Mailing List Archive

On Tue, 2021-11-16 at 18:20 +0200, Teemu Likonen wrote:
> Am I seeing a starting trend here? Do some people think that it is
> better practice to have only have email address as user id? What
> might be their reason? Or maybe it's not a trend and doesn't mean
> anything. I got curious anyway. Add your speculation. :-)

When selecting a key for either encryption or verification purposes,
only the email address part is meaningful. "John Smith
<jsmith@example.com>" and "John David Smith (work email)
<jsmith@example.com>" are functionally equivalent. The "Real Name" and
"Comment" portions of the userID are mere conventions and, if you have
an address book, entirely redundant.

It is reasonable therefore to take the view that the non-email portion
of a userID is cruft at best (and an unnecessary leakage of personal
information at worst).

A

* 2021-11-16 17:06:02+0000, Andrew Gallagher via Gnupg-users wrote:

> The "Real Name" and "Comment" portions of the userID are mere
> conventions and, if you have an address book, entirely redundant.

Thanks. That is rather technical point of view and correct in that
sense. In my opinion it is a bit too nerdy because real names are
convenient for other people. For example, I have to address books:

1. Actual address books for people, their home addresses, phone numbers
and emails. None of these people have OpenPGP key.

2. Second "address book" is my OpenPGP keyring. It groups persons'
names, their email and other key data. If many keys don't have name
in their user id it could be inconvenience. Computer programs can
find keys but often we need also manual "gpg -k" etc. Real names
help there.

(I understand that some people need to protect their identity and
use some random strings in user id's. That is completely different
from usual public communication.)

But this is nothing important. Key's owner decides.

--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: 6965F03973F0D4CA22B9410F0F2CAE0E07608462

Am Dienstag 16 November 2021 18:06:02 schrieb Andrew Gallagher via
Gnupg-users:
> On Tue, 2021-11-16 at 18:20 +0200, Teemu Likonen wrote:
> > Am I seeing a starting trend here? Do some people think that it is
> > better practice to have only have email address as user id?

Some email providers offering pubkeys via WKD only accept email-only
uids, see the policy flag "mailbox-only" in
https://datatracker.ietf.org/doc/draft-koch-openpgp-webkey-service/13/

> It is reasonable therefore to take the view that the non-email portion
> of a userID is cruft at best (and an unnecessary leakage of personal
> information at worst).

There are two potential problems here:
a) usability in case of deliberately missleading information
madam president <joe.doe@example.ntvtn.de>
b) abuse prevention and responsibility on case of illegal information
Mr X is an XXX he lives at Drowning Street YY <joe.doe@example.ntvtn.de>

However an email provider can exclude those ab-use-cases in their terms of
service with their users and hold them responsible in case of violation.

So it is still okay to use uids which are no email addresses or some uids with
more or other information. Just do not expect other services to carry this
information, do not fully trust them (just like you do not trust pubkeys by
default) and be prepared to take responsibility for the contents you are
transmitting.

Best Regards,
Bernhard

--
www.intevation.de/~bernhard   +49 541 33 508 3-3
Intevation GmbH, Osnabrück, DE; Amtsgericht Osnabrück, HRB 18998
Geschäftsführer Frank Koormann, Bernhard Reiter, Dr. Jan-Oliver Wagner

On 17/11/2021 14:40, Teemu Likonen wrote:
> 2. Second "address book" is my OpenPGP keyring. It groups persons'
> names, their email and other key data. If many keys don't have name
> in their user id it could be inconvenience. Computer programs can
> find keys but often we need also manual "gpg -k" etc. Real names
> help there.

It may sound like a nerdy quibble, but it's a fundamental weakness.
Mapping a "Real Name" to an email address is a conceptually different
thing from mapping an email address to a public key. Conflating the two
introduces confusion about what exactly is being verified by the
cryptographic toolchain. If an MUA's address book is not sufficiently
user-friendly, then that's a user interface shortcoming that can't be
fixed by introducing RFC-822 "Real Names", which were highly
questionable long before email encryption was invented...

--
Andrew Gallagher

> Mapping a "Real Name" to an email address is a conceptually different
> thing from mapping an email address to a public key.

Except that should we be mapping keys to email addresses in the first
place?

