Security updates are untrusted

[Carl Johnson <carlj@peak.org>]

I was just noticing that aptitude warns that a number of packages are
listed as untrusted.  I checked using 'apt-cache policy' and those
appear to be security updates and are from security.debian.org.  I
already have the debian-archive-keyring, so I would have expected that
would cover security updates, but obviously not.  I also tried manually
picking up and installing the key recommended at security.debian.org,
but that didn't change anything.

Can anybody suggest what I need to do to get the security updates
properly recognized?

Thanks for any suggestions.
-- 
Carl Johnson		carlj@peak.org