#!/usr/local/bin/perl -w

# gpgtest.cgi -- Encrypt to a Public Key from CGI
# Runs on perl 5.005_03 / FreeBSD 4.3

$|=1;
print "Content-type: text/html\n\nSTARTED<BR>";

use lib qw(/home/www/myusername/data/sitelib);
use CGI::Carp qw(fatalsToBrowser warningsToBrowser);
use IO::Handle;
use GnuPG::Interface;

# Note you should have imported a public key into gpg already.
# It must be trusted, which can be done without any secret keys
# being installed by editting .gnupg/options (read the comments).
# The encrypted text is ascii armored and can be copied or 
# downloaded for decryption with a GPG client like WinPT / GPG
# See www.gnupg.org for documentation and links to client software.
# Perl libs including Class::MethodMaker built with local prefix
# using perl Makefile.PL LIB=~/data/sitelib

my @plaintext = ("just another perl hacker");    # plaintext lines
$m = 'secretkeyowner@secretdomain.com';          # email address
my $gpghomedir = '/home/www/myusername/.gnupg';  # path to .gnupg
my $gnupg = GnuPG::Interface->new();             # instantiate
$gnupg->options->hash_init( armor   => 1,
							homedir => $gpghomedir,
							verbose => 1,
							meta_interactive => 0
							);                   # init
$gnupg->options->push_recipients($m);            # email addresses

# Set up some handles to communicate with gpg
my ( $input, $output, $error ) 
 = ( IO::Handle->new(), IO::Handle->new() , IO::Handle->new() );
my $handles = GnuPG::Handles->new( 
     stdin => $input, stdout => $output, stderr => $error );

my $pid = $gnupg->encrypt( handles => $handles );# open write connxn
foreach (@plaintext) { print $input $_; }        # send msg to gpg
close $input;                                    # close write.

my @ciphertext =();                              # now read encrypted
while (<$output>) { push(@ciphertext,$_); }      # msg from gpg.
waitpid $pid, 0;                                 # clean up the done
                                                 # GnuPG process.

open (OUT,">testoutput");                        # Save to disk.
foreach (@ciphertext) { print OUT $_ ; };
close(OUT);

print "<PRE>OK:\n" . join("",@ciphertext);       # View in browser.
print "\nWARNINGS:<BR>\n";                       # View gpg stderr
print $_ while (<$error>);                       # reading in buffer.
close $error;                                    # close buf handle.

exit 0;

Output:

STARTED

-----BEGIN PGP MESSAGE-----
Version: GnuPG v1.0.6 (FreeBSD)
Comment: For info see http://www.gnupg.org
hQGOA6gWzASXj2Y7EAX+OYWAWeuP52WbB1/zc90H9VBgHBI/DUTROLzjxguyiFa8
HfRx1zgbeeALaJqmaSnM2uALdjFyIK0wfMwj7HtdUyOGFKZmW4g8fSolbLSMq++H
SWoggl+grK2OfsL06ScKKu7ycq6TKRKg+/tkHSkf5pHDg1wBY+yPCSssTINtnL+W
0c1vb9+WOXUSbS6x7O7sZjY+b+YzTAL78gWqcYExm+yLXaURHGF2MbhKAS8+L9VH
MfsdSinLGW3m1ddgP1bGBf0WLWYTrhTjb2eASHOLoAYCkedI6meCQklOOjcnGd6P
jYSgJusmdiztuXOFOetL8q53H2X9Vvc9zOuqGdgmSV6VqLFvocb6gMzXzR/kdowZ
hzq7iAWHWs6yNXn7NprCgujetHMLpMwpFeKAN45rkEvQjSyiObuwxhYRkNQclYoT
I39QlRG7TRiXbeaKrrpY+RhsP96vPOT9wBb93fXkKlOVVXGm7farR2ces+/6RZFG
c3RRcAWXJwUpLxi6TurdRgrSSAGa1oCjFkzEW4zudhKvAp5TzS7x/fXK+Nd5TTSJ
uMiYWzOxpuBUY2gACoJwoHdlfjE/TFd4kyJ+FA+u+3ZHlJ7a0SESCNo82Q==
=A/7j
-----END PGP MESSAGE-----

WARNINGS:
gpg: Warning: using insecure memory!
gpg: using secondary key XXXXXXXX instead of primary key XXXXXXXX
gpg: This key belongs to us
gpg: reading from `[stdin]'
gpg: writing to stdout
gpg: ELG-E/RIJNDAEL encrypted for: XXXXXXXX XXXX (XXXXXXXXX)