Hi everyone,
I'm fairly new to using PGP and Digital Signatures and I wanted to ask if it was possible to sign real world physical objects with a unique digital signature. I assume this is no doubt possible but I can't work out how to do it as from what I understand generally PGP uses a hash of a digital file combined with your private key in order to verify the source but also integrity of the file?
A use case would be if somebody didn't have access to the internet and had to use a postal service to send mail could they use a digital signature on the letter to verify the source of the file instead of a traditional hand written signature? I understand the shortcomings of doing such a thing, IE the digital signature can be intercepted and then copied to a different letter that wasn't written by the sender but I'd still be interested to find out how to do such a thing.
I use GPG Tools so for bonus kudos if somebody could point me in the direction of a tutorial that would show me how to do such a thing using GPG Tools that would be greatly appreciated.
