In a MIME message, the base64 stuff carries the *content* (encoded
to get through hostile mail transports).
In the MD5 attribute, the base64 string is *generated from* the
content (by the author of the document), but the reader accessed
the content in the normal way, through a link.
My lame brain had just gotten this far :-)
Having got the content, the browser can then compute an MD5 on it
and confirm (because it is the same as the MD5 attribute on the
link) that the retrieved document is the very same one that the
document author was looking at.
<p>Here is my <a href="url" MD5("Chris")=3858f62230ac3c915f300c664312c63f>
last will and testament</a>.</p>
"Chris" being the MD5 key, presumably. Many thanks...I think we need
to document this pretty carefully.
<p>I give and bequeath all my worldly goods to Peter Flynn...</p>
:-)
///Peter