Hello Michaels,

The option key_path is from module Net::SFTP::Foreign not from Net::SFTP.

Can you try this:

#!usr/bin/perl
use strict;
use warnings;
use Net::SFTP::Foreign;

my %args = ( host     => "127.0.0.1",
         user     => "user",
         port     => "10022",
         key_path => "path/sftp_download" );

my $sftp = Net::SFTP::Foreign->new(%args);
$sftp->die_on_error("Unable to establish SFTP connection");

my $ls = $sftp->ls('/sample/path')
    or die "unable to retrieve directory: ".$sftp->error;

print "$_->{filename}\n" for (@$ls);
[download]

I would use full path to the SSH keys of your PC. For example /home/user/.ssh/id_rsa. It seems that from the directory that you are executing the script the keys are not reachable.

Update: You are using path/sftp_download as the location of you SSH keys. This is the location that you want to store the file I assume. First step is to correctly assign the SSH keys file. Use key_path => "/home/user/.ssh/id_rsa" on the code above and let us know if this works.

Hope this helps, BR