long-term GPG signing key

Guus Sliepen guus at sliepen.eu.org
Thu Jan 12 12:26:16 EST 2006

On Tue, Jan 10, 2006 at 03:28:49AM -0600, Travis H. wrote:

> I'd like to make a long-term key for signing communication keys using
> GPG and I'm wondering what the current recommendation is for such.  I
> remember a problem with Elgamal signing keys and I'm under the
> impression that the 1024 bit strength provided by p in the DSA is not
> sufficiently strong when compared to my encryption keys, which are
> typically at least 4096-bit D/H, which I typically use for a year.
> The whole reason I'm using a signing key is that I have numerous older
> keys which have now expired and so the signatures on them are
> worthless.  I don't attend many keysigning parties so it's hard to
> make the system work without collecting signatures over a long period
> on some very high strength key.  Also, I'd like to use the signing key
> as a kind of identity, not tied to any particular email address, and
> only used to sign communication keys, which *are* tied to a email
> address and have shorter expiration times.
> Does anyone have any suggestions on how to do this, or suggestions to
> the effect that I should be doing something else?

By default, GPG creates a signing key and an encryption key. The signing
key is used both for signing other keys (including self-signing your own
keys), and for signing documents (like emails). However, it is possible
to "split" the signing key into a master key that you only use to sign
other keys, and a key dedicated to signing documents. You can revoke the
latter key and create a new one whenever you want, the master key is
still valid. Also, when people sign your key, they sign your master key,
not the subkeys. The signatures you accumulated will also still be
valid. You can also keep the master key safely tucked away on an old
laptop that you keep in a safe, and only export the subkeys to your
workstation. That way the master key is very safe.

About keys being tied to "email addresses" (uids): you can create a uid
with just your name, no email address, and if you like a comment with
your birthday or passport number in it. Let people sign that uid.

Met vriendelijke groet / with kind regards,
    Guus Sliepen <guus at sliepen.eu.org>
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