I'm sorry, I was not able to install any of the existing GPG modules properly. I am using plain  open3 instead.

Note: If you are under mod_perl and go with  open3, remember to  untie STDIN, STDOUT, STDERR or you will get strange results.

This is the code I use for open3 (with some debugging commented out):

use IPC::Open3 ();   # don't import open3

sub my_open3 {  # cmd write read error
    my %opt = (
        write => [], 
        read =>  [], 
        error => [], 
        cmd =>   "ls", 
        @_);

    my $stdin =  tied *STDIN;
    my $stdout = tied *STDOUT;
    my $stderr = tied *STDERR;

    # temporarily turn off warnings
    #     "untie attempted while 1 inner references still exist"
    { local $^W = 0;
        untie *STDIN  if $stdin;
        untie *STDOUT if $stdout;
        untie *STDERR if $stderr;
    }

    my $pid = IPC::Open3::open3(*WTRFH, *RDRFH, *ERR, $opt{cmd});
    unless ($pid) {
        print "can't fork: $!" if $DEBUG;
        return 0;
    }
    # local $SIG{PIPE} = sub { 1 };    # $pipe_error = 1 };
    print WTRFH @{$opt{write}};
        # || return 0; # die "can't write: $!";
    close (WTRFH);    # || return 0;       #die "bad pipe: $! $?";
    @{$opt{read}} =  <RDRFH>;
    @{$opt{error}} = <ERR>;
    close (RDRFH);    # || return 0;       #die "bad pipe: $! $?";
    close (WTRFH);    # || return 0;       #die "bad pipe: $! $?";
    waitpid $pid, 0;

    tie *STDIN,  ref $stdin, $stdin   if $stdin;
    tie *STDOUT, ref $stdout, $stdout if $stdout;
    tie *STDERR, ref $stderr, $stderr if $stderr;

    return 1;  # ok
}
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This is an example on how to use it:

    my $gpg = "gpg ...options...";
    my ($id, $pass, @data) = ('fglock','xxx',"data\n","data\n");
    my (@result, @err);
    unshift @data, $pass . "\n";
    $cmd = "$gpg --no-tty --local-user $id --passphrase-fd 0 --decrypt
+";
    my_open3(
        cmd =>      $cmd,
        write =>    \@data,
        read =>     \@result,
        error =>    \@err );
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