[gentoo-dev] Re: [gentoo-core] on the matter of security and cryptography

[Maik Schreiber]

> cracker gets my box, keylogs and gets my key's password (or bruteforces
> it).

There. You just said it. "Gets my box, gets my key's password". Remember
the first rule of key management? Protect your private key!

If your private key was protected like nothing else, he couldn't get it in
the first place.

> then he uses my key to sign his own replacement key, adds that to
> the keyring and has his part set.

Assumed he can get his key into the keyring, this wouldn't gain him
anything. He still would need to have his key checked for.

As I personally ignore any signatures on any key that are from people I
don't personally know and trust, "your" signature on his key wouldn't
compromise anything in my system, since his key is effectively untrusted.

> all this should be quite simple to do without actually harming enough or
> hampering enough to be detected in a system.

I really doubt anyone but me is able to steal my GPG private key. In fact,
I have two PGP keys for several years now, with corresponding revocation
copies, and there hasn't been a single case where someone got access to my
private keys.

> after this, he only needs to slowly hack into one or five -system
> builds, and either use my key, or the new fake one, to go ahead and
> smash things. wham, haxor karma.

Like I've said, his own key (even if signed by "you") wouldn't get him
anything. So an attacker would be more after your key than create his own
and let "you" sign it.

> that was the sort of faked signatures I was counting for.

If it's a faked signature that has been made with your key (without you
knowing), that's your problem. Protect your private key, and all is fine.

> to have the revocation signatures spread out among the (senior?)
> developers and allowing them to revoke others keys would be necessary
> for security

No. Nobody gets a revoked key copy from me if I don't personally know and
trust them in the first place. For example, the only person that has
revocation access for my PGP keys is a friend of mine which I personally
trust for several years now.

> but that still would not help with his newly generated key
> thats released in mine (or drobbins?) name.

You didn't get it. There's no such way as to "release" or "create" a key
"in someone's name". You create a key, and it's created by you. You
release a key, and it's released by you (actually it doesn't matter who
releases it). Someone signs a key, and it's signed by them. It's that
simple.

As for trusting signatures on particular keys, see above.

> Now that I think of it in theese terms, public keys should not be
> distributed with the rsync servers, but only with the iso's and
> downloaded from keyservers.

What's the whole point of that? Why do you trust key servers more than
your local rsync mirror?

You might say you don't know the persons running rsync mirrors. Then tell
me, who's running the key servers? I don't know either, and I don't care.
It simply doesn't matter. The only thing that matters is _widespread_
distribution of the public key.

-- 
Maik Schreiber, Gentoo Developer
http://www.gentoo.org
mailto:blizzy@g.o