#!/usr/bin/php
<?php
	/**
	 * Usage: $0 <master-key> <proxy-base-url>
	 */

	$_ARGV = $_SERVER['argv'];
	$CIPHER = 'aes-128-cfb';

	function base64url_encode($data) { 
		return rtrim(strtr(base64_encode($data), '+/', '-_'), '='); 
	} 

	function usage() {
		global $_ARGV;
		print "Usage: {$_ARGV[0]} <master-key> <proxy-service-domain>\n";
		exit(1);
	}

	if (count($_ARGV) != 3 || !preg_match('@https?://.*@i', $_ARGV[2])) {
		usage();
	}

	$MASTER_KEY = $_ARGV[1];
	$DOMAIN     = $_ARGV[2];
	$DOMAIN_KEY = hash_hmac('SHA512', "proxy:$DOMAIN", $MASTER_KEY, TRUE); 

	print base64url_encode($DOMAIN_KEY) . "\n";

?>
