checking md5sum of installed packages

[Jim Breton <jamesb-debian@alongtheway.com>]

I'm sure this has come up before but searching the archives for "dpkg
md5sum" etc. just comes up with WAY too many matches.  :(

Anyway my question is: is there a dpkg command I can run that will check
the md5sums of all my dpkg-installed files?

I know on RedHat you can do: rpm -Va

I see that I can do: dpkg -l
	to get a list of my installed packages.  Would I have to use
that output in a shell script (perhaps with xargs) etc. to do this?  Or
is there a straight-forward way?  I don't see any reference to this in
the man page.

Thanks.