iButton Crypto (Slightly off topic)

[Werner Koch]

On Mon, 6 Mar 2000, Michael Sobolev wrote:

> Does it mean that you think it's not a very good idea to use iButtons to store
> the secret keys?  What's the point of storing *a part* of the passphrase?

There is not much need to do so.  With a good passphrase your secret
key is protected very well - a random string stored in a iButton gives
a very good passphrase.  What happens if you lose your iButton with
the secret key? - It is not so difficult to get it out of that device.

If you just lose your iButton with the passphrase, an attacker must
find that button and get access to your secret key (and the additional
passphrase).

The secret key has to be transferred to your desktop box anyway
because the iButton is not fast enough to do the crypto operations.
And a memory only iButton is much cheaper. 
  
   Werner