When we sign a certificate we make an assertion that this cryptographic
material is controlled by this entity. I control the cryptographic
material associated with certificate 0x1DCBDC01B44427C7.
rjh@sixdemonbag.org controls nothing -- it's just one of several places
I pick up mail.

I have long considered mapping keys to email addresses to be a
fundamental flaw. It obscures exactly what it is we're trying to
assert: that cryptographic material is controlled by *people*.

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On 17/11/2021 18:15, Robert J. Hansen wrote:
>> Mapping a "Real Name" to an email address is a conceptually different
>> thing from mapping an email address to a public key.
>
> Except that should we be mapping keys to email addresses in the first
> place?
>
> When we sign a certificate we make an assertion that this cryptographic
> material is controlled by this entity.  I control the cryptographic
> material associated with certificate 0x1DCBDC01B44427C7.
> rjh@sixdemonbag.org controls nothing -- it's just one of several places
> I pick up mail.

A cryptographic signature does not attest that anything belongs to you,
the meatspace person - it merely attests a relationship between some
cryptographic material and a particular identifier. The interpretation
of the identifier is context-dependent and highly subjective.

If I want to send an email to you, I have to identify you to my MUA. If
I want to encrypt it, I have to ask the MUA to associate the identifier
I just gave it with a key. I either select your name from an address
book (in which case the unique ID is your email address) or I type in
your email address by hand. It doesn't matter how many other identifiers
(emails, post boxes, passport numbers) you have - from my POV, and that
of my MUA, they are irrelevant because they don't let me identify you
any more precisely than I already can with just one.

The cryptographic binding is always between key material and a
machine-readable identifier. This identifier may or may not be globally
unique, but it should be unique in the context of the system within
which it is used (e.g. my MUA). The mapping of contextual identifiers
onto meatspace is a philosophical question that is beyond the reasoning
capability of a computer, and the ability of natural persons to assume
and discard identifiers is a feature, not a bug.

> I have long considered mapping keys to email addresses to be a
> fundamental flaw.  It obscures exactly what it is we're trying to
> assert: that cryptographic material is controlled by *people*.
Some cryptographic material is created, used and destroyed without any
human interaction whatsoever, e.g. TLS session keys. The session key is
signed by the server key to state "this session key is controlled by me"
(i.e. the server). The server may be controlled by an organisation, and
the organisation by people (or the people by the organisation, depending
on your point of view!).

The point being that there are many layers of abstraction between the
cryptographic material and a natural person. Software can only make and
test claims about some of those layers at best, and some of those layers
may not even be meaningful to the end user, depending on the context.

--
Andrew Gallagher

On Wed, Nov 17, 2021 at 04:40:46PM +0200, Teemu Likonen <tlikonen@iki.fi> wrote:

> * 2021-11-16 17:06:02+0000, Andrew Gallagher via Gnupg-users wrote:
>
> > The "Real Name" and "Comment" portions of the userID are mere
> > conventions and, if you have an address book, entirely redundant.
>
> Thanks. That is rather technical point of view and correct in that
> sense. In my opinion it is a bit too nerdy because real names are
> convenient for other people.

Real names aren't that useful. They're hardly unique,
even/especially within a single family.

In Australia, voting is mandatory (yay! for now).
Someone I know once received a letter from the
gorvernment asking why they didn't vote, and at the
same time, their father, who had with the same name and
address, received a letter asking why they voted twice
(or maybe it was the other way around). :-)

cheers,
raf


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* 2021-11-18 13:22:52+1100, raf via Gnupg-users wrote:

> Real names aren't that useful. They're hardly unique,
> even/especially within a single family.

That continues the technical or nerdy point of view. "Real names are not
unique. Therefore they are not (that) useful." Sometimes crypto nerds
seem to say that if everything is not perfect then all is lost. In
practice, real names are very useful for humans.

But another thing is that two separate things probably shouldn't be in
the same technical information field. Currently we could do this:

pub ed25519 2021-11-07 [C] [expires: 2023-11-07]
[Not really my key, so fingerprint removed.]
uid [...] Teemu Likonen
uid [...] <tlikonen@iki.fi>
uid [...] <teemu.likonen@iki.fi>
uid [...] <dtw@kapsi.fi>

Then other people could more carefully certify different information in
user id's.

--
/// Teemu Likonen - .-.. https://www.iki.fi/tlikonen/
// OpenPGP: 6965F03973F0D4CA22B9410F0F2CAE0E07608462