CipherData rationale

I think it would be useful to clarify the XML encryption spec with an example of
the different forms of CipherData. The definition of the CipherData element is
clearly articulated using XML schema, but XML Schema might not be clear to
everyone who will read the document.

Am I correct that CipherData would appear as one of the following:

<CipherData>
  <CipherValue>cryptobinary</CipherValue>
</CipherData>

or (with zero or more optional transforms)

<CipherData>
 <CipherReference URI="http://www.somewhere.com/cipherdata">
   <ds:Transform Algorithm=="http://www.w3.org/TR/2001/REC-xml-c14n-20010315">
 </CipherReference>
</CipherData>

An alternative might be CipherData which takes an optional URI attribute, and
optional transform elements
as well as the cryptobinary:

<CipherData>cryptobinary</CipherData>
or
<CipherData URI="http://www.somerwhere.com/cipherdata">
<ds:Transform Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315"/>
</CipherData>

This requires a statement which is more awkward in schema: "require URI for
cipherdata OR place cipherdata as cryptobinary within CipherData element"

Is the rationale that the first form makes for easier processing since the types
are clearly distinguished via elements at the expense of slightly more verbose
XML? I gather the first form is also more extensible.

Received on Tuesday, 29 May 2001 14:35:40 UTC