WG: AW: Fw: [dss-x] Visual Signatures profile

[Andreas Kuehne <kuehne@trustable.de>]

Hi Leonard !

Konrad said something very important yesterday :

'Think of requirements, not of existing solutions !'

I hope I remember it correctly ... but it's true anyway. 2D barcodes are 
funny stuff to impress my kids and colleagues, but our real use case is 
: Mass signing of PDF invoice documents. That's not a tricky requirement 
at all, but I just can't do it using DSS right now !

So I would like to go for a signing profile for PDF documents starting 
with the core's successful keep-it-simple approach in mind :

- One signature at a time
- Pre-configured signature field included in the document
- DSS's signature placement enhanced to be a pointer into a PDF doc
- No update of the PDF beyond the signature field

Same for Verification. I have no experience with timestamps in PDFs, 
maybe the simple signature approach will fit ??

This would introduce a new profile with focus on PDF as a signature 
container format, independent from the visual signature efforts. Does 
this makes sense to you ?

More sophisticated profiles may aggregate this functionality, but that's 
not my use case.


Opinions welcome

Andreas


----- Original Message ----
From: Leonard Rosenthol <lrosenth@adobe.com>
To: Andreas Kuehne <kuehne@trustable.de>; dss-x@lists.oasis-open.org
Sent: Monday, March 31, 2008 9:09:26 PM
Subject: RE: Fw: [dss-x] Visual Signatures profile

2D barcodes can be made to work for textual data (like a train ticket), 
provided that the canonicalization algorithm is standardized along with 
it.  W/o that algorithm, you have no clue how deal with white space (for 
example) when "rekeying" the data.  However, they don't suffice for rich 
content - even just rich text (fonts  & styles), let alone things like 
tables, raster & vector images, etc.  FWIW: We've been supporting 2D 
barcodes in PDF since version 1.5 (Acrobat 6) for our form fields.

The "please sign here" scenario, however, is somewhat simplistic for 
many real world documents - as many have multiple signers (husband/wife, 
employee/manager, etc).

While I don't disagree with your comment about DSS vs. PDF - you, 
yourself, are starting to cross the line when you start thinking about 
"required fields" and "seed values" (predetermined requirements for 
signing).

Leonard




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