject: Japanese position on the introduction of XAdES to OPC.

Dear colleagues,

This mail is to describe the Japanese position on the
introduction of XAdES to OPC.  Japan believes that the
ongoing revision of OPC (Open Packaging Conventions)
should use the first part of the new version of XAdES and
nothing else.

As we have discussed, there are two versions of XAdES.  An existing
version of XAdES is documented in ETSI technical specifications, while
a new and incompatible version is expected to become ENs (European
Standards) in one year.

The first version is already implemented by Microsoft Office.
This means that, if we introduce this version of XAdES to OPC
as a standard, we will run the risk of making the current implementation
by Microsoft non-conformant.  As you know, Japanese XAdES
experts are unhappy with the MS  implementation.

The latest version of XAdES consists of two specifications.
Apparently, Europe is committed to the first part.  The second part
appears to be an alibi for not abandoning some
features of the old version.

Moreover, the first part does not use any external files.  But the
second does.  This means that if such external files exist in an OPC
package, they look like orphans and will be thrown away by many
implementations including MS Office.  To avoid this problem, we will
have to introduce relationship types.   Japan does not think that the
second part has advantages significant enough for this additional effort.



Regards,
Makoto

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