WSSE 3.0

WSSE implements WS-* which is standard for interoperability. Digital signature, Authentication/User Token, WSE 3.0 does -
Security easier, integration with WCF,
---------||------||--------> Client Server <--------||------||--------- 6 Turnkey scenarios scenarios 1.

        send encrypted message 
        send encrypted large key
      ---------||------||-------->
Client                                    Server
(Public Certificate)                       (private key)
large key                                    
      <--------||------||---------
         send user/password encrypted with large key

Use policy file to get it done
WCF - Shipped with Vista. WSSE 3.0 wire level interoperability with WCF.

-----------------------------------------
|Secure|Reliable (new)| Tx      |             |
-------------------------------
|Soap  (Message)                   |   WSDL   |
------------------------------------------
| XML/XSD (data)                                  |
------------------------------------------
| http    (transport)   | TCP |Custom(UDP) |
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With 3.0, the ASMX besides the basic services can be hosted as a service along with websire