Talking about Cryptodevices... which one?

MFPA 2014-667rhzu3dc-lists-groups at riseup.net
Sat Feb 7 19:20:06 CET 2015


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Hi


On Friday 6 February 2015 at 11:59:41 PM, in
<mid:1840536.GW9g4AXMVe at mani>, Johannes Zarl wrote:



> You're conflating two different threats here.

I was referring to the threat "the host computer might be infected
with malware".



>  A
> smartcard *does* protect you from anyone trying to
> steal your private keys.

If they have control of your computer, do they really need to steal
the private keys? Maybe they can achieve their aims remotely, using
the keys in situ on the smartcard. And, of course, a smartcard is a
physical item that can be stolen.



> It does not prevent an attacker from stealing the pin.

I guess a smartcard reader that can only accept the key via its own
keypad would help here. If we can be sure it cannot be modified to
cache the PIN or accept it via the host computer.



> It does not prevent an attacker from deleting your key.

Always best practice to keep a backup. Even without foul-play it would
be needed if the smartcard was lost or broken.



> It does not prevent an attacker from tricking you into
> signing or decrypting a message.

Or making your system sign/decrypt more than one message at a time,
when you were aware of just the one?



> Under some
> circumstances it does not even protect against key-
> revocation.

As has already been mentioned, an "offline" main key stops this.



> Having said all that, I still think it is a worthwhile
> goal to protect the key-material itself using
> smartcard-like hardware / an HSM.

Protecting the private key material is the goal. Use of smartcard and
reader is an example of a strategy to follow in pursuit of that goal.
Use of an offline main key is another example.



> The protection
> against key-theft does radically decrease your attack
> surface in many cases.

As always, it depends on your threat model.


- --
Best regards

MFPA                    mailto:2014-667rhzu3dc-lists-groups at riseup.net

A candle loses nothing by lighting another candle
-----BEGIN PGP SIGNATURE-----
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=
=dpIz
-----END PGP SIGNATURE-----




More information about the Gnupg-users mailing list