Cheap/free way to create trusted PDF signatures?
 

Does anyone know of a certificate authority that issues certificates suitable for signing PDFs that Acrobat will trust out of the box? Everything I find seems to be several hundred dollars.

I think I found an answer: the South African Post Office issues certificates if you can demonstrate you can access a given email address. They cost about $5 for a year.

I tried one out (they have a handy "Try" feature that issues a free cert for 30 days) and Acrobat on a colleague's compute liked it. But they only use 1024 bit RSA keys, which is not considered secure these days. So it's not a great answer, but it's not awful either.

I'd be a bit concerned about that particular requirement considering how common hacking into people's email accounts is. At the very least I'd insist on 2FA for whatever email address gets that certificate (though that's probably something everyone should be doing regardless of whether a certificate is required).

Sure, but the alternative here is just me scribbling out the old John Hancock, which hardly seems like a paragon of security either. Ink on paper? How 18th century.