#!/usr/bin/perl -w
use strict;


my %hash1 = ();
$hash1{key1}{key2}{key3}{A} = "hello";
$hash1{key1}{key2}{key3}{B} = "bye";

my $key = "{key1}{key2}{key3}";

my $new_hash = {};
$new_hash = \%hash1;

foreach (keys %{$$new_hash{$key}}) {

    print "$_ \n";

}