Determining the presence of an XML signature

When a recipient receives an XML document containing a signature -
perhaps
containing an envloped signature, how does the recipient know there
is an XML Signature in the content. Either the recipient can 

a. search for a <ds:Signature> element in the XML document
b. or know that there is a XML Signature through some other
   mechanism.

Which of the above two is the correct or prevalent model ?

Thanks.

Sekhar

Received on Thursday, 1 November 2001 18:20:46 UTC