example: python bindings encryption

* Since we don't want to encourage accessing the low level functions
  (e.g. op_encrypt), but since this example can still be useful to
  understand, renaming it and will add new encryption examples to
  match the instructions in the HOWTO.

1 files changed, 53 insertions, 0 deletions

diff --git a/lang/python/examples/low_level-encrypt_to_all.py b/lang/python/examples/low_level-encrypt_to_all.py
new file mode 100755
index 00000000..bad4220c
--- /dev/null
+++ b/lang/python/examples/low_level-encrypt_to_all.py
@@ -0,0 +1,53 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2016 g10 Code GmbH
+# Copyright (C) 2008 Igor Belyi <[email protected]>
+# Copyright (C) 2002 John Goerzen <[email protected]>
+#
+# 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 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 for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+"""
+This program will try to encrypt a simple message to each key on your
+keyring.  If your keyring has any invalid keys on it, those keys will
+be skipped and it will re-try the encryption."""
+
+from __future__ import absolute_import, print_function, unicode_literals
+del absolute_import, print_function, unicode_literals
+
+import sys
+import gpg
+
+with gpg.Context(armor=True) as c:
+    recipients = list()
+    for key in c.keylist():
+        valid = 0
+        if any(sk.can_encrypt for sk in key.subkeys):
+            recipients.append(key)
+            print("Adding recipient {0}.".format(key.uids[0].uid))
+
+    ciphertext = None
+    while not ciphertext:
+        print("Encrypting to %d recipients" % len(recipients))
+        try:
+            ciphertext, _, _ = c.encrypt(b'This is my message.',
+                                         recipients=recipients)
+        except gpg.errors.InvalidRecipients as e:
+            print("Encryption failed for these keys:\n{0!s}".format(e))
+
+            # filter out the bad keys
+            bad_keys = {bad.fpr for bad in e.recipients}
+            recipients = [r for r in recipients
+                          if not r.subkeys[0].fpr in bad_keys]
+
+    sys.stdout.buffer.write(ciphertext)