About notary function of intermediaries

As discussed during the last call I think a usefull function or role  
of intermedairy could be that of a notary. That is, it signs a  
payload received from party A and then sends it on to party B. By  
signing the payload the intermedairy confirms the payload as valid/ 
true, like a notary does in the real world. As such a document is  
regularly required by law it might be a usefull function in a  
messaging environment.

Regards,

Sander