Subject: RE: How to sign several resources (XML and XSL)?

From: David Burdett <[email-masked]>
Date: Wed, 22 Sep 1999 20:36:50 -0700

... otherwise how do you know the context for the XML data?

You know the context because interpretation of the XML data is being done by
software from a presumably reliable source to do the interpretation that is
built according to a specification that describes the semantics of data 

... I now feel that we're getting very close to the topic of "trusted"
applications  and I'm not sure we want to go there ...

David

-----Original Message-----
From: DJ [mailto:[email-masked]]
Sent: Wednesday, September 22, 1999 3:49 PM
To: David Burdett; Winchel 'Todd' Vincent, III; Andreas Siglreithmayr;
W3c-Ietf-Xmldsig (E-mail)
Cc: IETF Trade (E-mail)
Subject: RE: How to sign several resources (XML and XSL)?

UWI.com has an XML implementation that signs the "presentation" (eg. the
XSL)
as well as the XML.  In their view, it is critically important to sign
both, otherwise
how do you know the context for the XML data?  

dj

At 02:45 PM 9/22/99 -0700, David Burdett wrote:
>Following on from this I'm wondering what people's views are on signing an
>XML document that is primarily an XML representation of a data structure
>that is defined in a specification that is widely and publically available.
>
>The XML document, in it's native form is readable but not easily
>understandable. A style sheet would make the document easier to understand
>but is not required since the semantics of the document are defined in the
>specification. However could use of a stylesheet then be construed as
>altering the meaning of the XML document as far as a recipient is
concerned.
>
>I ask since this is what IOTP effectively does, it signs several parts of a
>data structure (represented in XML) and then creates new data structures
>from the orginal that are also digitally signed and, using additional
>"endorsing" signatures, "binds" the new document back to the original.
>
>David
>
>-----Original Message-----
>From: Winchel 'Todd' Vincent, III [mailto:[email-masked]]
>Sent: Wednesday, September 22, 1999 1:43 AM
>To: Andreas Siglreithmayr; W3c-Ietf-Xmldsig (E-mail)
>Subject: Re: How to sign several resources (XML and XSL)?
>
>
>>
>> I think that if someone signs an XML-document, s/he would also have
>>to sign the corresponding XSL file.
>
>Andreas:
>
>Other people on this list hold the very same opinion.  Indeed, as an
>American lawyer, I believe there are very good legal reasons why *not*
>signing the stylesheet might just get and XML document thrown out of court
>if/when it were introduced into evidence.  Such a result would, of course,
>make the technology much less valuable.
>
>Thank you for your input.  I think having someone with a new and fresh
>perspective helps to shed light on the simplicity and logic of the notion.
>I wish others would see it so clearly.
>
>Todd
>
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---

From: DJ <[email-masked]>
Date: Thu, 23 Sep 1999 09:21:06 -0700

But to present legally binding evidence at a future date you may need to
present the signed XML, the presentation (signed XSL) and perhaps even
the application that displayed it (a signed copy of Netscape??? or perhaps
the UWI.com forms browser?)

DJ

---

From: Roger Collins <[email-masked]>
Date: Thu, 23 Sep 1999 13:16:30 -0400

Following that line of reasoning would have us include a signed copy of the
whole operating environment including the operating system and all running
processes.  A reasonable boundary for the things that should be signed by a
party are the things that the party has control over (the XML and XSL) under
normal circumstances (i.e., when you are not being "hacked" by the party).

Roger

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]]On Behalf Of DJ
Sent: Thursday, September 23, 1999 12:21 PM
To: David Burdett; Winchel 'Todd' Vincent, III; Andreas Siglreithmayr;
W3c-Ietf-Xmldsig (E-mail)
Cc: IETF Trade (E-mail)
Subject: RE: How to sign several resources (XML and XSL)?

DJ