hi there!

maybe you are interested in the simple dired/gpg 
interface provided in the attachment. 

> ...
> ;; 2005-02-14T09:22:05+0100 Mirko.Luedde@SAP.com: provide primitive
> ;; interface to GNU privacy guard `gpg'. this avoids some shortcomings
> ;; of the `mailcrypt' package.
> ;; 
> ;; - mailcrypt does not work for gnu-emacs/w32. 
> ;;
> ;; - mailcrypt operates on buffers rather than files. this poses
> ;;   problems for binary files and with emacs auto-saved files.
> ...

the main entry is `dired-do-gpg'. 

for the diffs, use diff or search for `gpg' or `Mirko'. 

best regards, mirko.