back signatures

[David Shaw]

On Fri, Nov 04, 2005 at 02:24:09PM -0500, David Shaw wrote:
> On Fri, Nov 04, 2005 at 10:15:16PM +0300, Pawel Shajdo wrote:
> > Salve!
> > Can somebody explain me what is "back signatures"?
> > Manual not very clear about this.
> 
> It's a countermeasure against an attack against signing subkeys.
> Basically, the primary key signs all subkeys.  With backsigs, the
> signing subkey also signs the primary key.
> 
> Without this, an attacker can "steal" a signing subkey from someone
> else and try and pretend that a signature came from his own key.  It's
> not a particularly good attack: the attacker can't issue signatures to
> prove his ownership.

I should add that this is a new feature for 1.4.3.

David