Re: [dss] Schema TP5. ISSUE#1: Already applied transformations by the client

[Trevor Perrin <trevp@trevp.net>]

At 02:58 PM 10/6/2003 +0200, Juan Carlos Cruellas wrote:

>Somebody could say: "wait a moment!, it is not DOC-0 but DOC-1 the document
>that the client sends in the InputDocument!".
>Well, even in that case the processing would lead to bad ds:Signature 
>elements.

yeah, I think that would be the case.


>Suppose that the client sends DOC-1. In this case, according to the basic
>processing of our document:
>
>1. Computes the hash of DOC-1: HDOC-1.
>2. Generates the ds:Reference with the ds:Transforms that the client has
>applied to DOC-0 to get DOC-1.
>3. ENVELOPES DOC-1 WITHIN A ds:Object of the ds:Signature. AND HERE IT IS
>THE PROBLEM FOR THE VERIFICATION.
>
>In the verification:
>
>2.1 the dereferencing would get DOC-1. Then the transformations that
>the verifier would apply would lead him to a DOC-2 completely different!!
>and 2.2 would, of course fail!.


Hmm.  Right.  Could we avoid this by just saying that if you're sending a 
document for enveloping, you can't apply Transforms to it?

Trevor