Example for Cookie-based Access Token with NginX HttpSecureLinkModule http://wiki.nginx.org/HttpSecureLinkModule and PHP (in this case for Typo3). Note that Typo3 needs to set the cookie as shown in token.php

nginx.conf

# Excerpt of nginx config file
#..
#
                set $ts 0;
                if ($cookie_TOKEN ~ ",(.*)$") {
                        set $ts $1;
                }
                secure_link $cookie_TOKEN;              # See TYPO3_ACCESSTOKEN
                set $sec CHANGE_THIS_SHARED_SECRET;     # See TYPO3_ACCESSKEY
                secure_link_md5 $sec$ts$sec;

                if ($secure_link != "1") {
                        return 403;
                }
#
#..
#
                fastcgi_param   TYPO3_ACCESSTOKEN       TOKEN;
                fastcgi_param   TYPO3_ACCESSKEY         CHANGE_THIS_SHARED_SECRET;
                fastcgi_param   TYPO3_ACCESSTIME        3600;
#
#..

token.php

#!/usr/bin/php
<?
$sec    = $argv[1];     // $TYPO3_ACCESSKEY
$delta  = $argv[2];     // $TYPO3_ACCESSTIME

$ts     = time()+$delta;
$str    = "$sec$ts$sec";

$hash   = str_replace('=','',strtr(base64_encode(md5($str,true)),'+/','-_'));

$cookie = "$hash,$ts";  // header("Set-Cookie: $TYPO3_ACCESSTOKEN=$cookie");

printf("SEC=%s TS=%s COOKIE=%s\n", $sec, $delta, $cookie);
?>