Generate signed cookies for Cloud CDN using Perl

[marcosocamargo]

Is there a way of adding the routine for generating signed cookies for Cloud CDN using Perl? This is what I have so far but Cloud CDN doesn't seem to accept the results of this routine as a signed cookie. I would like to have somebody review it and find out what is incorrect. It was derived from the PHP code. I am willing to test it in my website.
Thanks!

use MIME::Base64 qw(encode_base64 decode_base64);

# Just one of these are necessary but I wasn't sure which one to use
use Digest::SHA 'hmac_sha1_base64';
use Digest::SHA 'hmac_sha1_hex';

use Time::Local qw(timelocal);

# Not necessary if the URL doesn't need to be escaped
use URI::Escape;

use MIME::Base64::URLSafe;

sub sign_cookie {
   # Escape diacritics contained in the URL. This is not necessary for a general subroutine since the URL would
   # be already escaped.
    my ($url_prefix, $key_name, $base64_key, $expiration_time) = @_;
    my @url_prefixes = split "\/", $url_prefix;
    my $escaped = "/";
    for my $i (1 .. $#url_prefixes) {
      my $escape = uri_escape_utf8($url_prefixes[$i]);
      $escaped .= "$escape" . "/";
   };
   my $escaped_url_prefix = "https://storage.googleapis.com/recpres$escaped";

   # Encode URL prefix
   my $encoded_url_prefix = $escaped_url_prefix;
   $encoded_url_prefix = Encode::encode('utf8', $escaped_url_prefix, '');
   $encoded_url_prefix = urlsafe_b64encode($encoded_url_prefix);
   # Base64 must be padded with =
   while (length( $encoded_url_prefix) % 4) {
     $encoded_url_prefix .= '=';
   }
   $encoded_url_prefix = Encode::decode('utf8', $encoded_url_prefix);

   # Time stamp since 00:00:00 UTC, January 1, 1970
   my $time = time();
   my $expiration_timestamp = time() + $expiration_time;
  
   my $gm_time = gmtime($expiration_timestamp);
   my @dates = split / /, $gm_time;
   # Generate a date that is human readable in GMT time but it is not necessary 
   my $expiration_date = "$dates[0], $dates[2] $dates[1] $dates[4] $dates[3] GMT";

   # Decode key
   my $decoded_key = urlsafe_b64decode($base64_key);

   # Create the policy
   my $policy = "URLPrefix=$encoded_url_prefix:Expires=$expiration_timestamp:KeyName=$key_name";

   # Sign the policy
   # HMAC SHA1 signing
   my $signature = hmac_sha1_base64($policy, $decoded_key);
   # Base64 must be padded with =
   while (length( $signature) % 4) {
     $signature .= '=';
   }

   # Concatenate all fields to create cookie
   my $signed_cookie = qq(URLPrefix=$encoded_url_prefix:Expires=$expiration_timestamp:KeyName=$key_name:Signature=$signature);
   return $signed_cookie;
}