Mailing List Archive

Multiple UIDs or multiple master keys?
1: When revoking a UID from my key, it asks for a reason. What happened to reasons 1, 2, and 3?

Please select the reason for the revocation:
0 = No reason specified
4 = User ID is no longer valid
Q = Cancel

2: What benefits benefits are there to having separate master keys for personal and professional use? Outside of not wanting the identities linked, because I am not yet famous enough for that.

_______________________________________________
Gnupg-users mailing list
Gnupg-users@gnupg.org
http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Multiple UIDs or multiple master keys? [ In reply to ]
> 1: When revoking a UID from my key, it asks for a reason. What
> happened to reasons 1, 2, and 3?
Let's hop in the Wayback Machine and look at the old specification for
OpenPGP, called RFC2440.

=====

5.2.3.22. Reason for Revocation

(1 octet of revocation code, N octets of reason string)

This subpacket is used only in key revocation and certification
revocation signatures. It describes the reason why the key or
certificate was revoked.

The first octet contains a machine-readable code that denotes the
reason for the revocation:

0x00 - No reason specified (key revocations or cert revocations)
0x01 - Key is superceded (key revocations)
0x02 - Key material has been compromised (key revocations)
0x03 - Key is no longer used (key revocations)
0x20 - User id information is no longer valid (cert revocations)

Following the revocation code is a string of octets which gives
information about the reason for revocation in human-readable form
(UTF-8). The string may be null, that is, of zero length. The length
of the subpacket is the length of the reason string plus one.

=====

Reasons 1, 2, and 3 are simply not used by UID revocations.

To answer your next question of "why is 'User ID information is no
longer valid' number 4, instead of 32 (hexadecimal 20) like it is in the
spec?", I'm guessing to prevent people from wondering what happened to
the other 30-odd (nonexistent) options. :)

_______________________________________________
Gnupg-users mailing list
Gnupg-users@gnupg.org
http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Multiple UIDs or multiple master keys? [ In reply to ]
On Dienstag, 14. Juli 2020 02:48:06 CEST Philihp Busby via Gnupg-users wrote:
> 2: What benefits benefits are there to having separate master keys for
> personal and professional use? Outside of not wanting the identities
> linked, because I am not yet famous enough for that.

You might not want to store your personal master key on a computer provided
(and controlled) by your employer.

Also: Ask yourself what happens when you change the employer. Your employer
might want you to revoke the key. And your new employer probably doesn't want
the old employer's UID on the key you use for the new employer.

If you are self-employed and/or use a smartcard for you master key, then those
reasons may not be that relevant.

But I suggest to ask the opposite question: What benefits are there for _not_
having separate master keys for personal and professional use?

Regards,
Ingo
Re: Multiple UIDs or multiple master keys? [ In reply to ]
On 2020-07-14 at 00:48 +0000, Philihp Busby via Gnupg-users wrote:
> 2: What benefits benefits are there to having separate master keys for
> personal and professional use? Outside of not wanting the
> identities linked, because I am not yet famous enough for that.

When the day comes that I get sucked into a legal discovery motion
through my employer and they start demanding private keys, I don't want
to have to rely upon the patience of my side's counsel to explain that
--show-session-key/--override-session-key will do just fine.

I want to be able to roll work keys, re-encrypt what needs to be
re-encrypted, and after I lose the argument about --show-session-key,
minimize the damage.

Don't cross the streams. Don't use private email for work purposes.
Avoid handling sensitive personal stuff on work email addresses. Don't
use keys which are "yours" in a context where someone with the power to
get you fired can start arguments because you're not cooperating. Don't
use a key "owned" by a legal entity to secure personal communications or
secrets.

It's not really hard to have two keys and keep them separate. And of
course if you're only using a computer which is the property of your
employer, you've read the corporate handbook and other documents
explaining what they own and don't own before letting such a device have
access to your personal keys.

None of this is about the cryptography of one key or two keys. All of
this is around the social and legal constructs within which any keys get
used.

