Digital Signature TWG at PDF Week
The Digital Signature Technical Working Group chair lays out the work to be discussed at PDF Week Paris 2023.
About the author: I was a researcher at KU Leuven from 2016 to 2020, where I completed my PhD in mathematics. At the PDFa, I’m mostly active in the Forms, Digital Signatures and … Read more
The Digital Signatures Technical Working Group will be meeting in person at the upcoming PDF Week 2023 Paris (May 2nd, 16:00-17:30 CEST).
At our January meeting earlier this year, the group expressed interest in a variety of topics:
- Following an initiative by Foxit/Normex at the 2021 PDF Days, we are working on a draft to embed signing workflow information into PDF documents. The goal is to achieve better interoperability between different document signing platforms, and to make such workflows auditable using modern metadata standards. This document will likely be circulated as a tech note by the PDF Association.
- Another issue that has come up several times in the past relates to the difficulty of correctly processing incremental updates to a signed PDF document. This class of problems is hard to ignore when a document needs to be signed by multiple signers, and when designing tooling for standards like PAdES. The technical working group intends to contribute improvements in two ways:
- Fostering a better common understanding of PDF signature validation in general. One possible approach involves developing a set of sample documents for use in interoperability tests. Incremental update validation could be incorporated into that.
- Looking at alternative ways to embed signatures into PDF documents that rely less on incremental updates, and are more amenable to multi-user workflows. This opens the door towards various things that aren't currently possible, such as parallel signing. There are, however, many possible approaches, each with a different set of trade-offs. The plan is to explore some of those.
- Both tracks are essentially complementary in the sense that whatever alternative signature embedding scheme we end up proposing would not be a replacement for what we have today, so achieving a more fleshed-out consensus on what to do with "current-gen" PDF signatures is useful regardless.
We intend to engage with some of these topics over the course of our meeting in Paris. If you not able to join us in Paris, remote attendance will be possible.