I am needing long-term retention (50-years or more) of my digital documents and for legal purposes, I also need to apply a validation to the document indicating that I certify this as an official digital document of the agency I work for. I am able to apply Certificate-based Signature to PDFs that I created from the Microsoft Certificate Store. However, when I try to save to PDF/A, I am unable to meet the standard, and I get the error message - Signature Reference Dictionary has Digest Location entry and Permissions Dictionary had DOCMDP entry. I don't understand the technical language.
I am wondering if a Certificate-based Signature is simply incompatible with a PDF/A. I have searched the Adobe help references but have not been able to resolve the issue. Can anyone suggest what I might do differently.