PGP public key servers are useful! [noise?]

-----BEGIN PGP SIGNED MESSAGE-----

To: cypherpunks@toad.com
Date: Mon Aug 05 16:43:42 1996
Over the last couple of weeks, I've noticed a lot
of subscribers who PGP clearsign their messages,
but who haven't uploaded their keys to any of
the public keyservers.

Those keys are most useful when they're
available to people who might want to use them,
so I'm asking those of you who haven't sent
them to a keyserver to do so.

(The quick version: paste your key in cleartext
into a letter, sent to pgp-public-keys@pgp.mit.edu
with the subject: ADD.  If you don't have it
in cleartext, do pgp -kxa and follow the prompts.)

TIA,
dave





- ---- David E. Smith  POB 324  Cape Girardeau MO USA 63702
dsmith@prairienet.org   http://www.prairienet.org/~dsmith
send mail of 'send pgp-key' subject for my PGP public key
  "Heard a lot of talk about this Jesus, a man of love,
   a man of strength; but what a man was two thousand
    years ago means nothing at all to me today ... "
-----BEGIN PGP SIGNATURE-----
Version: 2.6.2
Comment: Automagically signed with Pronto Secure for Windows.

iQEVAwUBMgZrGzVTwUKWHSsJAQGRtwf/TPjleUXsqf2GcEsutZNnyYD82bYM2ZT/
NQm0BeUTcNdU+jA/2z5aiy+FRozcL6EeIDPULtCGeMvDYu95vBOjnimIxMjng9J6
mIpFIQzXUN4ZDdE7m1khbn8Vdk/V0kehQL318LzB484SQILWNYvTNrj/cDq6CdKW
RMyyOH3+5VH1xRZJjFYvTsKnCszmtZIIvrjOt9+nX/j02bWnZRV7IGbOFjSrCL6p
r1TZG/TnU60YGz/TaUhp5OCj0bFlkFQlg+NmcwR9j4rlIza9ujBSuGIcflMRWTG3
ighrCC9cpL1v/qJkHXKy67xdvIZWlq7UiyqTRUEBg7rwjSBca0YgZQ==
=rDtm
-----END PGP SIGNATURE-----

"David E. Smith" <dsmith@prairienet.org> writes:
> Over the last couple of weeks, I've noticed a lot
> of subscribers who PGP clearsign their messages,
> but who haven't uploaded their keys to any of
> the public keyservers.
> 
> Those keys are most useful when they're
> available to people who might want to use them,
> so I'm asking those of you who haven't sent
> them to a keyserver to do so.

I, for one, make it a point of never using the PGP public key servers.
I make my key available by finger, and always check for people's keys
through finger.  The problem with the PGP public key servers is that
one has absolutely no control over what gets uploaded there in one's
own name.

If someone really wanted to prevent me from using PGP, for example,
that person could just upload 500 different PGP keys to the key
servers all with my E-mail address as the key ID.  Even if you already
have a PGP key of someone you trust who has certified my key, are you
really going to verify all 500 other keys until you find the one that
is certified by the real trusted person?

Moreover, what's to stop someone from downloading my key, adding an ID
"kkk grand wizard", signing it with a fake "David Duke" key, and
uploading the new signature to the PGP servers.  I don't want anyone
to be able to put such things on my PGP key in the place where most
people will go looking for it first.

Deleting a key from a PGP key server is probably even more difficult
than getting an error corrected on your credit report.  Even if one
keyserver deletes it, it will probably end up propagating there again
from another server.

The finger approach is far from perfect, because not everyone can run
a finger daemon accessible to the net at large.  Moreover, even people
with PGP keys in their .plan files often can't be fingered at their
mail hubs (in fact, people often receive E-mail at addresses which are
only DNS "MX records" which don't have corresponding IP addresses).

