Re: [gentoo-project] [RFC] OpenPGP Authority Keys to provide validity of developer/service keys

[Rich Freeman]

On Sat, Feb 23, 2019 at 12:08 PM Michał Górny <mgorny@g.o> wrote:
>
> The question is: how can you actually guarantee that users that don't
> understand OpenPGP/GnuPG basics can actually comprehend the basic
> necessities of keeping their key secure?

I think you need to distinguish between people who don't understand
gpg and people who simply don't agree with you.  As you pointed out,
in its default config gpg generates an encryption subkey.  Though, I
don't think the default config is actually Gentoo-compatible.

> Next thing I learn is that
> people are not protecting their keys with password because
> the instructions didn't say they had to.  And GnuPG *only warned*.

While it is always a good idea to protect a key with a password, this
really only protects the key while it is at rest.  Chances are if an
attacker can read the keyring from disk, they can probably also
intercept the passphrase, either from the keyboard or from the gpg or
agent process.

If we really want to protect keys then it probably makes sense to
generate them on hardware keys, and use a hardware key which makes it
possible to distinguish keys that were generated on-hardware and are
non-exportable from keys that were generated in software (probably by
use of a remote attestation signing key in the hardware).  I'm not
sure if such hardware keys exist.  I guess another option is to have a
trusted person generate the keys on-hardware, load the key ID into
LDAP, and not let devs change their LDAP settings.  Of course that
would give the person generating keys the ability to secretly generate
some, keep a copy of the private key, and then load it on the
hardware.  Then again, with any hardware device you're also trusting
the manufacturer to not have a backdoor either.

Bottom line is that PKI is hard.  You can encourage devs to follow
better practices, just as you can encourage them to run repoman, but
in the end they're going to have to be convinced that they really are
the weakest link, otherwise they'll probably quietly ignore you.

-- 
Rich