On PAdES profile

[Juan Carlos Cruellas <cruellas@ac.upc.edu>]

Dear all,

I have been re-reading the current existing specifications for AdES 
signatures and for Visible signatures. Looking at the structure of the 
first one, it includes one abstract profile (AdES) and  two concrete 
profiles (CAdES and XAdES related). Looking at the specificities of 
PAdES, as Martin mentioned, PAdES generation and validation requests may 
also include contents related to the appearance of the signature or of 
the signature validation within the document.  My feeling is that the 
inclusion of this part within the document that profiles XAdES and CAdES 
signatures management, even if it is by  inheriting or incorporating the 
specifications  of visible signatures, would somehow break the 
homogeneity of the document. I mean, as it is now, the three parts of 
the document are similar in structure and parallel in contents, and this 
is so because through time, there have been efforts to keep XAdES and 
CAdES themselves aligned (although not completely successful in certain 
details). The incorporation of PAdES would somehow break this strong 
parallelism: for instance, PAdES does not manages references to 
validation material (i.e. their digest values) and as Martin points out 
the repertoire of forms is not similar to XAdES and CAdES one....not to 
mention all the potential optional inputs for requesting the generation 
of the visual appearance of the signature itself...

In the view of that, I would say that at this point in time I would be 
lightly inclined to generate a new document fully dedicated to PAdES 
generation and validation protocols, which, on one side would be a 
concrete instantiation of the AdES (further constraining some URIs etc.) 
and on the other would incorporate the visible signature profile....

What I would suggest is that each operation (SignRequest, 
ValidationRequest) is structured in two parts: the first one following 
as much as possible the concrete porfiles of XAdES and CAdES in its 
inner structure and a second part devoted to the visible aspects...

I do not have a very strong position on that, but as we had mentioned 
that during this time we should try to make our minds on this topic....

Regards

Juan Carlos.