WordML, object binary data changes after re-saving the same docume

[David Portabella]

Hello,

I have a MsWord document, and I save it using the WordML language (.xml).
For each object (for example, an Equation object), WordML has a binary data
section.

If I open a document containing an equation object, and re-save it (without
changing that equation in any way), the binary data section of that equation
object changes.
(However, the equation looks the same if I re-open the document)
In example below, the "pkg:binaryData" data keeps changing, even if I did
not modify the equation at all.
Why is that?


I am writing a program that reads the MsWord document (.xml), and the
program cannot know whether an equation object is the same as the previous
version of the document, or not.
How to get around of it?

Many thanks,
DAvid Portabella

+++++++++++++++++++
<w:r>
<wbject w:dxaOrig="200" w:dyaOrig="200">
<v:shape ...
<o:OLEObject Type="Embed" ProgID="Equation.3" ShapeID="_x0000_i1025"
DrawAspect="Content" ObjectID="_1248701608" r:id="rId12"/>
</wbject>
</w:r>

<Relationship Id="rId12"
Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject" Target="embeddings/oleObject1.bin"/>

<pkgart pkg:name="/word/embeddings/oleObject1.bin"
pkg:contentType="application/vnd.openxmlformats-officedocument.oleObject">
<pkg:binaryData>
0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAAAAAABAAAAAQAAAAAAAAAA
EAAAAgAAAAEAAAD+////AAAAAAAAAAD/////////////////////////////////////////////
....
</pkg:binaryData>
</pkgart>
+++++++++++++++++++