Implicit parameters

["Nick Pope" <pope@secstan.com>]

Following on from the discussion at the last DSS meeting, views are
requested on use of implicit parmaters and other methods for controlling DSS
services other than providing each control parameter explicetly.

There seems to be several mechanisms that can be used with DSS:
1) The requirements document mentions use of paramaters being implicit by
the URL (see 3.5.9)
2) Application profiles can imply use of certain parameters,
3) Signature policies (as described by ETSI)can be used to imply certain
parameter values
4) WS Policies have also been suggested as a mechanism forimplying
parameters.

Are all these methods of implying parameters necessary?  If so in what
situations are each method most appropriate?  SHould guidance be included in
the DSS spec?

Nick