example: decrypt file

* Decrypts a file taking file names as command line parameters.

lang/python/examples/howto/decrypt-file.py

@@ -0,0 +1,44 @@
+#!/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 Licensefor 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
+
+if len(sys.argv) == 3:
+    ciphertext = sys.argv[1]
+    newfile = sys.argv[2]
+elif len(sys.argv) == 2:
+    ciphertext = sys.argv[1]
+    newfile = input("Enter path and filename of file to save decrypted data to: ")
+else:
+    ciphertext = input("Enter path and filename of encrypted file: ")
+    newfile = input("Enter path and filename of file to save decrypted data to: ")
+
+with open(ciphertext, "rb") as cfile:
+    plaintext, result, verify_result = gpg.Context().decrypt(cfile)
+
+with open(newfile, "wb") as nfile:
+    nfile.write(plaintext)