tion</a></span></div>
<div class="block">Authenticate a received service request.

 <p>
 This method is called to transform the mechanism-specific request message acquired by calling getRequestMessage (on
 messageInfo) into the validated application message to be returned to the message processing runtime. If the received
 message is a (mechanism-specific) meta-message, the method implementation must attempt to transform the meta-message
 into a corresponding mechanism-specific response message, or to the v