EU has an eIDAS law about qualified signatures and timestamps for years with even an original open-source implementation from EU. You can add it to the PDF and

EU has an eIDAS law about qualified signatures and timestamps for years with even an original open-source implementation from EU. You can add it to the PDF and keep it on your machine. It's verifiable by any court in the EU because it's "unbreakable". We use it for every document when communicating with officials and I think more people should do that. You don't need cool blockchains and stuff when you have cryptography.