-Phil

_______________________________________________
Gnupg-users mailing list
Gnupg-users@gnupg.org
http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Multiple UIDs or multiple master keys? [ In reply to ]
On 2020-07-14T11:20:53+0200 Ingo Kl?cker <kloecker@kde.org> wrote 2.5K bytes:

> On Dienstag, 14. Juli 2020 02:48:06 CEST Philihp Busby via Gnupg-users wrote:
> > 2: What benefits benefits are there to having separate master keys for
> > personal and professional use? Outside of not wanting the identities
> > linked, because I am not yet famous enough for that.
>
> You might not want to store your personal master key on a computer provided
> (and controlled) by your employer.

Is this alleviated by subkeys? i.e. it is not necessary to keep the master key on another's device.

> Also: Ask yourself what happens when you change the employer. Your employer
> might want you to revoke the key. And your new employer probably doesn't want
> the old employer's UID on the key you use for the new employer.

That's what I've done; revoke it. I have not had any employers ever care about my weird PGP thing, but they disable my access to the email when I got fired, of course.

> If you are self-employed and/or use a smartcard for you master key, then those
> reasons may not be that relevant.
>
> But I suggest to ask the opposite question: What benefits are there for _not_
> having separate master keys for personal and professional use?

The things I found are limits/benefits:
- I can only have one 'default' key in my gpg.conf
- My global gitconfig can only have one user.signingKey

_______________________________________________
Gnupg-users mailing list
Gnupg-users@gnupg.org
http://lists.gnupg.org/mailman/listinfo/gnupg-users
Re: Multiple UIDs or multiple master keys? [ In reply to ]
On Mittwoch, 15. Juli 2020 05:03:17 CEST Philihp Busby via Gnupg-users wrote:
> On 2020-07-14T11:20:53+0200 Ingo Kl?cker <kloecker@kde.org> wrote 2.5K
> bytes:
> > On Dienstag, 14. Juli 2020 02:48:06 CEST Philihp Busby via Gnupg-users
> > wrote:
> > > 2: What benefits benefits are there to having separate master keys for
> > > personal and professional use? Outside of not wanting the identities
> > > linked, because I am not yet famous enough for that.
> >
> > You might not want to store your personal master key on a computer
> > provided
> > (and controlled) by your employer.
>
> Is this alleviated by subkeys? i.e. it is not necessary to keep the master
> key on another's device.

Yes and no. Yes, because your master key cannot be compromised if it's kept
off of the computer controlled by your employer.

But it will create problems for people who want to send you encrypted messages
because there's no way for them to know which of the encryption subkeys to
use. You may work around this by making sure that the non-personal encryption
subkey is newer than then personal one because, AFAIK, gpg will automatically
select the newest encryption subkey. But that's a fragile setup.


> > But I suggest to ask the opposite question: What benefits are there for
> > _not_ having separate master keys for personal and professional use?
>
> The things I found are limits/benefits:
> - I can only have one 'default' key in my gpg.conf
> - My global gitconfig can only have one user.signingKey

Those benefits make sense if you use your personal user account on your
personal computer also for professional stuff. Otherwise, I see no benefit in
having identical configurations on different computers. My work-work computers
have always been configured completely differently from my personal computers.

In my opinion using separate master keys outweighs those minor conveniences of
using the same master key by far. I have always used separate master keys in
the past. And, in fact, I find it more convenient because it saves me the
hassle of juggling around with different subkeys. Your mileage may vary.

Regards,
Ingo
Re: Multiple UIDs or multiple master keys? [ In reply to ]
On Wed, 15 Jul 2020 11:03, Ingo Klöcker said:

> But it will create problems for people who want to send you encrypted messages
> because there's no way for them to know which of the encryption subkeys to
> use. You may work around this by making sure that the non-personal encryption

BTW, I was once considering to add notations to the subkeys and then let
gpg select a subkey based on the "--sender me@mydomain" option. This
would solve the problem. It will make things even more complex so it is
unlikely that this will be implemented.

So indeed, I would also suggest to use different keys for different
rules.


Shalom-Salam,

Werner

--
Die Gedanken sind frei. Ausnahmen regelt ein Bundesgesetz.