How do i auto sign rpm's with rpmbuild?

[Mark]

> I don't personally see the problem with manually signing though.  I
> build packages in mock under a build account setup specifically for
> packaging.  Once the packages are built, I sign them from my normal
> user account (e.g.: rpm --addsign ~build/mock/<package>/*.rpm).

well.. signing a few packages by hand isn't a problem at all.
but signing about 50 packages is.

And removing the password completely seems like a good possibility.
i wish rpmbuild (or rpm) was allowing something like this:
rpmbuild -ba --sign="the key" my_rpm.spec
or
rpmbuild -ba --sign --passphrase "the key" my_rpm.spec

Just the option for that would be gread.