[Mailman-Developers] GSoC Updates

[Stephen J. Turnbull]

Abhilash Raj writes:

 > After midterm evaluations I have been working on signing the message
 > using one the keys associated with the list, now since `python-gnupg`
 > does not allow selecting keys with key credentials( like address or
 > list-name name)

Have you tried this?  In the GPG documentation, "key ID" often
actually means any of the above.[1]  If python-gnupg simply passes its
argument to the gpg process, it should Just Work.  Anyway, it seems to
work for me (some output edited for clarity):

venv27 abhilash 15:39$ python2.7
Python 2.7.5 (default, Aug  1 2013, 23:58:20) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
No entry for terminal type "emacs";
using dumb terminal settings.
>>> from gnupg import GPG
>>> gpg = GPG(gnupghome='/Users/steve/.gnupg',keyring='test-pub',secret_keyring='test-sec')
>>> gpg.list_keys()
[{'dummy': u'', 'keyid': u'17A810C33BDFEFA8', 'expires': u'',
  'subkeys': [[u'2C376F1897FD6C1C', u'e']], 'length': u'2048',
  'ownertrust': u'u', 'algo': u'1',
  'fingerprint': u'A36D6B345C18B02E695B8B7917A810C33BDFEFA8',
  'date': u'1376462161', 'trust': u'-', 'type': u'pub',
  'uids': [u'GPG Test User <gpg-tester at turnbull.sk.tsukuba.ac.jp>']},
 {'dummy': u'', 'keyid': u'87EBCC0B6DF8B373', 'expires': u'',
  'subkeys': [[u'18E03AE36F3B6DAD', u'e']], 'length': u'1024',
  'ownertrust': u'-', 'algo': u'17',
  'fingerprint': u'A9FC56DBD48F5E5B61B7137487EBCC0B6DF8B373',
  'date': u'1183228371', 'trust': u'-', 'type': u'pub',
  'uids': [u'Stephen J. Turnbull (XEmacs Reviewer) <stephen at xemacs.org>']}]
>>> crypted = gpg.encrypt(u'A bit of random text.', u'stephen at xemacs.org', always_trust=True)
>>> str(crypted)
'-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.4.14
(Darwin)
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=olXg
-----END PGP MESSAGE-----
'
>>> of = open ('/tmp/cryptfile', 'w')
>>> of.write(str(crypted))
>>> of.close()
>>> signed = gpg.sign('A bit of random text.', passphrase=u'Not useful without my keyring.', keyid=u'gpg-tester at turnbull.sk.tsukuba.ac.jp')
>>> str(signed)
'-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

A bit of random text.
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14
(Darwin)

iQEcBAEBAgAGBQJSCz30AAoJEBeoEMM73++oWGcH/jS3AJ6OZLm8JHiLAI0AzCXe
muRVhPPfGrqL/Jr+l9WA8Zj3pClHa04H0ha3nvYFHPhN30lFDDw56iCPMA+DbJbr
2BeqUSfJj36EGHOi8yV5iljZA4NhAw9qqhwQz7kas+KTeY8+98DQDS10ixVZ92Gv
NDxQCKcyTj+6leqy3ePRAgXP5DouTGXntupzPQzcbQW6L8X6h6STOiLAAGKXpGJm
t4Fruvbb3kAcqDGCp5Y9kLrxd1unlCp9leoeJeG5NZ5IcI2B4qUwqKdydu9ZMJxS
kJYJR1ZNVMtQh/kMNA87GMNv4nd8d5QPD+bm5b4L5BDlibzMGb5Q80mJAKD5xqo=
=qHjE
-----END
PGP SIGNATURE-----
'
>>> 

Decryption of the encrypted file works.  I didn't verify the
signature, but it looks like it's working.

 > Also I understand that keeping key safe is one of the important
 > tasks but for the time-being I am simply adding the public and
 > secret keyrings in "VAR_DIR/gpg/", all the list's private keys are
 > in `secring.gpg` and all the list's public keys are in
 > `pubring.gpg` and all the user's public keys are in
 > `userring.gpg`. It will be changed to keep the secret keys at a
 > more safer location.

I agree with Richard that there's no particular reason to do anything
but put the public keys on one ring.

I don't see any point in putting the private keys somewhere else.  As I
wrote elsewhere, the weak point in the private keys is the need to
supply a password, not the location of the file containing the key.  I
wonder if there may not be a way to do this using agent forwarding so
that the private keys are kept on a different host.

The only issue I can see is that *if* at some point it becomes
feasible to use agent forwarding, I suspect only one agent can be used
per GPG subprocess.


Footnotes: 
[1]  Has anybody else noticed that both gpg's UI and its documentation
seem designed to make it as hard to use as possible?