Emacs: Password-protect current pdf

from blog lmno.lol @alvaro, | ↗ original
UPDATE: Check out Password-protect current pdf (revisted) for a simpler version. Every so often, I need to password-protect a pdf. On macOS, Preview has a simple solution, but I figured there must be a command line utility to make this happen. There are options, but qdf did the job just fine. qpdf --verbose --encrypt USER-PASSWORD OWNER-PASSWORD...