Software Questions: Digital Signatures with Acrobat; Document Catalog Software

[Sasha Zucker]

I have two questions for the Austin STC. I would appreciate the benefit of
your collective knowledge and experience.

The first question concerns the use of digital signatures on PDF files using
Adobe Acrobat. At my organization, co-workers have tried using Acrobat to
digitally sign documents to indicate approval. However, they inform me that
they have been unsuccessful using Acrobat as a solution for the following
reason: If a second person signs a PDF document that has already been
signed, the existing signature immediately becomes invalid because the
document has been modified. Does anyone have any insight into this issue? It
should be possible for two people attach valid digital signatures to a PDF
at the same time, correct?

My second question concerns a software solution for the cataloging of
documents. My organization would like to assign ID numbers to documents as a
method of tracking them. These ID numbers could then be used in a catalog or
library. Can anyone suggest catalog software that could provide such a
solution?

Thank you for your assistance,

-- 
Sasha Zucker
Technical Writer
Nextrials, Inc.
sez at nextrials.com