example: key creation

* Script to generate a new key with encryption subkey taking input
  from interactive prompts.
* Will also take a passphrase via pinentry and uses passphrase caching
  of five minutes when used in conjunction with the temp homedir
  script.

lang/python/examples/howto/create-key.py

@@ -0,0 +1,95 @@
+#!/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 os.path
+
+print("""
+This script generates a new key which does not expire.
+
+The gpg-agent and pinentry are invoked to set the passphrase.
+""")
+
+c = gpg.Context()
+
+homedir = input("Enter the GPG configuration directory path (optional): ")
+uid_name = input("Enter the name of the user ID: ")
+uid_email = input("Enter the email address of the user ID: ")
+uid_cmnt = input("Enter a comment to include (optional): ")
+key_algo = input("Enter the key algorithm, RSA or DSA (default is RSA): ")
+key_size = input("Enter the key size (2048-4096, default is 2048): ")
+
+if homedir.startswith("~"):
+    if os.path.exists(os.path.expanduser(homedir)) is True:
+        c.home_dir = os.path.expanduser(homedir)
+    else:
+        pass
+elif os.path.exists(homedir) is True:
+    c.home_dir = homedir
+else:
+    pass
+
+if len(uid_cmnt) > 0:
+    userid = "{0} ({1}) <{2}>".format(uid_name, uid_cmnt, uid_email)
+else:
+    userid = "{0} <{2}>".format(uid_name, uid_email)
+
+if key_algo.lower() == "dsa":
+    ka = "dsa"
+else:
+    ka = "rsa"
+
+if len(key_size) == 4:
+    try:
+        ks0 = int(key_size)
+    except ValueError:
+        ks0 = None
+    if ks0 is None:
+        ks = "2048"
+    else:
+        if ks0 < 2048:
+            ks = "2048"
+        elif ka == "dsa" and ks0 > 3072:
+            ks = "3072"
+        elif ka == "rsa" and ks0 > 4096:
+            ks = "4096"
+        else:
+            ks = key_size
+else:
+    ks = "2048"
+
+keyalgo = "{0}{1}".format(ka, ks)
+
+newkey = c.create_key(userid, algorithm=keyalgo, expires=False,
+                      passphrase=True, certify=True)
+key = c.get_key(newkey.fpr, secret=True)
+
+if ka == "rsa":
+    newsub = c.create_subkey(key, algorithm=keyalgo, expires=False,
+                             passphrase=True, encrypt=True)
+else:
+    newsub = c.create_subkey(key, expires=False, passphrase=True,
+                             encrypt=True)