Working with a client, I discovered change in the way digital signatures work from previous versions. Actually the client did the discovery as it was seriously affecting their workflow. At first I thought perhaps the client was doing something “wrong” (a UE, user error) or it was a bug, or there was a new setting for digital signatures. Thorough testing revealed that their workflow worked (obviously) in Acrobat 7 and 8, but did not in Acrobat 9.1.

The official word from Adobe is that the change made in Acrobat 9.1 is the way digital signatures should work. In a document about the digital signature changes, “Adobe Acrobat 9 Digital Signatures, Changes and Improvements” it does note: “In certain workflows, these improvements may require you to revise business processes that use signed or certified PDF documents.” This PDF is available here:
http://www.adobe.com/devnet/reader/articles/readercomp_digitalsignatures.pdf 
Whereas it doesn’t specifically address my clients issue, read broadly, it does make seem to cover it.

Here’s the scenerio:
The client’s workflow (a manufacturing company) routes a PDF (containing PDF) with an attached PDF around a work group. Each member of the workgroup opens the PDF attachment, makes comments on it, then signs off on the containing PDF and passes it along to the next person. Prior to Acrobat 9.1 (Acrobat 7 & 8) this worked fine with multiple comments and multiple signatures. With Acrobat 9.1 after the first signature was made to the containing PDF, no further comments could be made on the attached PDF, although comments could be made to the containing PDF after one of more signatures. I searched high and low for a way around this, but there was no other option, the attachment was “locked down.” Nor could it be saved outside the containing PDF, commented upon by multiple people and re-added to the containing PDF. Reaching out to Adobe, I was directed to the “Adobe Acrobat 9 Digital Signatures, Changes and Improvements.”

Workaround:
As a way around this I recommeneded the 2 PDFs be put in a PDF Portfolio (a new feature with Acrobat 9) That way one PDF could be commented upon by multiple people and signed-off on the other PDF. Another option would be to combine both PDFs into a single PDF as multiple comments and multiple signatures are allowed on the same PDF. The client decided to revert back to Acrobat 7 to maintain their current workflow. As on Windows (as opposed to Mac), only one version of Acrobat can be installed, it would mean Acrobat 9 would have to be uninstalled. I felt this was unfortunate as there are many other improvements to Acrobat 9, including, but by not means limited to, a big improvement in speed.

Here’s a screen shot of the issue after a signature:



Here’s a screenshot of my proposed workaround:



It makes sense that a digital signature should lock down a PDF, by definition. However, it also makes sense, at least to me, that there should be an option to comment on an attachment, if desired, since you can multi-comment after a signature has been applied to the containing PDF.