Why not create a module which simply invokes GnuPG's gpg command for your needs? If and when there is a Perl module with more complete support, you can revise your module to use it.

beecause eeet eexists :) GnuPG - Perl module interface to the GNU Privacy Guard (v1.x.x series)
GnuPG::Interface - Perl interface to GnuPG