GPG key decryption and transaction verification

Rails
1

Do any of you have experience with this?

I am trying to figure out how to create payment processing with
e-Bullion as a backend, and am finding very little to help me in the
encryption / decryption area. The transaction is ‘verifiable’ by a
GnuPG key that they send back with the results of the transaction.
Without verifying the transaction there might be people who would try
to ‘spoof’ transactions. I have found no plugins or gem that appear to
enable me to decrypt this GPG or PGP key. I looks roughly like this
(important bits removed):

The relevant section of the POST string begins with (ATIP_VERIFICATION
is the field name / parameter name):
ATIP_VERIFICATION=-----BEGIN+PGP+MESSAGE-----%0D%0AVersion%3A+GnuPG+v1.2.6+%28GNU%2FLinux
Middle:

Ends with:
%0D%0A-----END+PGP+MESSAGE-----%0D%0A

The sample code that e-Bullion supplies comes with a script that can do
the decryption for me, but it is written in Perl. Even though I don’t
know Perl well, I can tell it is saving the key string to a keyfile on
disk, and then verifying it against my own key using a call to the gpg
binary from the command line.

So I have a few thoughts / questions.

  1. Can I call the command line directly from rails to call the actual
    GPG binary itself? I know the command line can call rails in the form
    of runners, but I need the reverse. Even with this I am not sure if it
    would help as the PGP/GPG versions are different on my host than in the
    key e-Bullion sent me.

1a) Can I call Perl from Rails with parameters to execute the script
that way?

  1. Can I use any of the many crypto plugins or gems available to Ruby?
    ruby-gpgme looked promising, but a serious lack of documentation and a
    pre-req of gpgme-config which I cannot seem to get installed on my
    machine are halting progress here. Sentry also looked ineresting, as
    did several others, but most of the crypto plugins / gems never
    directly mention PGP or GPG leaving me to wonder if they can handle it
    or not.

  2. Does anyone have some example code on how to do this? I find it
    hard to imagine that there is not a greater need for GPG key decryption
    among all the ‘business’ apps being written in Rails, yet when I search
    Google I feel as if I am alone in this.

  3. If I can figure this out I’d like to extract it and make an
    e-Bullion module for ActiveMerchant. Better yet is one already
    underway that I could assist with?

Thanks,
Peter B.