Post by AnonymousI've seen on some Web sites that people are offering some sort of
utilities for sale that are supposed to allow you to clearsign .PDF
files.
You can clearsign any file with PGP or GPG. You don't need anything extra.
Post by AnonymousDoes that just generate a seperate signature file?
No, a separate signature file is called a "detached signature" Clearsigning
is wrapping the signature around the text itself. It is really only
practical for text files where it doesn't interfere with a human reading it.
Post by AnonymousAnd is there any free software that will actually put the clearsigned
pgp/gpg in the document?
No, there isn't any software at all that can do that, that will break
Acrobat reader. However the software Adobe sells that creates Acrobat
documents can sign PDFs it creates using your X.509 signing key.
If you don't have an X.509 cert you'll have to make your own with openssl,
pay for one, or get a free one. You don't actually need the certificate to
sign but along with your cert you also get signing and encrypting key pairs.
Post by AnonymousOf course then you'd have a hard time getting pgp/gpg to reazd it wouldn't
you?
No, if you clearsign a PDF you will break Acrobat reader. PGP or GPG could
read and verify it just fine. The problem is you can't change the format of
a PDF. That's why people sell tools to embed signatures in PDF files. Those
tools can be worth buying. The only other option is to pay for Acrobat.
If a detached signature will work for you then you don't have to buy
anything if you already have PGP. Or get GPG.
Post by AnonymousAnyway, signing a .pdf document sounds like something I may need to do so
any advice would be appreciated.
Wherever you go, there you are!