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

From: David Burdett <david.burdett@commerceone.com>
Date: Wed, 22 Sep 1999 20:36:52 -0700
Message-ID: <123B7EB05559D311B0D900A0C9EA3D762AD8DC@NEPTUNE>
To: Greg Whitehead <gwhitehead@signio.com>, "'DJ'" <jevans@differential.com>, "Winchel 'Todd' Vincent, III" <winchel@mindspring.com>, Andreas Siglreithmayr <andreas.siglreithmayr@ixos.de>, "W3c-Ietf-Xmldsig (E-mail)" <w3c-ietf-xmldsig@w3.org>
Cc: "IETF Trade (E-mail)" <ietf-trade@lists.eListX.com>
I agree ... but in IOTP the XML data can include an offer that says, for
example, "purchase a widget for $10". This offer can be expressed in XML
(with a style sheet if required), HTML or plain text. However the buyer
needs to be "presented" with the offer to decide whether or not to accept
it. The offer can also be signed for the usual reasons such as:
- tamper resistance
- to authenticate the creator

So really there's a mixture of wire protocol and human intepretation ...

David

-----Original Message-----
From: Greg Whitehead [mailto:gwhitehead@signio.com]
Sent: Wednesday, September 22, 1999 4:13 PM
To: 'DJ'; 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)?


Where XML is being used in the context of a wire protocol, and there is no
XSL style sheet used in the interpretation of the messages by the protocol
engine, it shouldn't be necessary to include any XSL in the signature.

In general, you need to look at the context in which signed data is being
interpreted and be sure that all of the elements critical to the
interpretation can be trusted (were signed or obtained securely from some
trusted source).

-Greg

-----Original Message-----
From: DJ [mailto:jevans@differential.com]
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:winchel@mindspring.com]
>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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Received on Wednesday, 22 September 1999 23:41:22 GMT

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