Re: Default encryption for Message

[Jens Lechtenboerger <jens.lechtenboerger@fsfe.org>]

On 2014-09-25, Daiki Ueno wrote:

> Jens Lechtenboerger <jens.lechtenboerger@fsfe.org> writes:
>
>> I fail to see why encrypt-to-self should be tied to sign-related
>> variables.
>
> The variable name might not be too intuitive, but maybe you could
> imagine how GPG signing and encryption work.  Decryption keys are
> usually same as signing keys.

I’m not sure about that, but this may be a side issue.  GnuPG
creates an encryption subkey by default.

> Suppose that one has three keys associated with his e-mail address.  Key
> A is for encrypted e-mail communication with his colleagues, key B is
> for communicating with friends, and key C is for automatic signing of
> tarballs.
>
> Here, those keys are more securely protected in order of A, B, and C.
> He doesn't want to use key C for any e-mail encryption.  He doesn't want
> to use key B for confidential communication within his company.
>
> This might sound hypothetical but I do have a similar setting.  How do
> you address this situation with ~/.gnupg/gpg.conf options and Bcc?

Apparently, we have been talking about different things.

I was interested in mml2015-encrypt-to-self and looked at its doc
string.  Setting to t fails.  You explained that
mml2015-sign-with-sender or mml2015-signers are necessary.
However, I don’t want to sign and suggested gpg.conf/Bcc instead.

In your scenario, I see two choices, say concerning Alice with those
three keys.

(1) Friend Bob wants to send a message to Alice and is supposed to
choose the correct key B (but neither A nor C).

(2) Alice wants to send an encrypted message to colleague Charlie,
and she wants to make sure that the message is encrypted to her key
A (but neither B nor C) in addition to Charlie’s key.

For (1), my code sets mm-encrypt-option to 'guided to enforce a
manual choice so that Bob learns about the existence of those three
public keys in the first place.  (Ted Zlatanov suggested to save
that choice.)

For (2), I think that another variable would be necessary to
customize what key to use for what recipient.  (Gnus could ask if it
detects multiple encryption keys.)

I don’t see how either case is supported by mml2015, though.  What
is your configuration?

Besides, what is the intended meaning for signatures if
mml2015-signers contains multiple keys?

Best wishes
Jens