Thus, I'm not saying finger is the solution.  However, at least people
have control over the plausible PGP key finger locations in a way that
fits sensibly with the key ID's sought.  In other words, if I have
absolutely no affiliation with Berkeley, I should not be able to stick
a PGP key with an ID ending "<..@cs.berkeley.edu>" where people will
primarily look for such keys.  (Of course I'm welcome put the key any
other place I have access to.)

Note finally that the key distribution problem addressed by the key
servers has nothing to do with key certification.  I think one of
PGP's greatest strenghts is that anyone can certify any one else's
public key.  I hate the idea of a hierarchical system where you might
have to pay $20 and wait 3 days to get a public key (Verasign I gather
does this for SSL certificates, though the cost/wait are probably
completely different).  Thus, while I'm advocating some kind of
hierarchical key distribution mechanism, I absolutely don't want to
see that kind of structure imposed on key certification.

In fact, the key distribution problem is just the opposite of key
certification in that one wants to prevent unwanted certificates and
keys from being interpreted as condoned by the supposed owner of the
PGP key.  Even if my key really was certified by someone a year ago,
if I've now forgotten the passphrase I don't want to keep having
people grab my old key.  I also don't want random attacks on my
character appended to my PGP key where most people will seek it.

Finally, for those who desire the "light security" of encrypting with
my PGP public key even though they can't verify any of the
certificates (and I do get plenty of such PGP-encrypted mail), it
might be nice to have a system in place that at least required an
active network attack to bypass.  You might argue that this would be
worse as it would encourage more people to use untrusted PGP keys.
However, consider SSH's mechanism whereby it acquires public keys
automatically at first and then keeps verifying the keys on subsequent
sessions.  It's not perfect, but I think it definitely improves the
security of the situation.  Anyway, if the NSA started mounting
massive active attacks from the internet backbones, we would at least
find out about it soon enough.

[Posted anonymously to prevent some wise guy from getting the
brilliant idea of uploading 500 fake PGP keys in my name...]

John Anonymous MacDonald writes:
> The problem with the PGP public key servers is that
> one has absolutely no control over what gets uploaded there in one's
> own name.

Thats why people are supposed to use the web of trust to check the
keys. You claim to make your key available by finger. How do you know
that Mallet isn't switching the bits as they go down the wire to your
correspondants? The only way to verify a key is to check known good
signatures on it. Because of this, no security is needed on key
storage facilities per se -- you aren't supposed to trust keys without
signatures.

Geesh. I thought this was obvious. I guess not.

Perry

"Perry E. Metzger" <perry@piermont.com> writes:

> John Anonymous MacDonald writes:
> > The problem with the PGP public key servers is that
> > one has absolutely no control over what gets uploaded there in one's
> > own name.
> 
> Thats why people are supposed to use the web of trust to check the
> keys. You claim to make your key available by finger. How do you know
> that Mallet isn't switching the bits as they go down the wire to your
> correspondants? The only way to verify a key is to check known good
> signatures on it. Because of this, no security is needed on key
> storage facilities per se -- you aren't supposed to trust keys without
> signatures.
> 
> Geesh. I thought this was obvious. I guess not.
> 
> Perry

The web of trust just certifies that the key belongs to someone.  If
you'd read to the end of the message, you would have seen that I was
not complaining about the key certification process in PGP.  At issue is
NOT whether a key can be trusted to belong to someone, but whether or
not random people should be able to tag others' PGP keys with crap.

What I want to prevent is some person I dislike uploading his
signature on my key (particularly if he adds another ID to my key and
signs that).

How would you like it if I added a new ID to your key containing sort
of insult, certified that ID, and uploaded the new signature to the
key servers.  Alternatively, what if I uploaded 5 "vanity" keys in
your name to the PGP key servers.  Most software would download one
key, fail to certify the signature, and therefore not allow someone to
communicate with you even if that person could have verified your real
key.

I don't understand what the purpose of a centralized key server is,
when the owner of a public key should be the one to control what
certificates and tags are given out with his/her PGP key.