Asynchronous Profile (request for comments)

[Andreas Kuehne <kuehne@klup.de>]

Hello, TC !

I like to collect some opinions regarding the way to asynch request 
should be done. Mainly there are two major strategies :

- Using existing requests :

  C->S: SignRequest  ( ReqId and other input parameters set, 
<ResponseMechanism> = 'Pending' )
  C<-S: SignResponse ( ResultMajor = 'Pending' , no output )

  C->S: SignRequest  ( ReqId set, no other input parameters )
  C<-S: SignResponse ( ResultMajor = 'Pending' )

  ...

  C->S: SignRequest  ( ReqId set, no other input parameters )
  C<-S: SignResponse ( ResultMajor != 'Pending', output included )

PRO :
The existing request are used for this scenario, no new Request and 
Response types are introduced for sign and verify.
Core protocol remains as it is.

CON:
Extensive relaxation of the schema required.



- Introducing specialized requests :

  C->S: SignRequest ( ReqId and other input parameters set, 
<ResponseMechanism> = 'Pending' )
  C<-S: PendingResponse

  C->S: PendingRequest
  C<-S: PendingResponse 

  ...

  C->S: PendingRequest
  C<-S: SignResponse ( ResultMajor != 'Pending', output included as 
expected )

PRO :
Clear protocol.
Expressive schema.

CON :
Introducing four new Request / Response structures. Iirc we once decided 
not to introduce new requests.
Definition of the protocol within the schema.
The server responds with two different structures ( SignResponse / 
PendingResponse  ) due to the same request.


Trevor and Nick prefer the second approach !

Any comment / opinion / ideas welcome ...


Greetings

Andreas