Python script to sign the contents and verify PGP-signed content on your Windows/Mac/Linux clipboard

gpgboard.py

import argparse
import os
import sys

import gnupg
import pyperclip

parser = argparse.ArgumentParser(
    description="GPG clearsign whatever is on your clipboard and copy the signed data back"
)
parser.add_argument(
    "--verbose",
    action="store_true",
    help="be verbose, show additional output -- on STDERR -- to not interfere with function",
)
parser.add_argument(
    "--gpg",
    action="store",
    type=str,
    help='Location of GPG (1.4.x and 2.x supported), defaults to "/usr/local/opt/gpg2/bin/gpg"',
)
parser.add_argument(
    "--key",
    action="store",
    type=str,
    help="Key id to use, defaults to first in your secret keyring",
)
parser.add_argument(
    "--passphrase", action="store", type=str, help="Passphrase for signing"
)
parsed = parser.parse_args()

if not parsed.gpg:
    parsed.gpg = "/usr/local/opt/gpg2/bin/gpg"

if not parsed.key:
    parsed.key = None

message = pyperclip.paste()
os.environ["GPG_TTY"] = os.ttyname(sys.stdout.fileno())
if not message:
    print("Must have text on the clipboard to use", file=sys.stderr)
    sys.exit()
gpg = gnupg.GPG(gpgbinary=parsed.gpg, use_agent=True, verbose=parsed.verbose)
gpg.encoding = "utf-8"
if message.startswith("-----BEGIN PGP SIGNED MESSAGE-----"):
    verification = gpg.verify(message)
    if verification:
        print("verified")
    else:
        print("Does not verify")
else:
    signed_data = gpg.sign(
        message, clearsign=True, keyid=parsed.key, passphrase=parsed.passphrase
    )
    if parsed.verbose:
        print(signed_data, file=sys.stderr)
    pyperclip.copy(str(signed_data))

Added verification of signed messages

Made verbose default to False.