gpgme/lang/python/examples/howto/clear-sign-file.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

from __future__ import absolute_import, division, unicode_literals

# Copyright (C) 2018 Ben McGinnes <ben@gnupg.org>
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU General Public License as published by the Free Software
# Foundation; either version 2 of the License, or (at your option) any later
# version.
#
# This program is free software; you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation; either version 2.1 of the License, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE.  See the GNU General Public License and the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU General Public License and the GNU
# Lesser General Public along with this program; if not, see
# <http://www.gnu.org/licenses/>.

import gpg
import sys

"""
Clear-signs a file with a specified key.  If entering both the key and the
filename on the command line, the key must be entered first.
"""

if len(sys.argv) > 3:
    logrus = sys.argv[1]
    filename = " ".join(sys.argv[2:])
elif len(sys.argv) == 3:
    logrus = sys.argv[1]
    filename = sys.argv[2]
elif len(sys.argv) == 2:
    logrus = sys.argv[1]
    filename = input("Enter the path and filename to sign: ")
else:
    logrus = input("Enter the fingerprint or key ID to sign with: ")
    filename = input("Enter the path and filename to sign: ")

with open(filename, "rb") as f:
    text = f.read()

key = list(gpg.Context().keylist(pattern=logrus))

with gpg.Context(armor=True, signers=key) as c:
    signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.CLEAR)
    with open("{0}.asc".format(filename), "wb") as f:
        f.write(signed_data)