Re: PGP and pseudonyms

At 03:08 PM 4/28/96 -0700, Steve Reid wrote:
>Suppose someone were using a pseudonym, and had a seperate PGP key for
>this pseudonym. If this person's secret keyring were stolen, could
>person=pseudonym be revealed, based on the key ID? Or would it require
>knowing the passphrase? 

Yes, the person=personna would be revealed.  No, a passphrase would not be
needed.

To demonstrate try "pgp -kv secring.pgp" and see what you get.

I hope this gets fixed in PGP 3.0.
---
Alan Olsen -- alano@teleport.com -- Contract Web Design & Instruction
        `finger -l alano@teleport.com` for PGP 2.6.2 key 
                http://www.teleport.com/~alano/ 
  "We had to destroy the Internet in order to save it." - Sen. Exon

> >this pseudonym. If this person's secret keyring were stolen, could
> >person=pseudonym be revealed, based on the key ID? Or would it require
> >knowing the passphrase? 
> 
> Yes, the person=personna would be revealed.  No, a passphrase would not be
> needed.
> To demonstrate try "pgp -kv secring.pgp" and see what you get.

I kinda figured that... I was just wondering if maybe the info could be
altered, so that the real info can't be figured without getting the
passphrase. 

> I hope this gets fixed in PGP 3.0.

I guess pseudonymity(sp?) wasn't the main concern when PGP was created.

I suppose a temporary fix would be to not use an ordinary PGP passphrase,
but rather encrypt the whole secring.pgp file. Decrypt it when you need
it, and be very careful to properly clean up when you're done. 


=====================================================================
| Steve Reid - SysAdmin & Pres, EDM Web (http://www.edmweb.com/)    |
| Email: steve@edmweb.com   Home Page: http://www.edmweb.com/steve/ |
| PGP Fingerprint: 11 C8 9D 1C D6 72 87 E6  8C 09 EC 52 44 3F 88 30 |
|              -- Disclaimer: JMHO, YMMV, IANAL. --                 |
===================================================================:)

On Sun, 28 Apr 1996, Steve Reid wrote:

> > >this pseudonym. If this person's secret keyring were stolen, could
> > >person=pseudonym be revealed, based on the key ID? Or would it require
> > >knowing the passphrase?
[...]
> I guess pseudonymity(sp?) wasn't the main concern when PGP was created.
> 
> I suppose a temporary fix would be to not use an ordinary PGP passphrase,
> but rather encrypt the whole secring.pgp file. Decrypt it when you need
> it, and be very careful to properly clean up when you're done.

Huh?

Just use multiple secring.pgp files, and toggle PGPPATH. What's the
problem? 

I guess that wouldn't be so convenient on the Mac version, I guess, but
you could write an AppleScript to swap file/folder names.

-rich

> > I suppose a temporary fix would be to not use an ordinary PGP passphrase,
> > but rather encrypt the whole secring.pgp file. Decrypt it when you need
> > it, and be very careful to properly clean up when you're done.
> Huh?
> Just use multiple secring.pgp files, and toggle PGPPATH. What's the
> problem? 

You don't understand the problem we're concerned about... The problem is,
the "real" person is in posession of the pseudonym's secret PGP key, and 
PGP doesn't try to hide that fact.

Suppose John Doe is using the pseudonym "Evil Bastard". Naturally, he has
a PGP key for his Evil Bastard identity. Now suppose someone gets into his
computer. This person would be able to find Evil Bastard's secret key. 
Fortunately, the snoop would not be able to use the key, since it would be
encrypted with a secure PGP passphrase. However, they would still be able
to use the command "pgp -kvv secring.pgp", and that shows the key ID of
each secret key. 

The key ID is the lower 64 bits of the public key, but it's included in
unencrypted form on the secret keyring as well, to identify the secret
key. The person who snooped the secret keyring would be able to see that
John Doe has the secret key with the ID of (for example) 13579BDF. Since
the ID of Evil Bastard's well-known public key is also 13579BDF, the snoop
now knows that John Doe is in posession of a secret key that corresponds
to Evil Bastard's public key, which proves that John Doe *IS* Evil Bastard. 


=====================================================================
| Steve Reid - SysAdmin & Pres, EDM Web (http://www.edmweb.com/)    |
| Email: steve@edmweb.com   Home Page: http://www.edmweb.com/steve/ |
| PGP Fingerprint: 11 C8 9D 1C D6 72 87 E6  8C 09 EC 52 44 3F 88 30 |
|              -- Disclaimer: JMHO, YMMV, IANAL. --                 |
===================================================================:)

The solution is to store your keys on an encrypted filesystem,
such as Cryptdisk or CFS.  Thus, possession of the keyrings does no
good, because they're encrypted.  I've found that leaving PGP on the
encrypted partition makes me less likely to get error messages like
'keyring unavailable,' and I do get the obvious: pgp: Command not
found


Adam

Steve Reid wrote:

| > > I suppose a temporary fix would be to not use an ordinary PGP passphrase,
| > > but rather encrypt the whole secring.pgp file. Decrypt it when you need
| > > it, and be very careful to properly clean up when you're done.
| > Huh?
| > Just use multiple secring.pgp files, and toggle PGPPATH. What's the
| > problem? 
| 
| You don't understand the problem we're concerned about... The problem is,
| the "real" person is in posession of the pseudonym's secret PGP key, and 
| PGP doesn't try to hide that fact.
| 
| Suppose John Doe is using the pseudonym "Evil Bastard". Naturally, he has
| a PGP key for his Evil Bastard identity. Now suppose someone gets into his
| computer. This person would be able to find Evil Bastard's secret key. 
| Fortunately, the snoop would not be able to use the key, since it would be
| encrypted with a secure PGP passphrase. However, they would still be able
| to use the command "pgp -kvv secring.pgp", and that shows the key ID of
| each secret key. 

-- 
"It is seldom that liberty of any kind is lost all at once."
					               -Hume