OpenPGP smartcard - authentication key

[Werner Koch]

On Mon, 02 May 2005 11:37:17 +0200, Wolfgang Rosenauer said:

> As far as I understood it should be possible to save a SSH RSA key to
> the OpenPGP smartcard as authentication key.
> If this is true, how can this be done?

If that is an 1024 bit RSA key, this is indeed possible.  The HOWTO
will tell you:

  http://www.gnupg.org/documentation/howtos.html#GnuPG-cardHOWTO

In short: Use gpg --edit-key and then the command keytocard.  The
problem might be to convert an SSH key to a GnuPG key. There is no
instant solution for 1.4 - with 1.9 and the gpg-agent SSH support is
included and a mere ssh-add will be suffcient; but well the key is
then stored in gpg-agent's own format.

In general I do not suggest to do this at all.  Better generate a new
key on-card and use this as your new ssh key. It is pretty simple to
change your ssh key and this allows you to slowly retire your old ssh
key.


Shalom-Salam,

   Werner