Problems using 10kbit keys in GnuPG instead of 4kbit keys

Pete Stephenson pete at
Tue Sep 10 15:42:53 CEST 2013

On Tue, Sep 10, 2013 at 3:31 PM, Ole Tange <tange at> wrote:
> I have not heard of the primary certification key before. Is it the
> 'C' in 'usage: SCEA'?

Yes. The certification key is used when signing (more properly,
"certifying") other people's public keys.

A signing key can be used for signing files or messages but the
certification key is used for signing other people's keys.

In short, it's the "primary" key.

> Can that be changed without losing signatures on the public key? If
> so, then the size of that can be increased slowly when needed.

Unfortunately not. It is the primary key and its properties (e.g. key
length) cannot be changed.


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